A method and apparatus for processing a signal. The signal is received in a receiver system in a satellite. The signal has a range of frequencies in which information is carried in a number of channels having a number of frequencies within the range of frequencies. The number of frequencies for a channel in the number of channels changes within the range of frequencies over time. The signal is transmitted using a transmitter system in the satellite. The signal is unprocessed to identify the number of frequencies for the channel used to carry the information by the satellite.

BACKGROUND INFORMATION

The present disclosure relates generally to communications and, in particular, to satellite communications. Still more particularly, the present disclosure relates to a method and apparatus for reducing interference with satellite communications.

Many different types of satellites are present for different purposes. For example, satellites include observation satellites, communication satellites, navigation satellites, weather satellites, research satellites, and other suitable types of satellites. Additionally, space stations and human spacecraft in orbit are also satellites that may perform different purposes.

With respect to satellites, communication of information is performed by most satellites. Communications may include receiving information and transmitting information. The information received may be commands, data, programs, and other types of information. Information transmitted by satellites may include data, images, communications, and other types of information.

When a satellite is primarily used to relay communications, the satellite may relay information to different destinations across the Earth using signals. In these illustrative examples, the signals are used to establish a communications link between the satellite and another device. Typically, when communications are sent to a satellite, the communications link is in an uplink. Information transmitted by a satellite is typically in a downlink.

For example, a transmitter in one location may send information in a communications link in the form of an uplink to a satellite. The satellite may process the information and send the information in a communications link in the form of a downlink to a destination terminal in another location across the globe.

In other examples, satellites may relay the information received to multiple destination locations. For example, the information may be a video broadcast received by the satellite in signals for an uplink to the satellite by a transmitter for a user. The satellite may then retransmit this video broadcast in signals in downlinks to the multiple destination locations.

In still other examples, if the destination device is not in the coverage area of a satellite, that satellite may relay the communications to a second satellite via a communications link in the form of a satellite crosslink. The second satellite may then send the communication in a downlink to the destination location.

Users transmitting these types of communications may desire that the communications be protected from interference by others. This interference may be anything which alters, modifies, or disrupts a signal from the transmitter as the signal travels along a channel between the transmitter and the receiver. This interference may be unintentional interference from the environment or intentional interference from others. This intentional interference may be known as “signal jamming.”

Signal jamming is a process of intentionally transmitting radio signals using the same or substantially the same frequencies as those in the uplink, downlink, or both the uplink and downlink to disrupt communication of information by a sender. For example, an adversary may attempt to jam communications signals from an operator at a military ground station to prevent the operator from communicating with troops in other locations. In some cases, users perform signal processing, such as frequency hopping, to protect satellite communications from signal jamming. Users may also perform signal processing. This signal processing may include, for example, without limitation, frequency hopping to protect satellite communications from unintentional sources of interference, and to prevent signal detection, signal interception, or other undesired results.

When relaying communications via satellite, some current and proposed anti-jam systems perform a large part of this signal processing onboard the satellite in orbit. This signal processing may be, for example, frequency hopping, frequency dehopping, time permutation, and time de-permutation. The signal processing also may include, for example, channel interleaving, scrambling, rotation, interspersal techniques, or other types of processing that may be used to increase the security of the communications.

In particular, frequency hopping and frequency dehopping may be used to reduce or avoid interference with communications. In other words, the frequency on which information is carried may be changed over time.

Frequency hopping involves employing a carrier frequency that changes over time. Frequency dehopping involves reversing the process of frequency hopping to identify a carrier frequency that does not change over time in order to enable extraction of the information from the carrier wave.

Signal processing can be a calculation intensive and complex process. As a result, additional equipment may be needed onboard the satellite to perform this signal processing. Consequently, currently used signal processing systems intended for use onboard satellites may increase the size, weight, and cost of the satellite.

Additionally, upgrading or changing signal processing systems may be more difficult than desired. For example, if more sophisticated equipment is needed to perform onboard signal processing on a satellite, a satellite may be modified or replaced. The process of modifying or replacing a satellite may be more time intensive and costly than desired.

In other cases, the increased size, weight, and complexity of a modified satellite may result in undesired or inefficient performance of the satellite. Therefore, it would be desirable to have a method and apparatus that takes into account at least some of the issues discussed above, as well as other possible issues.

SUMMARY

In one illustrative embodiment, an apparatus comprises a receiver system in a satellite and a transmitter system in the satellite. The receiver system is configured to receive a signal having a range of frequencies in which information is carried in a number of channels having a number of frequencies within the range of frequencies. The number of frequencies for a channel in the number of channels changes within the range of frequencies over time. The transmitter system is configured to transmit the signal. The signal is unprocessed to identify the number of frequencies for the channel in the number of channels used to carry the information by the satellite.

In another illustrative embodiment, a method for processing a signal is present. The signal is received in a receiver system in a satellite. The signal has a range of frequencies in which information is carried in a number of channels having a number of frequencies within the range of frequencies. The number of frequencies for a channel in the number of channels changes within the range of frequencies over time. The signal is transmitted using a transmitter system in the satellite. The signal is unprocessed to identify the number of frequencies for the channel used to carry the information by the satellite.

DETAILED DESCRIPTION

The illustrative embodiments recognize and take into account one or more different considerations. For example, the illustrative embodiments recognize and take into account that frequency dehopping and frequency hopping of a signal may be performed at a terrestrial gateway, rather than onboard the satellite. In these illustrative examples, frequency dehopping may be referred to as dehopping and frequency hopping may be referred to as hopping.

One or more illustrative embodiments provide a method and apparatus for processing a signal. A signal is received in a receiver system in a satellite. The signal has a range of frequencies in which information is carried in a number of channels having a number of frequencies within the range of frequencies. This range of frequencies may be a wideband frequency hopping signal. The channel that is identified may be the frequency or frequencies in which the information is carried. The signal is transmitted to a remote gateway location using a transmitter system in the satellite. The signal is unprocessed by the satellite to identify the channel used to carry the information.

In other words, none of the components in the satellite identify the information carried in the signal. In these illustrative examples, the satellite acts much like a transponder in which dehopping and hopping is not performed with respect to the signal. The signal is relayed by the satellite to another gateway destination where dehopping and hopping is performed.

In other words, the satellite communication system may use satellite-based transponders to relay communications to non-orbital gateway devices. As a result, the cost, complexity, and size of satellites used to relay communications between orbital and non-orbital devices may be reduced.

With reference now to the figures and, in particular, with reference toFIG. 1, an illustration of a block diagram of a communications environment is depicted in accordance with an illustrative embodiment. In this illustrative example, communications environment100includes communications network102.

As depicted, communications network102has orbital portion104, user terminal portion105, and terrestrial portion106. Orbital portion104may be any portion of communications network102that is located in components that may orbit Earth108. For example, orbital portion104includes satellites110in orbit around Earth108.

In these illustrative examples, satellites110are artificial objects placed into orbit around Earth108. In some illustrative examples, satellites110also may include spacecraft and space stations when these spacecraft or space stations are in orbit around Earth108.

As depicted, user terminal portion105includes platforms122which include terminal devices119. Terminal devices119have direct links to satellites110in order to transmit information114, receive information114, or both transmit and receive information114that is to be conveyed between platforms122and other users in communications network102. For example, terminal devices119in platforms122may use satellites110to send information114to other terminal devices119or terrestrial users113. Platforms122with terminal devices119may be located in space, on land, in the air, on the water, under the water, or some combination thereof.

In this illustrative example, a platform in platforms122may be, for example, a mobile platform, a stationary platform, a land-based structure, and an aquatic-based structure. More specifically, the platform may be a surface ship, a tank, a personnel carrier, a train, a submarine, an automobile, a power plant, a bridge, a dam, a house, a manufacturing facility, a building, and other suitable platforms.

Terminal devices119in platforms122in user terminal portion105may be devices configured to send information114to satellites110using communications links117in these illustrative examples. Information114may then be sent via satellites110to other users in communications network102.

In this illustrative example, terrestrial users113may be comprised of users connected to network112. In these examples, terrestrial users113may be applications, computers, people, or other suitable types of users. Information114may be conveyed to terrestrial users113using satellites110and/or gateways120in ground system118.

Terrestrial portion106of communications network102may include any devices that are located on or within the atmosphere of Earth108. Terrestrial portion106may include, for example, network112. Network112may be located on land, in the air, on the water, under the water, or some combination thereof.

Network112may take various forms. For example, network112may be at least one of a local area network, an intranet, the Internet, a wide area network, a circuit-switched network such as synchronous optical network (SONET), some other suitable network, or some other combination of networks. As used herein, the phrase “at least one of”, when used with a list of items, means different combinations of one or more of the listed items may be used and only one of each item in the list may be needed. For example, “at least one of item A, item B, and item C” may include, without limitation, item A or item A and item B. This example also may include item A, item B, and item C or item B and item C.

In other words, network112may be comprised of a number of different networks that may be of the same type or different types. As depicted, a number of different types of devices may be used to form network112. For example, network112may include a number of different components that are configured to carry information114in network112. For example, network112may include routers, switches, computers, and communications links. Communications links117between components in network112may be implemented using at least one of wired links, optical links, wireless links, and other suitable types of media.

In one illustrative example, information114may be sent through communications network102from terminal devices119in platforms122over signals116to orbital portion104. In turn, information114may be relayed by satellites110in orbital portion104to the terrestrial portion106of communications network102. The information may then be further relayed through the ground system118and network112of terrestrial portion106to terrestrial users113in user terminal portion105.

In another illustrative example, information114may be sent through communications network102from terminal devices119in platforms122over signals116to orbital portion104. In turn, information114may be relayed by satellites110in orbital portion104to the terrestrial portion106of communications network102. The information may then be further relayed through the ground system118of terrestrial portion106over signals116to orbital portion104. The information114is further relayed by satellites110in orbital portion104to the terminal devices119in platforms122in the user terminal portion105.

In still another illustrative example, information114may be sent through communications network102from one of terrestrial users113in the user terminal portion105through the network112and the ground station118of the terrestrial portion106. The information may then be further relayed over signals116through the satellite110in orbital portion104to the terminals devices119in platforms122in the user terminal potion105.

Signals116may take various forms in communications network102. For example, signals116may be radio frequency signals. These radio frequency signals may be susceptible to jamming by intentional or unintentional sources of interference. In other illustrative examples, signals116may be optical signals, electrical signals, and other suitable types of signals.

In these illustrative examples, signals116form communications links117. Communications links117may include uplinks and downlinks. Uplinks are signals116that are transmitted from user terminal portion105or terrestrial portion106to orbital portion104. Uplink signals transmitted from the user terminal portion105are return uplinks. Uplinks from the terrestrial potion106are forward uplinks. Downlinks are signals116that are transmitted from orbital portion104to user terminal portion105or terrestrial portion106of communications network102. Downlinks to the terminal portion105are forward downlinks. Downlinks to the terrestrial portion106are return downlinks.

In this illustrative example, ground system118may be comprised of various components. As depicted, ground system118includes gateways120and control system121.

As depicted, gateways120in ground system118are configured to provide processing for signals116containing information114. For example, gateways120may perform processing of signals. This processing may include hopping, dehopping, permuting, depermuting, interleaving, encoding, decoding, switching, routing, and other suitable types of processing for signals116. Additionally, in some illustrative examples, gateways120may provide an interface between satellites110in orbital portion104of communications network102and different components in terrestrial portion106of communications network102.

For example, gateways120may provide an interface between satellites110and control system121. As another example, gateways120may provide an interface between satellites110, terrestrial users113, and network112.

In these illustrative examples, terminal devices119are hardware devices that process information114. The processing of information may include at least one of hopping, dehopping, permuting, depermuting, switching, encoding, decoding, switching, routing, using, generating, storing, and other suitable types of processing of information114. In some illustrative examples, terminal devices119may be configured to transmit, receive, or transmit and receive signals116with satellites110in exchanging information with satellites110.

As depicted, terrestrial users113are connected to network112. Terminal devices119also may be connected to network112in these illustrative examples. In other illustrative examples, terminal devices119may be remote to network112or otherwise unable to connect to network112. In this case, terminal devices119communicate with terrestrial users113via satellites110and ground system118.

When terminal devices119are connected to network112, terminal devices119may exchange information using network112. Being “connected to” network112does not imply that terminal devices119need to be physically connected to network112. In some cases, terminal devices119may only be intermittently connected to network112or may not be connected to network112at all depending on the particular implementation. In other illustrative examples, a terrestrial user in terrestrial users113or a terminal device in terminal devices119may be connected to network112indefinitely.

In these examples, terminal devices119may be associated with platforms122. Platforms122may take various forms. For example, a platform in platforms122may be selected from one of an aircraft, a surface ship, a ground vehicle, a submarine, a building, a spacecraft, a space station, a human operator, or some other suitable type of platform.

When one component is “associated” with another component, the association is a physical association in the depicted examples. For example, a first component, terminal devices119, may be considered to be associated with a second component, platforms122, by being secured to the second component, bonded to the second component, mounted to the second component, welded to the second component, fastened to the second component, and/or connected to the second component in some other suitable manner. The first component also may be connected to the second component using a third component. The first component may also be considered to be associated with the second component by being formed as part of and/or an extension of the second component. A first component may also be considered to be associated with a second component if the first component is carried by the second component.

Terminal devices119and terrestrial users113may be implemented using a number of different types of hardware. For example, a terminal device in terminal devices119, a terminal user in terrestrial users113, or both may be a computer, a tablet computer, a mobile phone, a laptop computer, or some other suitable device that is capable of processing information114. For example, a suitable device may be any device that has a processor unit. Further, terminal devices119, terrestrial users113, or both also may be configured to include hardware that allows terminal devices119and terrestrial users113to receive signals116.

As depicted, signal123in signals116is an example of a signal that may be used to exchange information114between satellites110in orbital portion104and components in user terminal portion105or terrestrial portion106of communications network102. In these illustrative examples, signal123may be frequency hopping signal124. Signal123may be implemented as frequency hopping signal124to avoid interference125. Frequency hopping signal124may take the form of a frequency hopping spread spectrum signal.

In these illustrative examples, interference125may be intentional, unintentional, or a combination of the two. When interference125is intentional, interference125may be generated to jam the transmission of signal123between user terminal portion105and orbital portion104in communications network102. In a similar fashion, interference125may be generated to jam the transmission of signal123between terrestrial portion106and orbital portion104in communications network102.

In other words, when interference125is intentional, interference125may be used to inhibit transmission of signal123to a destination location. For example, an adversarial user may attempt to jam signal123such that information114in signal123may not reach a destination location, cannot be extracted from signal123at the destination location, or some combination thereof.

By changing number of frequencies126in range of frequencies129for carrier waves127carrying information114in signal123, signal123takes the form of frequency hopping signal124. The changing of number of frequencies126over time may be referred to as frequency hopping.

In some illustrative examples, this change of number of frequencies126may merely be referred to as hopping. Hopping is implemented in a manner such that the transmitting and receiving equipment synchronously change number of frequencies126in a pattern known to the transmitter and receiver, but unknown to potential sources of interference125. This pattern appears pseudorandom to potential sources of interference125. This pattern is pseudorandom sequence130in these illustrative examples. In other words, the pattern is a predetermined pattern in the form of pseudorandom sequence130that is selected ahead of time before the transmission of information114. Thus, with the pattern being known only to the transmitter and receiver of frequency hopping signal124, a reduction in interference125may occur.

In particular, with the use of frequency hopping signal124, interference125is unable to change frequencies in the same manner at the same time as frequency hopping signal124. As a result, the effects of interference125may be reduced or avoided when signals116are exchanged between orbital portion104and at least one of user terminal portion105and terrestrial portion106of communications network102using frequency hopping signal124. In particular, frequency hopping signal124may reduce interference125when frequency hopping signal124is used to send information114between and among terminal devices119, gateways120, and terrestrial users113, using satellites110.

As depicted, information114is extracted from frequency hopping signal124by knowing the values for number of frequencies126at the different points in time. This process of extracting information114from frequency hopping signal124may be referred to as frequency dehopping. In other illustrative examples, the process may merely be referred to as dehopping.

With currently available satellite communications systems, dehopping of frequency hopping signal124is performed in satellites110in orbital portion104of communications network102. Performing dehopping of frequency hopping signal124in satellites110requires the use of processing resources in satellites110. In other words, with some currently available satellite communications systems, components and processor units needed to perform complex signal processing operations are located onboard satellites110in orbit.

With an illustrative embodiment, however, the processing of signal123carrying information114in the form of frequency hopping signal124exchanged between terminal devices119in platforms122, terrestrial users113, and ground system118is performed in terrestrial portion106of communications network102. In particular, hopping and dehopping of signal123may be performed by ground system118instead of satellites110.

Hopping, dehopping, or both hopping and dehopping of frequency hopping signal124may be performed by at least one of gateways120and control system121in ground system118. Other processing operations such as permuting, depermuting, interleaving, encoding, decoding, switching, routing, and other suitable types of processing also may be performed in terrestrial portion106of communications network102instead of being performed by satellites110in orbital portion104of communications network102.

As a result, processing resources in satellites110are not needed to perform at least one of hopping or dehopping of frequency hopping signal124. Instead, satellites110may relay signal123to terrestrial portion106of communications network102. The hopping and dehopping of signals116are performed by different components in terrestrial portion106of communications network102.

Thus, resources in satellites110may be made available for other uses. Further, the amount of equipment needed for satellites110may be reduced. As a result, the size, weight, complexity, and cost may also be reduced for satellites110. Moreover, refurbishment or replacement of satellites110is not needed to provide capabilities for performing hopping and dehopping of signal123.

In these illustrative examples, when frequency hopping signal124is transmitted over number of frequencies126, number of frequencies126may be changed in a random or pseudorandom manner. Number of frequencies126may be changed such that number of frequencies126is within range of frequencies129. Range of frequencies129may be wideband frequencies in these illustrative examples. In other words, the satellite communication system may use wideband frequency hopping signals to provide anti-jam protection from interference125.

For example, this change in number of frequencies126for channel128may be based on pseudorandom sequence130. In this case, a frequency for frequency hopping signal124may be changed over time in a pseudorandom manner. Pseudorandom sequence130may be used to identify information114carried in frequency hopping signal124. In particular, pseudorandom sequence130may be number of frequencies126at a particular point in time.

In these illustrative examples, transmission security generator132is configured to generate pseudorandom sequence130. Pseudorandom sequence130is used to change number of frequencies126in frequency hopping signal124. In other words, pseudorandom sequence130is used to perform hopping and dehopping of frequency hopping signal124. For example, gateways120may use pseudorandom sequence130to select number of frequencies126for hopping or dehopping frequency hopping signal124. In a similar fashion, terminal devices119also may use pseudorandom sequence130for hopping or dehopping frequency hopping signal124.

In these illustrative examples, at least one of the generation, storage, and distribution of pseudorandom sequence130may be managed by control system121. For example, a centralized control system121may distribute pseudorandom sequence130to gateways120for use in hopping and dehopping operations. Pseudorandom sequence130may be a pseudorandom noise code in these illustrative examples.

Further, when satellites110do not perform either dehopping or hopping of signals116, pseudorandom sequence130is not sent to satellites110. As a result, increased security may occur with respect to hopping and dehopping of signals116.

As depicted, control system121may be configured to manage the operation of one or more of gateways120and satellites110. In these illustrative examples, control system121is located on Earth108connected to network112in terrestrial portion106of communications network102. Control system121, when located on Earth108, may be connected to network112. In this illustrative example, control system121may be implemented using hardware, software, or a combination of the two.

In this example, control system121is configured to control the operations of one or more gateways120. Control system121includes a centralized resource controller to control the allocation of resources in gateways120. Control system121also includes centralized control of operation of gateways120. With the use of control system121, multiple gateway sites are feasible for gateways120and multiple wideband beams are enabled on a single satellite in satellites110. In other words, the efficiency of an illustrative embodiment allows for greater communications capabilities over a wider range of frequencies.

The common control system121allows for centralized resource control database and eliminates the need for synchronizing multiple distributed databases. In other words, the common control system121enables cost efficiencies in the implementation of the illustrative embodiment. In these illustrative examples, control system121may configure a satellite in satellites110with commands based on requests from terminal devices119in platforms122received over the air through satellite110and gateways120or from terrestrial users113received over network112.

As depicted, control of satellites110by control system121may be performed using control information134. Control information134may be sent to satellites110through signals116. Alternatively, control information134may be sent to satellites110by any other means that provide a desired level of security for the transmission of control information134in these illustrative examples. As an example, if gateways120include antennas in sanctuary locations, control information134may be sent in an alternative frequency band without frequency hopping.

In these illustrative examples, sanctuary locations may be locations with a desired standoff distance from potential jammers. In other words, a sanctuary location may be a location in which a jammer cannot physically approach the sanctuary location to jam signal123as signal123is transmitted to a destination location. In other illustrative examples, sanctuary locations may be selected based on the level of security present in that location. For example, with military communications, sanctuary locations may be remote locations within allied countries. Of course, sanctuary locations may be other suitable locations, depending on the particular implementation. Thus, if antennas transmitting control information134are in sanctuary locations where interference125cannot occur, hopping and dehopping of signal123with control information134may not occur.

In one illustrative example, control system121may be configured to control the operation of satellites110by sending control information134in signals116. Control system121may send a command in control information134to position an antenna on one of satellites110. In this instance, control system121may send a command in control information134in response to requests from terminal devices119received over the air through satellites110and gateways120. In another illustrative example, control system121may send a command in control information134in response to requests from terrestrial users113received over network112.

In these depicted examples, the use of an illustrative embodiment allows for the transmission of control information134in a manner that may be less likely to be jammed by interference125when sent using frequency hopping signal124. Further, processing of control information134may occur in terrestrial portion106of communication network102.

Thus, with the use of an illustrative embodiment to process signals116, at least one of the size, weight, complexity, and cost of satellites110may be reduced by performing dehopping and rehopping of signals116at locations other than satellites110.

Turning next toFIG. 2, an illustration of a block diagram of resources in a satellite is depicted in accordance with an illustrative embodiment. Satellite200is an example of an implementation for a satellite in satellites110inFIG. 1.

Power system210provides power to operate components within satellite200. Propulsion system212is configured to make changes in the orientation or position of satellite200.

Thermal control213is configured to control the temperature of different components in satellite200. Thermal control213may cool, heat, or heat and cool components, depending on the particular component.

Systems control214provides attitude control and coordination between all the systems in satellite200. Telemetry and command215is configured to monitor and direct other systems in satellite200. Telemetry and command215may identify the status of these systems.

In payload208, sensor system216may be implemented with different types of sensors configured to gather data. For example, sensor system216may include a telescope, a camera, and other suitable types of sensors.

As depicted, transponder system217is connected to antennas222. Transponder system217includes number of transponders228. Transponder232in number of transponders228is configured to send a signal in response to receiving a signal in these illustrative examples. Transponder232includes receiver234and transmitter236. In these illustrative examples, transponder232is configured to receive signals over a range of frequencies and retransmit those signals over the same or different range of frequencies to another location.

In these examples, receiver234is configured to receive signals from antennas222while transmitter236is configured to transmit these signals over antennas222. The transmission and reception of signals may occur over one or more of antennas222in these illustrative examples.

Transceiver system218is comprised of number of transceivers238. In this example, transceiver240in number of transceivers238is comprised of receiver242and transmitter244. Receiver242may receive signals while transmitter244transmits signals. The transmission of signals is not necessarily generated in response to the reception of signals by transceiver240in these illustrative examples. In these examples, receiver242is configured to receive signals from antennas222while transmitter244is configured to transmit these signals over antennas222. The transmission and reception of signals may occur over one or more of antennas222in these illustrative examples.

As depicted, receiver234in transponder232in satellite200is configured to receive signal123having range of frequencies129in which information114is carried in channel128having number of frequencies126within range of frequencies129inFIG. 1. Transmitter236in transponder232in satellite200is configured to transmit signal123to a remote location. Transmitter236is configured to transmit signal123when signal123is unprocessed to identify channel128used to carry information114by satellite200. In other words, when signal123is a wideband frequency hopping signal, signal123, may not be narrowband filtered before transmitter236re-transmits signal123.

In a similar fashion, signal123, when received by receiver242in transceiver240in satellite200, is not dehopped. Signal123also is not rehopped when retransmitted by transmitter244in transceiver240in these illustrative examples.

In this example, number of computers246is configured to receive commands and send data in information114. Number of computers246may be located in platform204, payload208, or both platform204and payload208.

In some illustrative examples, satellite200may also include a beacon generator coupled to the transmitter. The beacon generator may generate a beacon signal that is multiplexed with signal123for transmission by transmitter236. This signal includes beacon information, which may be used for a variety of purposes in these illustrative examples. For example, the beacon information in the beacon signal may be used for synchronization, security, and other suitable purposes. In particular, the beacon signal can be detected by multiple ground stations118so that the relative distance between the satellite and the various ground stations can be determined. In this way the ground stations can adjust their local time base so that terminals119synchronized by different ground stations118arrive at the satellite110at the same time. This ensures that frequency hopped signals124generated by terminals119do not interfere with each other.

In other words, dehopping and rehopping is not performed by the components in satellite200or payload208in these illustrative examples. For example, satellite200does not perform dehopping or rehopping when receiving and transmitting signals. Without performing these functions, the amount of resources that may be used in satellite200may be reduced.

In some illustrative examples, a portion of signal processing may still occur onboard satellite200. For example, dehopping of signal123may be performed onboard satellite200, but not other signal processing functions such as depermuting, demodulation, decoding, switching and routing, or other signal processing functions. Dehopping the signals onboard the satellite110may enable use of less frequency spectrum for the transmission of information114between the satellites110and the ground system118. Dehopping on the satellite110may furthermore improve the link efficiency and the anti-jam communications performance of the system.

In this case a beacon signal may be transmitted by the satellite110to enable the ground station118to accurately range the satellite110in order to synchronize the time base used on the satellite110for hopping and with the time base used in the ground station118and the terminals119for hopping.

Further, satellite200may also perform a digital channelizing function onboard satellite200before signal123is transmitted to a destination location in these illustrative examples. In this case, satellite200may very efficiently pack the frequency spectrum utilized between the satellite200and ground station118. The digital channelization function after dehop furthermore allows the gain and/or transmit power in the satellite200for each dehopped signal to be individually controlled. The channelizer may control gain and/or transmit power for each individual frequency hop and/or channel. This minimizes or eliminates the effect of strong signals or interference or jamming robbing power from weaker signals in the satellite transmitter. In this case, the components needed to perform dehopping, or both dehopping and channelizing do not add as much weight and complexity to satellite200as compared to performing more complex processing or full processing of signal123on satellite200.

In other words, with the use of an illustrative embodiment, satellite200can function by sending and receiving signals without performing dehopping and hopping, or by sending and receiving signals with dehopping, or with dehopping and channelizing, depending on the particular implementation. Further, number of computers246may process commands to cause operations to be performed using different resources in at least one of platform204and payload208. In this manner, a desired level of processing of signal123may be completed using components in communications network102inFIG. 1.

In some illustrative examples, transponder system217may also include at least one second transmitter to transmit a second wideband frequency hopping signal to a non-orbital receiver or to a second non-orbital receiver concurrently with transmitter236retransmitting signal123to the non-orbital receiver. For example, transmitter236may transmit signal123using a first polarization received from one coverage area, the second transmitter may transmit the second wideband frequency hopping signal received from a second coverage area, using a second polarization that is orthogonal to the first polarization. When a component is orthogonal to another component, the two components are perpendicular to one another.

Signal123and the second wideband frequency hopping signal may be power balanced. Signal123and the second wideband frequency hopping signal additionally may occupy orthogonal frequency hopping channels.

Thus, satellite200and ground station118may enable anti-jam protected communication from multiple coverage areas serviced by satellite200. Receiver234and transmitter236may be components of a relatively simple, low cost transponder, such as transponder232. For example, satellite200may be a commercial satellite and transponder232may be hosted onboard the commercial satellite. Transponder232may enable wideband frequency hopping communication in multiple frequency bands, such as a Ka band and an extremely high frequency (EHF) band.

Turning now toFIG. 3, an illustration of a block diagram of a gateway is depicted in accordance with an illustrative embodiment. Gateway300is an example of a gateway that may be located in gateways120inFIG. 1. In this illustrative example, gateway300includes communications processor302, transceiver system303, antenna system304, and network interface306.

Communications processor302is hardware and may include software. Communications processor302includes information director308, signal processor310, and synchronizer311. As depicted, communications processor302is configured to manage and process information received through gateway300. This information may be received through at least one of antenna system304and network interface306.

Information director308in communications processor302is configured to control the flow of information between antenna system304and network interface306. As depicted, information director308may be a router, a switch, or other suitable types of devices for controlling information flow.

In these illustrative examples, information director308may direct information received from terminals119through antenna system304to different destination terminals119using antenna system304or terrestrial users113using network interface306. In a similar fashion, information received from terrestrial users113through network interface306may be directed to different terminals119through antenna system304by reconfiguring or selecting number of satellite dishes312. Transceiver system303transmits the information in signals over number of satellite dishes312.

In this illustrative example, signal processor310is located in communications processor302and is configured to process signals. As depicted, signal processor310may be configured to perform hopping and dehopping of signals with respect to signals received by transceiver system303or transmitted by transceiver system303through antenna system304.

In other illustrative examples, signal processor310may also use beacon information318to synchronize gateway300with one or more additional gateways in gateways120, or to synchronize gateway300with one or more satellites in satellites110, for auto-tracking, or for a combination thereof. In the case where the satellites110are not hopping, the beacon is used to synchronize gateway300with one or more additional gateways in gateways120to ensure that terminals119synchronized to different gateways120are synchronized when they reach the satellite and do not interfere with each other. In the case where the satellites110are hopping, the beacon is used to track the range of satellites110and synchronize the hopping of satellites110with the gateway300.

In particular, the dehopping of the satellite return uplink must be advanced synchronously relative to the processing at the gateway of the same signal. Similarly the hopping of the satellite forward downlink must be retarded synchronously relative to the processing at the gateway of the same signal. In both cases, synchronization is maintained in the presence of satellite motion by aid of the beacon signal. In both cases, furthermore, gateway300may include or be coupled to an antenna autotracking system. The antenna autotracking system may use beacon information318or information derived from a beacon signal to track the satellite-based transmitter. The beacon information may include a pseudorandom noise code such as pseudorandom sequence130, a ranging sequence, other information, or a combination thereof.

As depicted, transceiver system303is configured to receive and send signals through antenna system304. In particular, transceiver system303may send received signals using number of satellite dishes312. In this example, transceiver system303is comprised of receiver system314and transmitter system316. A transceiver may include one or more receivers in receiver system314and one or more transmitters in transmitter system316.

In these illustrative examples, signal processor310may be configured to generate signal123with range of frequencies129in which carrier waves127carries information114and has number of frequencies126in channel128such that number of frequencies126inFIG. 1changes over time. In these illustrative examples, signal123may be a wideband frequency hopping signal. This wideband frequency hopping signal may be transmitted using antenna system304.

Further, signal processor310also may receive a frequency hopping signal and identify the information in the frequency hopping signal. In other words, gateway300also may perform dehopping. The dehopping signal may form a processed signal which is then transmitted to one of terrestrial users113through network interface306. In this case, frequency hopping may not be performed on the processed signal. In other illustrative examples, the information may be placed into another frequency hopping signal and retransmitted over antenna system304to platforms122and terminal devices119via satellites110.

In this illustrative example, the signal generated or processed by signal processor310may take various forms. For example, signal processor310may handle an extended data rate (XDR) waveform as well as other types of waveforms in generating and receiving signals. Signal processor310may include other signal processing functions in addition to the hopping and dehopping functions. When signals are received by gateway300, signal processor310may perform depermutation, demodulation, deinterleaving, decoding, decryption of orderwires or communications information, deframing, descrambling, despreading, interference mitigation, geolocation, adaptive nulling, or other suitable signal processing functions.

In other illustrative examples, signal processor310in gateway300may perform time-sensitive time synchronization acquisition and tracking processing. An “orderwire message” may be a message that is exchanged among terminals119and the resource control system408in the control system400for the purpose of allocating system resources, such as satellite antennas222and time and frequency allocations for communication circuits, synchronization probes, and orderwire messages, and other system resources. When signals are transmitted by gateway300, signal processor310may perform permutation, modulation, interleaving, coding, encryption of orderwires or communications information, framing, scrambling, spreading, spectral suppression, or other suitable signal processing functions.

Further, the extended data rate waveform, or any other waveform, may be fully processed by signal processor310to include more efficient types of demodulation and decoding. For example, signal processor310may perform soft-decision demodulation and decoding. Soft-decision processing may be desirable because soft-decision processing requires less signal-to-noise ratio than other types of decoding. With the use of less signal-to-noise ratio through soft-decision processing, data rate may be increased compared to performing hard-decision demodulation onboard satellite200inFIG. 2. As a result, performance of communications network102may be enhanced with the use of signal processor310in gateway300instead of a signal processor onboard satellite200.

Network interface306may be an interface to a network such as network112inFIG. 1. Network interface306may be an interface to a ground based wired network, a wireless network, an optical network, a synchronous optical network (SONET), or some other suitable type of network. Of course, the signal may be transmitted using various protocols such as an internet protocol or other type of digital communications protocol. In these illustrative examples, gateway300may use network interface306to transmit content of the processed signal to a terrestrial device113.

By including network interface306in gateway300, communications network102enables platforms122with terminal devices119to connect to terrestrial users113through network112without requiring terrestrial users113to have terminal devices119to connect to satellites110. In other words, communications between platforms122and terrestrial users113may be sent through network112such that terrestrial users113do not need capabilities to transmit information to satellites110.

In these illustrative examples, network interface306may be implemented using a number of different devices. For example, network interface306may be implemented using one or more network interface cards.

Synchronizer311in communications processor302may perform a number of different functions. In these illustrative examples, communications processor302with synchronizer311may be configured to perform synchronization functions with the use of information from control system121inFIG. 1.

In these illustrative examples, synchronizer311may perform different types of synchronization functions for gateway300. For example, synchronizer311may be used to calculate ranging measurements based on the time it takes for a signal to reach a satellite and be transmitted back to gateway300.

These ranging measurements may be stored in a database and/or may be sent to control system121inFIG. 1for further processing. Once control system121receives ranging measurements from gateway300and the other gateways in communications environment100, control system121may send instructions to synchronizer311to adjust its relative time.

The adjustment of the time to be synchronized between gateways120as well as other components such as satellites110and terminal devices119in communications network102may be used in hopping and dehopping signals116. Pseudorandom sequence130may be used to select a frequency for carrier wave127in signals116. If the time is not correct, then at some point in time the particular frequency selected by one gateway in gateways120may be different from other gateways in gateways120. As a result, carrier waves127containing information114from different terminals synchronized to different gateways120may interfere with each other at satellite200. The various signals cannot be guaranteed to be hopping on orthogonal frequencies without an accurate synchronization of time between the different components in communications environment100.

In these illustrative examples, these synchronization processes and other types of synchronization processes may be performed using beacon information318generated and broadcast by satellites110. Beacon information318broadcast by satellites110may contain a pattern used for identification. The time of arrival of beacon information318may be recorded locally by each of gateways120and compared to a common local calibrated time standard. This common local calibrated time standard may be Coordinated Universal Time (UTC) or other suitable time standards.

In these depicted examples, control system121collects times from each of gateways120to determine the distance from a satellite in satellites110to each gateway in gateways120. Control system121then sends commands to each of gateways120to synchronize gateways120.

In this manner, relative range between gateways in gateways120can be determined without reliance on any uplink transmissions from any of gateways120which may be subject to interference125. In other words, relative timing between gateways120can be determined without the need for each of gateways120to send an uplink to satellites110.

With the use of beacon information318, gateways120may be synchronized in these illustrative examples such that the flight time of signals116is the same for each of gateways120. In particular, synchronizer311may synchronize gateway300with other gateways120in communications network102. In other illustrative examples, such as in the case where the satellites110are hopping, the beacon is used to track the range of satellites110and synchronize the hopping of satellites110with the gateway300. In particular the dehopping of the satellite return uplink must be advanced synchronously relative to the processing at the gateway of the same signal. Similarly the hopping of the satellite forward downlink must be retarded synchronously relative to the processing at the gateway of the same signal. In both cases, synchronization is maintained in the presence of satellite motion by aid of the beacon signal.

In other illustrative examples, synchronizer311may adjust the time in gateway300based on information received from satellites110without receiving commands from control system121. In other words, synchronizer311may synchronize gateway300based on relative time calculated by gateway300or commands received from control system121in these illustrative examples.

Gateway300may additionally fully process the extended data rate (XDR) waveform, including forward error-correction encoding and decoding, and channel interleaving and de-interleaving, in addition to modulation and demodulation customarily performed at an XDR switch.

Gateway300may additionally, or in the alternative, host other anti-jam waveforms with enhanced waveform features such as bandwidth-on-demand, adaptive coding and modulation, bandwidth efficient modulation, beam handover, label switching, packet switching, resilience to blockage environment, some other suitable processes, or some combination thereof.

Transmitter system316may include a transmitter to transmit content of the processed signal to terminals119in multiple coverage areas under satellites110. For example, the transmitter of gateway300may be configured to wideband frequency hop signals for one coverage area under satellite200using one orthogonal polarization while and to simultaneously wideband frequency hop a second wideband frequency hopping signal for terminals119a second coverage area under satellite200.

Thus, gateway300enables anti-jam protected communication using relatively low cost satellite-based transponders to relay wideband frequency hopping signals. In this manner, satellite200may be less complex and costly and may utilize fewer resources202inFIG. 2than when processing is performed onboard satellite200. As a result, communications network102will also be less costly. Additionally, by performing the full-processing in a cost-effective manner in the gateway300and other gateways in gateways120inFIG. 1, communications performance is significantly improved relative to some currently used systems in which only partial processing is performed prior to switching. The wideband frequency hopping signals may be fully processed by gateway300rather than onboard the satellite reducing cost and lead time associated with providing satellite-based systems to dehop and fully process the wideband frequency hopping signals.

Turning now toFIG. 4, an illustration of a block diagram of a control system is depicted in accordance with an illustrative embodiment. In this depicted example, control system400is an example of a control system that may be used to implement control system121inFIG. 1.

In these illustrative examples, control system400includes a number of different components. As depicted, control system400includes mission control system402and the resource control and mission planning database413. The mission control system402is comprised of payload control system404, mission planning system406, resource control system408, health management system410, key management system416, transmission security generator418, and synchronization system422.

Mission control system402is configured to generate control information412. In these illustrative examples, control information412may be configuration information and may include commands, data, key material such as transmission security information or encryption keys, and other suitable information for controlling gateways120and one or more satellites110inFIG. 1. In some examples, control information412may include configuration information required by the terminal devices119to ensure compatible communications across communications network102inFIG. 1.

In this manner, mission control system402provides a centralized control of satellites110that may be operated by different entities. Mission control system402is responsible for the control functions for communications network102which may include control of at least one of platforms122, the payload208, gateways300, terminals119, terrestrial users113, the network112, and other suitable components.

Mission planning system406may be configured to set aside resources within communications network102for use by terminal devices119. For example, mission planning system406may make sure that sufficient communications resources are present for desired performance of communications network102for the particular needs of a user.

In one illustrative example, a user may require knowledge of system broadcast, acquisition, and logon resources, and may require knowledge of network compatible keys. The user may also require a desired number of bits-per-second, a number of terminals devices with desired features, and other parameters for desired performance of communications network102. With the identification of the desired number of bits-per-second and number of terminal devices with desired features as well as other parameters, mission planning system406may select terminal devices119, gateways120, satellites110, antennas222, as well as other resources for transmitting information114as desired, such as time and frequency slots for communications, synchronization, and orderwire messaging, as well as other resources. In other words, mission planning system406may plan communications network102and resources such that the desired connectivity, functionality, and level of performance are achieved.

Resource control system408may activate resources in gateway300to send signal123or signals116to satellites110inFIG. 1. For example, resource control system408may allocate transceivers within transceiver system303and satellite dishes in number of satellite dishes312to send signal123or signals116to satellites110. Resource control system408may process order wire messages between terminals119and gateway300in order to activate system resources, such as satellite antennas222and time and frequency allocations for communication circuits, synchronization probes, and orderwire messages, and other system resources. Resource control system408may be implemented using hardware, software, or a combination thereof.

In this illustrative example, resource control system408may control resources for the entire fleet of satellites110and associated gateways120. In this manner, resource control system408provides centralized control for network resources, satellite resources, and gateways resources for communications network102. Thus, the design of communications network102is streamlined and costs are reduced relative to a communications network with a distributed database which requires another layer of communication in order to maintain synchronization between components in the distributed databases.

Additionally, resource control system408processes messages received from and destined to terminals119serviced by the entire constellation of satellites110and gateways120. Processing may include authentication, parsing, formatting, encrypting, decrypting, and other suitable processing of inbound and outbound orderwire messages.

In other words, mission planning system406, resource control system408, or both may be configured to control reservation of satellite communication resources and activation of the satellite communication resources. Resource control system408and mission planning system406may communicate with at least one gateway in gateways120inFIG. 1. Resource control system408and mission planning system406may be centralized and remotely located from gateways120.

A centralized resource control system408and mission planning system406may be used to manage a plurality of satellite transponder systems. In this example, a first transponder is associated with a first gateway device in gateways120and a second transponder is associated with a second gateway device in gateways120. The first gateway device and the second gateway device do not communicate directly with one another via a satellite crosslink or terrestrial means to coordinate resource control and mission planning.

In another illustrative example, resource control system408may activate, upon receipt of a validated orderwire message, resources which have been previously identified, allocated, and reserved in mission planning database413by mission planning system406. Resource control and mission planning database413may store resource control and mission planning information related to a plurality of satellite transponder systems that facilitate communications between the one or more of terminal devices119.

In these illustrative examples, mission control system402may perform mission planning and resource control using a common resource control and mission planning database413. Resource control and mission planning database413identifies resources in communications network102inFIG. 1that have been allocated for various uses. For example, resource control and mission planning database413may identify satellites in satellites110and gateways in gateways120that have been allocated for use in transmitting information114inFIG. 1.

Transmission security information420is information used to provide a desired level of security for communications network102in these illustrative examples. Transmission security information420is information that may be generated at transmission security generator418and distributed to gateways120. For example, transmission security information420may include, for example, without limitation, keys that are used for hopping, permuting, rotation, cover, and other cryptographic functions. This function may also encrypt and decrypt secure orderwire messaging.

In this depicted example, transmission security generator418is an example of transmission security generator132depicted inFIG. 1. Transmission security generator418is a transmission security device that is certified and engineered from a trusted source. This trusted source may be the government, a security agency, or some other suitable source.

In these illustrative examples, control system400may transmit transmission security information420to gateways120. Transmission security information420may be used to provide a desired level of security for the communication of information114. This desired level of security may involve avoiding interference125, avoiding unintended parties seeing information114, and other security parameters. In order to protect transmission security information420, transmission security information420may be relayed by encrypted transmissions such as High Assurance Internet Protocol Encryptor transmission (HAIPE) or other suitable methods. Transmission security information420may be encrypted or protected by other suitable methods.

In other illustrative examples, transmission security generator418may be implemented in gateways120rather than in control system400. Placing transmission security generator418in gateways120may be used to expedite receipt of transmission security information420by gateways120or for other suitable reasons, depending on the particular implementation.

In these illustrative examples, mission control system402generates transmission security information420used by gateway300inFIG. 3. With the generation of transmission security information420, mission control system402may control the level of transmission security used when transmitting signals116in communications environment100inFIG. 1.

For example, mission control system402may provide gateway300with a key for hopping and dehopping signal123using signal processor310inFIG. 3. In these illustrative examples, the key may be pseudorandom sequence130inFIG. 1.

Mission control system402may also provide an interface between communications network102and an outside communications network. For example, a security establishment such as the National Security Agency may provide instructions for generating the key to be used in transmission security information420. That key is given to mission control system402for processing and sending to gateway300. In other words, mission control system402also provides a key management function for communications network102in these illustrative examples. The key management function may also manage keys and end cryptographic devices used by the terminals119in the communications network102.

Additionally, mission control system402may include a health management system410. Health management system410may monitor the health of control system400and other components in communications network102. Health management system410may be configured to automatically perform maintenance of components in communications network102, to generate alerts to perform maintenance of communications network102, or some combination thereof, depending on the particular implementation.

Payload control system404is configured to generate control information414. Control information414includes information used to control the operations of payload208in satellite200inFIG. 2.

Payload control system404may be used when satellite200functions as a host satellite. In this illustrative example, a host satellite may be a commercial satellite with multiple users. When satellite200functions as a host satellite, commands for operation of satellite200may flow through a commercial operator. In this case, a portion of control information414may be sensitive information and a portion of control information414may not be sensitive information. Payload control system404may add a level of security for the sensitive portion of control information414.

For example, this sensitive control information414may include positioning of antennas222on satellite200. Payload control system404secures the antenna pointing commands in control information414such that an operator of the host satellite may not be able to identify these antenna pointing commands.

In other words, payload control system404may be configured to send control signals in control information414to a transponder in a satellite via a gateway device, mission control system402, or both. The control signals may be used to control at least one of the elements in payload208. In an illustrative example, the control signals may include transponder gain or level control of transponders232, or antenna pointing commands used to control the pointing direction of antennas222of the transponder in satellite200.

In these illustrative examples, resource control system408may be configured to control resources in communications network102. For example, a terminal device in terminal devices119inFIG. 1may send an orderwire message asking control system400to turn on a particular communication service. As an example, a terminal device in terminal devices119may ask control system400to set up a point-to-point call. Resource control system408may be used by control system400to set up this point-to-point call and provide the communications resources necessary for the call.

In another illustrative example, resource control system408may send information about the state of communications network102to terminal devices119within communications network102. In still other illustrative examples, terminal devices119may ask for antennas to be pointed in a particular direction. This message is sent to resource control system408and resource control system408sends a repointing command to payload control system404for communication to satellite200. In some cases, when satellite200is a host satellite, payload control system sends the repointing commands.

Key management system416may be configured to send frequency hopping code information, other transmission security information, access control keys, and other pertinent key information to the one or more terminal devices119. The information sent by key management system416may be pseudorandom sequence130inFIG. 1. This information may also be transmission security information320inFIG. 3. The frequency hopping code information may be used by the one or more terminal devices119to determine a frequency hopping pattern of the wideband frequency hopping signals.

Key management system416in mission control system402is configured to generate information to provide security in the transmission of signals116. In particular, key management system416is configured to generate transmission security information320used by gateway300. For example, key management system416may be configured to generate information for frequency hopping. This information may include, for example, a pseudorandom number code such as pseudorandom sequence130. Additionally, key management system416also may generate encryption keys for encrypting information114, access control keys for terminal devices119, and other suitable types of information.

Synchronization system422may perform a number of different functions. In these illustrative examples, synchronization system422may be configured to provide synchronizer311inFIG. 3with information to synchronize gateway300and other gateways120inFIG. 1. Alternatively, in the case when hopping is performed on the satellite, the synchronization system422may be configured to synchronize hopping functions on the satellite110with hopping functions at the gateway120.

With the use of an illustrative embodiment, a centralized control system such as control system400allows communications network102greater flexibility and lower operational costs than with currently used communications networks. In contrast, with some currently used communications networks, control systems are decentralized such that more complex processing within each satellite occurs. This complex processing increases the cost and complexity of currently used communications networks.

Thus, with the use of an illustrative embodiment, however, control system400performs centralized security generation using transmission security generator418. Control system400also contains processing systems that work simultaneously for all of satellites110. As a result, the centralized control by control system400reduces overall system cost because processing and security functions are not needed on each of satellites110. Instead, control system400controls operation of all of satellites110in these illustrative examples.

Turning now toFIG. 5, an illustration of a signal is depicted in accordance with an illustrative embodiment. In this illustrative example, signal500is an illustration of one implementation for signal123inFIG. 1.

In this illustrative example, signal500may be wideband frequency hopped signal502. Signal500has range of frequencies504. Range of frequencies504is a range of frequencies in which information may be transmitted over time. Range of frequencies504may be a continuous range of frequencies or may be discontinuous. In other words, gaps may be present within the frequencies in range of frequencies504. In these illustrative examples, range of frequencies504may be a frequency hopping spread spectrum.

However, only a portion of range of frequencies504is used in any one instant of time to transmit information114inFIG. 1in these illustrative examples. For example, a transmitter using the wideband frequency hopping signals in range of frequencies504may divide a communication and send portions of the communication over different relatively narrow frequency bands. The order, timing, particular narrow frequency bands used for the communication, or some combination thereof may be determined based on a communication key.

As an example, channel506has number of frequencies508. As depicted, number of frequencies508may be continuous or may have gaps for channel506in these illustrative examples. Information114may be transmitted in channel506within range of frequencies504of signal500. In particular, a carrier wave may be used to carry information114in which the carrier wave has number of frequencies508in channel506.

As depicted, channel506in which information is transmitted may change over time as signal500is transmitted. Thus, at different points in time, channel506may have different values for number of frequencies508in which information114is transmitted. Two instants in time are illustrated inFIG. 5.

As number of frequencies508changes for channel506, this change may be referred to as frequency hopping or hopping of channel506. When frequency hopping or channel hopping occurs, signal500is considered to be a frequency hopping signal. This change or hopping of number of frequencies508may reduce the possibility of interference with the transmission of information114.

Additionally, signal500also may include beacon information318inFIG. 1. This beacon information may be sent in channel510which has number of frequencies512. In these illustrative examples, number of frequencies512for channel510may not change over time. Instead, beacon information318may be transmitted in signal500using fixed frequencies. Of course, in other illustrative examples, number of frequencies512for channel510also may change over time.

In this illustrative example, number of frequencies508in channel506may be considered to be a narrow band. Number of frequencies512in channel510also may be considered to be a narrow band. When a number of frequencies are a narrow band, the number of frequencies may have a range of about 1 KHz to 100 MHz depending on the particular implementation. Range of frequencies504may be considered to be a wideband range of frequencies. This range of frequencies may have a range that is about 1 GHz wide to about 2 GHz wide. The jam resistance of the transmission is approximately proportional to the ratio of the range of frequencies504to the number of frequencies508that are a narrow band and comprise the channel506.

In some illustrative examples, super high frequencies (SHF) or extremely high frequency (EHF) frequencies may be used. These frequencies range from about 3 GHz to about 300 GHz. In particular the 43.5-45.5 GHz and/or 30-31 GHz bands may be used for the return uplink and the 20.2-21.2 GHz band may be used for the forward downlink. Of course, yet other frequency ranges may be used depending on the particular implementation.

Although the frequencies are shown as being contiguous, those frequencies may be discontiguous depending on the functionality involved. In other words, range of frequencies504may have gaps in some cases.

Turning now toFIG. 6, an illustration of beam sizes for signals is depicted in accordance with an illustrative embodiment. In the different illustrative examples, signals116transmitted to and from satellites110inFIG. 1may be transmitted in the form of beams. These beams may have different sizes. In this illustrative example, beam sizes600are examples of beam sizes that may be used to send signals to and from satellite200inFIG. 2.

In these illustrative examples, beam sizes600include first beam size602, second beam size604, third beam size606, and fourth beam size608. First beam size602is about 1.5 degrees. Second beam size604is about 1 degree. Third beam size606is about 0.5 degrees and fourth beam size608is about 0.25 degrees.

As can be seen in this illustrative example, the distance at which a device is able to generate interference to jam signals changes based on the beam size. This distance may be referred to as a standoff distance.

Thus, as the beam size decreases for a beam used to transmit signal123inFIG. 1, the standoff distance at which a device may cause interference also decreases. In the different illustrative embodiments, interference with the transmission of signals116between satellites110and other devices may be reduced by a combination of frequency hopping and a selection of beam sizes. By decreasing the beam size, the ability of a device to cause interference with signals116in the beam is made more difficult because of the smaller standoff distance for the device as compared to a larger beam size.

Turning now toFIG. 7, an illustration of a block diagram of signals sent in a range of frequencies is depicted in accordance with an illustrative embodiment. As depicted, first signal700and second signal702are examples of signals116inFIG. 1that may be transmitted by satellite200inFIG. 2.

In particular, at least one of first signal700and second signal702may be wideband frequency hopping signals in these examples. In other words, first signal700may be a wideband frequency hopping signal, while second signal702is not a wideband frequency hopping signal. In another illustrative example, both first signal700and second signal702may be wideband frequency hopping signals.

In this depicted example, first signal700and second signal702are both transmitted using range of frequencies704. In other words, both signals use the same range of frequencies.

The same range of frequencies may be used through different polarization of first signal700and second signal702. For example, first signal700may have first polarization706, while second signal702has second polarization708.

In these illustrative examples, first signal700with first polarization706and second signal702with second polarization708may be power balanced. As depicted, first signal700may have a higher data rate than second signal702. In this case, first signal700may use more power than second signal702. In order to prevent first signal700from interfering excessively with second signal702, and to prevent second signal702from interfering excessively with first signal700, when the two signals are transmitted substantially concurrently, the two signals are power balanced in these illustrative examples. In other words, devices are in place in the communications network that ensure that first signal700and second signal702receive the appropriate level of power for desired transmission of these signals.

Further, first signal700with first polarization706and second signal702with second polarization708may use orthogonal frequency channels that are synchronously frequency hopped. In other words, first signal700and second signal702may be frequency hopped at the same time using pseudorandom sequence130inFIG. 1.

Further, first signal700with first polarization706and second signal702with second polarization708may be synchronously hopped wideband frequency hopping signals, which instantaneously hop to different number of frequencies508within the common range of frequencies504. In this way, interference between the first signal700on the first polarization706and the second signal702on the second polarization708is minimized.

With reference now toFIG. 8, an illustration of a block diagram of beacon information is depicted in accordance with an illustrative embodiment. In this depicted example, beacon information800is an example of beacon information318that may be transmitted in a beacon signal that may be part of signal123transmitted by satellite110inFIG. 1.

As an example, a gateway in gateways120may include a receiver to receive a beacon signal from a satellite-based transmitter. In these illustrative examples, the beacon signal may be multiplexed or integrated as part of signal123. The return downlink may include two or more signals with different polarizations. The return downlink signal may be a wideband frequency hopping signal of the satellite-based transmitter.

As depicted, beacon information800may be sent to various components in communications network102inFIG. 1. For example, beacon information800may be sent to gateways120, terminal devices119, and other suitable components inFIG. 1. In particular, the beacon signal may be multiplexed or integrated as part of signal123in these illustrative examples.

As depicted, beacon information800may include a number of different types of information. For example, beacon information800may include pseudorandom noise code806, timestamps802, and other suitable types of information. Beacon information800is used to aid in accomplishing at least one of autotracking a location of a satellite transmitting the beacon information by the antenna of terminal119or gateway120, maintenance of satellite master oscillator frequency syntonization by the control system121, synchronizing the gateway with other gateways, and, in the case of a frequency hopped satellite, synchronizing the gateways with the satellite.

Pseudorandom noise code806transmitted by satellites110may be used to synchronize gateways120to each other. The difference in time at which the pseudorandom noise code806is received at several gateways120may be used to determine the relative delay between the satellite110and the several gateways120. With this information the hopping time bases of the various gateways120may be adjusted so that hopping signals synchronized to the various gateways120are synchronized upon arrival at the satellite110. In this way all wideband hopping signals from the various gateways120and from terminals119synchronized to the various gateways120are synchronized at the satellite so that they do not interfere with each other.

In the case of frequency hopped satellites, timestamps802transmitted by the satellite110, together with the pseudorandom noise code806, may be further used to synchronize the frequency hopping satellite110with the frequency hopping gateways120. The time at which the information is received by the gateways120may be compared to the time stamp inserted by the satellite110in order to determine whether the satellite time base is early or late. In this manner, the satellite time base may be adjusted to synchronize the satellite with the gateway. Utilizing these satellite transmissions, all wideband hopping signals from the various gateways120and from terminals119synchronized to the various gateways120are synchronized at the satellite so that they do not interfere with each other. All wideband hopping signals associated with all gateway devices processing signals from transponders with overlapping fields of view on a common satellite are synchronized at the satellite to avoid frequency interference and to maintain frequency hopping orthogonality of the signals on those transponders.

Turning now toFIG. 9, an illustration of a block diagram of security information is depicted in accordance with an illustrative embodiment. In this illustrative example, transmission security information900may include pseudorandom sequence902, encryption key904, encryption algorithm906, signal processor908, and other suitable information.

In one example, transmission security information900may be a sequence of pseudorandom bits or a control key used to perform frequency hopping and dehopping functions, to perform time permutation and depermutation functions, to perform data cover and decover functions, or to perform other suitable transmission security functions by signal processor908in these illustrative examples. In other illustrative examples, transmission security information900may be instructions to randomize an order of transmission of signals116inFIG. 1or some other suitable type of transmission security information, depending on the particular implementation. These functions assure availability and confidentiality of information114in the presence of jammers or other threats.

As depicted, encryption key904and encryption algorithm906may be used to encrypt information114. The encryption of information may provide further security to protect availability and confidentiality of information114.

The illustration of communications environment100and the different components in communications environment100inFIGS. 1-9are not meant to imply physical or architectural limitations to the manner in which an illustrative embodiment may be implemented.

For example, control system121may be in another location such as in orbit or moving through space above Earth108inFIG. 1. As another illustrative example, satellite200may have other configurations in other illustrative examples other than the configuration shown inFIG. 2. For example, in some illustrative examples, satellite200may only include transponder system217and may not have transceiver system218. In another example, sensor system216may be omitted from payload208inFIG. 2.

With reference now toFIG. 10, an illustration of a communication of information in a communications environment is depicted in accordance with an illustrative embodiment. Communications environment1000is an example of one implementation for communications environment100shown in block form inFIG. 1.

In this illustrative example, gateway1008and mission control1014are connected to network1016. Network1016may be, for example, a wide area network, a local area network, the Internet, or some other suitable type of network.

Mission control1014is configured to provide management of various resources in communications environment1000. For example, mission control1014may control satellite1006, satellite1030, and gateway1008. In particular, mission control1014may manage resources in these components to provide communication connectivity among various terminal devices and between various terminal devices and terrestrial users in communications environment1000. In this illustrative example, mission control1014is configured to provide mission planning, resource control, gateway synchronization, payload control, health management, and other suitable types of functions depending on the particular implementation.

In this illustrative example, first terminal device1010is located on surface ship1018. Second terminal device1012is located on aircraft1020.

In this illustrative example, first terminal device1010may send information to second terminal device1012. When first terminal device1010sends information to second terminal device1012, first terminal device1010generates a wideband frequency hopping signal. First terminal device1010sends the information in the wideband frequency hopping signal to satellite1006and satellite1006retransmits the wideband frequency hopping signal to gateway1008as shown by path1022.

In turn, gateway1008is configured to dehop the wideband frequency hopping signal. In this case, gateway1008dehops the wideband frequency hopping signal to form a processed signal. Gateway1008transmits the processed signal as a wideband frequency hopped signal to a destination terminal device, second terminal device1012in aircraft1020.

In this illustrative example, the transmission of the processed signal to second terminal device1012passes through satellite1006as indicated by path1024. In other words, satellite1006receives the processed signal and retransmits the processed signal along path1024. In this particular example, the processed signal is a second wideband frequency hopping signal that is transmitted along path1024to second terminal device1012. Second terminal device1012is configured to dehop the second wideband frequency hopping signal to obtain the information in these illustrative examples.

As can be seen in this illustrative example, the processes for dehopping and hopping the signal, and for other signal processing functions such as demodulation, deinterleaving, decoding, switching, modulation, interleaving, and encoding, are not performed by satellite1006. As a result, the amount of equipment needed on satellite1006may be less than otherwise needed if processing where to occur on satellite1006. Further, the processing resources in satellite1006may be applied to other functions since dehopping and hopping and other signal processing functions are not performed by satellite1006.

Moreover, in these illustrative examples, a pseudorandom number sequence may be generated by mission control1014and distributed to gateway1008, first terminal device1010, and second terminal device1012for hopping and dehopping signals in these illustrative examples. The gateway1008or mission control1014also may manage the synchronization of first terminal device1010, and second terminal device1012, by means of exchange of sync signals between gateway1008and first terminal device1010and second terminal device1012.

In these illustrative examples, the synchronization may be achieved by means of exchange of sync signals between gateway1008and first terminal device1010and second terminal device1012through satellite1006and satellite1030. In other illustrative examples where a satellite1006has connectivity to multiple gateways1008, the gateways1008are synchronized to each other by means of a beacon broadcast by the satellite1006which contains a pseudorandom number code which can be used to determine relative path length between the satellite1006and the gateways1008. In yet further illustrative examples, where satellite1006performs frequency hopping and dehopping, satellite1006is synchronized to gateway1008by means of a beacon broadcast by the satellite1006which contains both a pseudorandom number code and a timestamp which can be used to track the absolute path length between the satellite1006and the gateways1008.

In this manner, the different components in communications network1001may perform frequency hopping using a pseudorandom number sequence at the appropriate times. In other words, the selection of a frequency using the pseudorandom number sequence may be made such that the correct frequency is selected for hopping and dehopping signals in these illustrative examples.

In another illustrative example, first terminal device1010may send information to terrestrial user1026. Terrestrial user1026is located in building1028in these illustrative examples. Terrestrial user1026is connected to network1016. When first terminal device1010sends information to terrestrial user1026, information may be transmitted along path1022to gateway1008.

In one illustrative example, gateway1008generates a processed signal, which does not take the form of a wideband frequency hopping signal. Instead, gateway1008may send the processed signal without performing hopping. Rather than performing hopping on the signal, the information may be transmitted in the processed signal through network1016.

In these illustrative examples, network1016may be a secured network and may take various forms. For example, network1016may be a ground based wired network, a wireless network, a synchronous optical network (SONET), an optical network, or some other suitable type of network. The transmission of information may be made using internet protocol or other digital communications depending on the particular implementation.

In yet another illustrative example, first terminal device1010may send information in the wideband frequency hopping signal through path1032instead of path1022. Path1032uses satellite1006and satellite1030. In this illustrative example, satellite1030first receives the wideband frequency hopping signal and retransmits the wideband frequency hopping signal in a cross-link to satellite1006. Satellite1006then sends the wideband frequency hopping signal to gateway1008. From this point, the wideband frequency hopping signal may be processed in a manner described above.

Thus, communication network1001enables anti-jam protected communication throughout the coverage area of a first transponder on satellite1006and possibly one or more additional transponders on satellite1030or other satellites in communications environment1000. The first transponder and any other transponders may be relatively simple, small and light weight devices. These types of devices may enable commercial satellites or other satellites to host the transponder, thereby reducing cost of the communication system.

Additionally, gateway devices, such as the gateway1008, may be located in sanctuary areas that can be protected from harm and from jamming. A sanctuary area may be an area with a desired level of security such that jamming may be prevented. A sanctuary area may be a remote location, a ground station, a complex, a military base, or some other area with a desired level of security.

Further, since gateway devices of communication network1001can communicate via terrestrial networks, other components of communication network1001, such as mission control system1014, a payload control system, a resource control system, a mission planning system, a resource control and mission planning database, a key facility, transmission security and communications security facilities, other components, or a combination thereof, may be collocated with gateway1008or may be located remotely from the gateway1008.

Moreover, communications can be received at gateway1008or routed from gateway1008over the terrestrial network eliminating or reducing the use of dedicated satellite communication user terminals at fixed installations such as command centers. Additionally, high security information and components can be more closely controlled and implemented with lower cost. For example, hardware and software to perform transmission security and communications security processing, such as frequency hopping and dehopping or orderwire message encryption and decryption, is not needed on satellites and can instead be located at protectable installations associated with gateway1008or mission control1014.

Turning now toFIG. 11, another illustration of a communications environment is depicted in accordance with an illustrative embodiment. Communications environment1100is an example of another implementation for communications environment100inFIG. 1.

In this illustrative example, message flow between components in communications environment1000is depicted. As depicted, communications environment1100is comprised of communications network1102. Communications network1102has orbital portion1104, user terminal portion1105, and terrestrial portion1106. Orbital portion1104of communications network1102includes satellite1108, satellite1110, and satellite1112.

In this example, user terminal portion1105of communications network1102includes first terminal device1120, terrestrial user1122, and second terminal device1124. Terrestrial portion1106includes internet protocol network1114, gateway1116, gateway1118, control system1126, user mission planning1128, key facility1130, host satellite operation control1132, and host satellite operation control1134.

In these illustrative examples, gateway1116, gateway1118, and terrestrial user1122are connected to internet protocol network1114. In this example, internet protocol network1114may provide for the exchange of information such as user data, inter-gateway communications, payload telemetry and command, resource control management commands, synchronization control information, transmission security information, and other suitable types of information.

As depicted, intergateway communications1150may be sent between gateway1116and gateway1118. User data1152may be sent from gateway1116to terrestrial user1122through internet protocol network1114. User data1154may be sent from gateway1118to terrestrial user1122through internet protocol network1114. User data1152and user data1154also may be sent from first terrestrial user1122to gateway1116and gateway1118, respectively.

Further, in these illustrative examples, mission control information1156may be sent between control system1126and at least one of gateway1116and gateway1118. This mission control information may then be sent to at least one of satellite1108, satellite1110, and satellite1112from at least one of gateway1116and gateway1118. This mission control information may then be further distributed to first terminal device1120and second terminal device1124. The information may be distributed to terrestrial user1122over internet protocol network1114through gateway1116and gateway1118.

In these illustrative examples, mission control information1156may include a number of different types of information. For example, mission control information1156may include at least one of payload telemetry and command, resource control management commands, synchronization control information, transmission security information, and other information.

In some illustrative examples, mission control information1156may be sent between control system1126and gateway1116using internet protocol network1114. Similarly, mission control information1156may be sent between control system1126and gateway1118using internet protocol network1114. When mission control information1156is sent from control system1126to gateway1116, gateway1118, or both, mission control information1156may be configuration and status data.

Intergateway communications1150between gateway1116and gateway1118may be sent via a transport service that provides constant delay with low levels of delay variation. Such a service may be a synchronous optical network in these illustrative examples. An internet protocol network, multiprotocol label switching, and other suitable types of services may also be used to send intergateway communications1150between gateway1116and gateway1118, depending on the functionality involved.

In this illustrative example, host satellite operation center1132may send satellite operation center information1158to control system1126. Additionally, host satellite operation center1134also may send satellite operation center information1160to control system1126. As another illustrative example, key facility1130may send transmission security information1162to control system1126. In another example, user mission planning1128may send planning information1164to control system1126. As can be seen, control system1126may use all of this information to generate mission control information1156for distribution to gateway1116and gateway1118as well as other components through these gateways.

Although the flow of information is described in only one direction in some of these examples in communications environment1100, information may flow in the other direction or in both directions depending on the particular implementation. For example, control system1126may return data or other information to host satellite operation center1132and host satellite operation center1134. As another example, control system1126may send requests to key facility1130with respect to the generation of transmission security information1162.

In this illustrative example, gateway1116and gateway1118in terrestrial portion1106, and first terminal device1120and second terminal device1124in user terminal portion1105may exchange signals1138with satellite1108, satellite1110, and satellite1112in orbital portion1104of communications network1102. The exchange of signals1138with satellite1108, satellite1110, and satellite1112may provide a medium to exchange information between gateway1116, gateway1118, first terminal device1120, and second terminal device1124.

In these illustrative examples, signals1138may be wideband frequency hopping signals used to avoid interference during the transmission of information between orbital portion1104and the terrestrial portion1106and user terminal portion1105of communications network1102.

In these illustrative examples, gateway1116and gateway1118provide an interface between control system1126and other components in communications environment1100. As depicted, gateway1116and gateway1118provide circuit termination with connectivity to a terrestrial network such as internet protocol network1114.

In this example, gateway1116and gateway1118are the components in which hopping and dehopping of signals1138are performed. In this manner, at least one of less weight, lower resource use, and less expense may occur with respect to satellite1108, satellite1110, and satellite1112. As a result, signals1138are not dehopped or hopped by satellite1108, satellite1110, or satellite1112in these illustrative examples. Instead, these satellites may retransmit signals without performing signal processing with respect to hopping or dehopping of the wideband frequency signals that are being transmitted in signals1138.

Further, at least one of gateway1116and gateway1118may each send information from control system1126to perform synchronization with satellite1108, satellite1110, and satellite1112to avoid interference with signals1138. This interference may be self-interference between users of the system.

In these illustrative examples, gateway1116and gateway1118are synchronized such that signals1138are accurately aligned in time. As a result of synchronization, signals1138will not collide with each other.

In this example, at least one of satellite1108, satellite1110, and satellite1112send beacon information to gateway1116and gateway1118. The beacon information contains a pseudorandom code with good correlation properties and of suitable length to resolve uncertainty in satellite range that may result from conventional ranging techniques.

Next, gateway1116and gateway1118record the time of receipt of the beacon information and transmit that time of receipt to control system1126. Control system1126then determines the difference in range from the satellite transmitting the beacon information to each of the gateways, based on the delay of the signal reaching each gateway. Based on the delay measurements, the mission control center1126identifies timing corrections for each of the gateways. The timing corrections are used to ensure that that signals1138are properly aligned at the payload to eliminate mutual interference. Control system1126sends instructions to gateway1116and gateway1118to adjust respective time so that terminals synchronized to one gateway can avoid interference with terminals synchronized to other gateways when transmitting and receiving signals1138.

In these illustrative examples, gateway1116and gateway1118also may provide synchronization processing. For example, gateway1116, gateway1118, or both may collect data from each gateway and determine timing correctly for each gateway such that signals1138are properly aligned. In this manner, mission control1126is not needed to synchronize gateway1116and gateway1118.

In this illustrative example, control system1126provides a centralized location for resource control, mission planning, key management, payload control, gateway synchronization, transmission security, and other suitable functions. In other words, control system1126provides a centralized location for information and control.

As depicted, host satellite operation center1132and host satellite operation center1134may send commands and requests to control system1126. In turn, control system1126sends control signals to satellite1108, satellite1110, and satellite1112to control the platform side of these satellites. User mission planning1128may generate commands to perform different operations with payloads in satellite1108, satellite1110, and satellite1112. Control system1126receives the commands and sends the commands to these satellites through gateway1116and gateway1118.

Key facility1130may store keys for secure transmissions. These keys may include, for example, at least one of a pseudorandom code, an encryption key, and other suitable types of information. Key facility1130may send this information for storage and distribution by control system1126in these illustrative examples.

Although the illustrative embodiments inFIG. 11are depicted with three satellites in orbital portion1104of communications network1102, any number of satellites may be used. For example, one satellite, five satellites, ten satellites, nineteen satellites, or some other suitable number of satellites may be present in orbital portion1104of communications network1102, depending on the particular implementation.

Turning now toFIG. 12, an illustration of a communications environment is depicted in accordance with an illustrative embodiment. In this depicted example, communications environment1200is an example of one implementation for communications environment100shown in block form inFIG. 1.

In this illustrative example, communications network1202in communications environment1200is configured to provide communication of information between different components. As depicted, communications network1202includes orbital portion1204, user terminal portion105, and terrestrial portion1206. In this example, satellite1208is located in orbital portion1204of communications network1202.

In this illustrative example, user terminal portion105is comprised of first terminal device1226, second terminal device1228, third terminal device1230, and fourth terminal device1232. Terrestrial portion1206of communications network1202is comprised of gateway1210, gateway1212, host telemetry and command1214, payload telemetry and command1216, deployed planning1218, master planning1220, key management system1222, key facility1224, network1234, and network1236.

As depicted, host satellite operations center1214is a ground facility for monitoring the status of and for the control of host satellite mission equipment. Host satellite operations center1214may be part of communications network1202or operated by a host of the payload. For example, when using a host satellite for communications, host satellite operations center1214may be operated by the owner of the host satellite.

In this illustrative example, payload control system1216is configured to control the operations of the payload. For example, payload control system1216may be configured to send control signals to satellite1208via gateway1210or gateway1212to control such functions on the payload208, such as the pointing of the antennas222.

In this example, deployed planning1218enables end users of the system to plan usage of the system and provides tools for end users to appropriately submit requests to mission planning system1220for communications services. In some embodiments, such deployed planning1218and associated tools may not be required, and all planning activities may be conducted directly by mission planning system1220.

As depicted, mission planning system1220allocates system resources in satellite1208, gateway1210, gateway1212, network1234, and network1236, and other system resources in support of user communication requests. System resources include control of antenna resources, allocation of frequency and time slot assignment for communications, for orderwire transmissions, and for synchronization transmissions, and for other system resources. Mission planning system furthermore directs configuration of satellite1208, gateway1210, gateway1212, network1234, network1236, first terminal device1226, second terminal device1228, third terminal device1230, and fourth terminal device1232, and other elements of the communication network1202in communication environment1200, in support of allocations to support user communication requests.

In these illustrative examples, key management system1222is configured to generate information to provide security in the transmission of signals. In particular, key management system1222is configured to generate transmission security information used by gateway1210and gateway1212. For example, key management system1222may be configured to generate information for frequency hopping. Additionally, key management system1222also may generate encryption keys for encrypting information, access control keys for at least one of first terminal device1226, second terminal device1228, third terminal device1230, fourth terminal device1232, and other suitable types of information.

Key management system1222interfaces with key facility1224to obtain key material. Key facility1224may provide the key for key management system1222to manage security of communications network1202. Key facility1224may generate new keys periodically in these illustrative examples.

As depicted, first terminal device1226is associated with ground vehicle1238. Second terminal device1228is associated with surface ship1240. Third terminal device1230is associated with surface ship1242and fourth terminal device1232is associated with surface ship1244.

In these examples, return uplinks to satellite1208from first terminal device1226, second terminal device1228, third terminal device1230, and fourth terminal device1232may use extremely high frequency signals, such as 43.5-45.5 GHz. Forward downlinks from satellite1208to first terminal device1226, second terminal device1228, third terminal device1230, and fourth terminal device1232may use super high frequency signals, such as 20.2-21.2 GHz. Forward uplink to satellite1208from gateway1210and gateway1212may use extremely high frequency signals, such as 30-31 GHz. Return downlink from satellite1208to gateway1210and gateway1212may use super high frequency signals, such as 18-20 GHz or 20.2-21.2 GHz.

Host satellite operations center1214may communicate with satellite1208using Kasignals1284. Kasignals1284are signals in a Kaband. Kasignals1284may have a frequency from about 26.5 GHz to about 40 GHz in these illustrative examples. Kasignals1284may be in the microwave band of the electromagnetic spectrum.

As depicted, satellite1208may exchange radio frequency signal path1246, radio frequency signal path1248, radio frequency signal path1250, radio frequency signal path1252, radio frequency signal path1254, and radio frequency signal path1256with gateway1210, first terminal device1226, second terminal device1228, third terminal device1230, and fourth terminal device1232, respectively.

Of course, communications with satellite1208may be performed using other types of signals, such as radio frequency signals in other frequency bands, or other suitable signals, in some illustrative examples.

Turning now toFIGS. 13A-13B, illustrations of a payload is depicted in accordance with an illustrative embodiment. In this illustrative embodiment there are four dual-frequency single-polarization independently steerable user pointed antennas forming four user spot beams which provide connectivity to user terminals at 43.5-45.5 GHz for the return uplink and 20.2-21.2 GHz for the forward downlink. Additionally there are two dual-frequency dual-polarization independently steerable gateway pointed antennas forming two gateway spot beams which provide connectivity to the gateways at 30-31 GHz for the forward uplink and 18.2-20.2 GHz for the return downlink.

As depicted in the illustrative block diagram at the top ofFIG. 13Aand the illustrative frequency plan at bottom ofFIG. 13B, return link signals from user terminals are received at 43.5-45.5 GHz on the single polarization user spot beams, using right-hand circular polarization. These signals are low-noise amplified and then block down-converted to the 18.2-20.2 GHz return downlink band. Return link signals from two user spot beams are multiplexed together on each dual-polarization gateway spot beam, using both right-hand circular polarization and left-hand circular polarization. In this way four single-polarization 2 GHz wideband hopping return user uplink beams can be multiplexed onto two dual-polarization 2 GHz wideband hopping return gateway downlink beams.

Furthermore, as depicted in the illustrative block diagram at the top ofFIG. 13Aand the illustrative frequency plan at bottom ofFIG. 13B, forward link signals from gateways are received at 30-31 GHz on the dual-polarization gateway spot beams, using both right-hand circular polarization and left-hand circular polarization. These signals are low-noise amplified and then block down-converted to the single-polarization 20.2-21.2 GHz forward downlink band, and transmitted using right-hand circular polarization. Forward link signals destined for two user spot beams are multiplexed together on each dual-polarization gateway spot beam, using both right-hand circular polarization and left-hand circular polarization. In this way four single-polarization 1 GHz wideband hopping user forward downlink beams can be multiplexed onto two dual-polarization 1 GHz wideband hopping forward gateway uplink beams.

In this illustrative embodiment, the payload performs not hooping or dehopping of the wideband frequency hopping signals. The payload a simple wideband transponder for both the return link and the forward link.

Of course, in other illustrative embodiments, alternate numbers of user spot beams and gateway spot beams can be chosen, and alternate frequency bands and polarizations can be chosen. In other illustrative embodiments where satellite orbital slot and gateway sites are fixed, the gateway beams can be formed with a single fixed antenna with one or multiple feeds, rather than with independently steerable antennas, depending on the application.

Turning now toFIG. 14, another illustration of a payload is depicted in accordance with an illustrative embodiment. In this illustrative example, payload1400is an example of one implementation for payload208inFIG. 2. As depicted, payload1400is shown providing connectivity between terminal devices119and two gateways in gateways120inFIG. 1.

In these depicted examples, payload1400includes four dual-frequency single-polarization user pointed antennas1402. Each user pointed antenna in user pointed antennas1402receives return frequency hopped signals from terminal devices119within a coverage area of the antenna. This coverage area is a frequency directive coverage area in these illustrative examples. User pointed antennas1402also transmits frequency hopped signals originating at the gateway back to terminal devices119within the coverage area of the antenna.

As depicted, the coverage areas of user pointed antennas1402, the coverage areas of gateway-pointed antennas1404, or both may be achieved in a number of different ways. For example, the coverage areas may be achieved using a number of different types, quantities, and combinations of antenna feeds and reflectors. As an example, user pointed antennas1402and gateway pointed antennas1404may be at least one of a gimbal antenna, a gimbal dish, a multi-beam antenna, a phased array, an array fed reflector, or other suitable types of devices. These antenna feeds and reflectors may be fixed, electronically steered, mechanically steered, or moved in another suitable fashion. Additionally, multiple coverage areas may share the same antenna or antenna reflector in these illustrative examples.

In these depicted examples, the return frequency hopped signals are received by user pointed antennas1402and amplified by low-noise amplifiers1406. Low-noise amplifiers1406may be used to amplify the signal received from user pointed antennas1402to reduce losses in strength of the signal.

Next, the frequency hopped signals are down-converted by fixed local oscillator and filtered in fixed down-converters1408. In this step, down-converting is performed by fixed local oscillator without frequency dehopping the signals. Fixed local oscillator down-converts the signals to the transmit band which is equal in bandwidth to the receive band.

In these illustrative examples, the frequency hopped signals are then amplified by linearized high-power amplifier1410and transmitted to gateways120through gateway-pointed antennas1418. In this depicted example, two gateway pointed antennas are present in gateway pointed antennas1418. Of course, other numbers of antennas may be used. For example, one antenna, three antennas, six antennas, or some other suitable number of gateway pointed antennas may be used, depending on the particular implementation.

Before being transmitted through downlink ports1418of gateway-pointed antennas1404, the frequency hopped signals are multiplexed using multiplexer1412and multiplexer1414. Multiplexer1412and multiplexer1414multiplex the frequency hopped signals using polarization diversity. A beacon signal from beacon generator1416is also multiplexed with the frequency hopped signals. This beacon signal is used to aid in system syntonization and synchronization in these illustrative examples.

As depicted, the forward frequency hopped signals are received by gateway-pointed antennas1404. The signals are demultiplexed using demultiplexer1420and demultiplexer1422. Demultiplexer1420and demultiplexer1422demultiplex the frequency hopped signals using polarization diversity. Next the signals and amplified by low noise amplifiers1424.

Next, the signals are down-converted by fixed local oscillator and filtered by fixed down-converter1428, without frequency dehopping, to the transmit band which is equal in bandwidth to the receive band. The frequency hopped signals are then amplified by high-power amplifier1432and transmitted to terminal devices119through downlink frequency ports1434on user pointed antennas1402.

In this illustrative example, frequency hopped signals destined for two different user pointed antennas1434are multiplexed onto the same gateway pointed antenna feed using polarization diversity. All frequencies are locked to tunable master oscillator1417, which is controlled by mission control system402inFIG. 4. Master oscillator1417controls local oscillator in fixed down-converter1408and fixed local oscillator in fixed down-converter1428.

In some illustrative examples, payload1400may also include additional beacons to aid in terminal spatial acquisition of the satellite. Further, payload1400may also provide the flexibility to receive signals in one or more bands. For example, signals may be received both the EHF band, about 43.5-45.5 GHz, and the Kaband, about 30-31 GHz.

Further, payload1400may also be configured to provide bypass1419for the Kaband. Bypass1419is a function which bypasses the return gateway downlink and the forward gateway uplink, thereby connecting the return uplink directly to the forward downlink. In some illustrative examples, payload1400may also include an in-band telemetry and command link.

Turning now toFIG. 15, yet another illustration of a payload is depicted in accordance with an illustrative embodiment. In this illustrative example, payload1500is an example of one implementation for payload208inFIG. 2. As depicted, payload1500is shown providing connectivity between terminal devices119and two gateways in gateways120inFIG. 1.

In these depicted examples, payload1500includes four dual-frequency single-polarization user pointed antennas1502. Each user pointed antenna in user pointed antennas1502receives return frequency hopped signals from terminal devices119within a coverage area of the antenna. User pointed antennas1502also transmits frequency hopped signals originating at the gateway back to terminal devices119within the coverage area of the antenna.

In this illustrative example, a single gateway-pointed antenna1524is also present. Gateway-pointed antenna1524forms one dual-frequency, dual-polarization, and directive gateway pointed coverage area.

In this example, the return frequency hopped signals are received by user pointed antennas1502and amplified by low noise amplifiers1506. Next, the frequency hopped signals are dehopped and down-converted using a dehopping local oscillator in the dehopping down-converters1508. The dehopped narrowband signals are then multiplexed together using an analog or digital channelizer1510. A fixed upconverter1512translates the frequency of the signals, as required, into the desired transmit band. As a result of the dehopping and multiplexing functions, the transmit band is reduced in bandwidth relative to the receive band. In this illustrative example, the dehopping and multiplexing can be achieved by analog means, digital means, or both. If the dehopping and multiplexing are implemented digitally, transmit power levels of individual channels can be controlled on a frequency hop by frequency hop basis. This entirely eliminates unpredictable power robbing in the satellite transmitter which may occur with an analog channelizer with finite response time, or bandwidth which is not perfectly matched to individual dehopped carriers.

As depicted, the frequency hopped signals are then amplified by linearized high-power amplifier1515and then transmitted to the gateway through the downlink port1514gateway-pointed antenna1524.

In this illustrative example, return frequency hopped signal sets from all antennas in user pointed antennas1502are multiplexed onto the same polarization of a common gateway pointed antenna feed. Multiplexed together with the signals to gateways120is a beacon signal from beacon1520. The beacon signal is used to aid in overall system syntonization and synchronization in these illustrative examples. The time and frequency reference subsystem1516provides includes the tunable master oscillator1522for the payload, the time-of-day and TRANSEC generator1518, as well as the beacon generator1520.

As depicted, the forward frequency hopped signals are received by gateway pointed antenna1524and amplified by low noise amplifiers1526. Next, the signals are de-multiplexed by de-multiplexer1528and down-converted by hopping local oscillators in the hopping down-converters1530. The signals are converted to the transmit band which is, by means of the frequency hopping, significantly wider in bandwidth than the receive band.

The frequency hopped signals are then amplified by high-power amplifier1532and then transmitted to the terminal devices119through downlink ports1534of user pointed antennas1502. In this illustrative example, frequency hopped signal sets destined for all four of user pointed antennas1502are multiplexed onto the same gateway pointed antenna feed using a common polarization. All frequencies are locked to tunable master oscillator1522, which is controlled by mission control system402inFIG. 4.

In some illustrative examples, payload1500may also include additional beacons to aid in terminal spatial acquisition of the satellite. Payload1500may also provide the flexibility to receive signals in one or more bands.

Further, payload1500may also be configured to support multiple receive bands, like payload1400, and to provide bypass function like payload1400. Bypass is a function which bypasses the return gateway downlink and the forward gateway uplink, thereby connecting the return uplink directly to the forward downlink.

Turning now toFIG. 16, an illustration of a message flow diagram for transmitting information in signals is depicted in accordance with an illustrative embodiment. In this depicted example, messages are exchanged between terminal device1600, satellite1602, gateway1604, and component1606. As depicted, terminal device1600may be in various locations. Terminal device1600may be associated with a platform such as an aircraft, a ground vehicle, a space station, a ship, a building, a person, or some other suitable type of platform.

Terminal device1600sends information in a wideband frequency hopping signal (message M1). Satellite1602receives the wideband frequency hopping signal and retransmits the wideband frequency hopping signal to gateway1604(message M2). The retransmission of the wideband frequency hopping signal is performed without any dehopping. In other words, the signal is not processed to identify the information in a channel having a number of frequencies in a range of frequencies for the signal.

The dehopping is performed by gateway1604when gateway1604receives the wideband frequency hopping signal from satellite1602. The wideband frequency hopping signal is processed to form a processed signal. The processed signal is transmitted to component1606(message M3). The processed signal may be another wideband frequency hopping signal if component1606is another satellite. If component1606is a terrestrial component such as a computer, a terminal device, a mission control center, or some other device on a terrestrial portion of the communications network, the processed signal may be sent as an internet protocol signal. The processed signal may be sent using at least one of a wired network, a wireless network, an optical network, a synchronous optical network, or some other suitable type of network.

Turning now toFIG. 17, an illustration of a flowchart of a process for configuring a communications network to send information is depicted in accordance with an illustrative embodiment. The process illustrated inFIG. 17may be implemented in communications network102inFIG. 1. In particular, one or more of the different operations may be implemented in a component such as ground system118inFIG. 1.

The process begins by identifying components for use in sending information (operation1700). These components may be, for example, a gateway, a satellite, a terminal device, or some other suitable type of component. The process identifies transmission security information for use in sending the information using the components (operation1702). The transmission security information identified may depend on the level of security desired for sending the information.

For example, if the information is sensitive or confidential, the transmission security information may include an identification of encryption algorithms, encryption keys, and other suitable information. If interference with the transmission of signals is undesired, then the transmission security information may also include a pseudorandom sequence that may be used for performing hopping and dehopping of the signals used to transfer the information.

The process then sends the transmission security information to the components (operation1704). This information may be distributed in a number of different ways. For example, the transmission security information may be sent by one or more gateways to the different components. This information may be transmitted as beacon information in a beacon signal. This information may be transmitted over a terrestrial network, over a satellite network, by courier, or by any other suitable means.

Next, the process synchronizes the components (operation1706), with the process terminating thereafter. This synchronization may be used to ensure that the different components involved in sending the information have substantially the same time. Time synchronization at the different components may be desired to ensure a particular level of security for information exchanged between the different components. For example, if hopping and dehopping of signals is performed, an incorrect frequency may be selected to hop or to dehop the carrier carrying the information if the time is not synchronized closely enough between the different components sending the information using frequency hopping signals. Furthermore if elements in the communications network are not well synchronized, carriers will interfere with each and cause degraded communications performance.

Turning now toFIG. 18, an illustration of a flowchart of a process for processing a signal is depicted in accordance with an illustrative embodiment. The process illustrated inFIG. 18may be implemented using communications network102inFIG. 1.

The process begins by modulating information on to a frequency hopping carrier (operation1800) to form a frequency hopping signal. The process then sends the frequency hopping signal to a gateway in a communications network through a satellite (operation1802). In operation1802, the frequency hopping signal is unprocessed by the satellite to identify the information in the frequency hopping signal.

The frequency hopping signal received at the gateway is processed to form a processed signal (operation1804). The processed signal is sent to another component (operation1806) with the process terminating thereafter. The component may be, for example, at least one of a terminal device, the satellite, another satellite, another gateway, and a control system. The processed signal may be another frequency hopping signal or may be a more conventional signal in which the information is sent using the same frequency and without changing the frequency during transmission of the signal.

Turning now toFIG. 19, an illustration of a flowchart of a process for processing a signal is depicted in accordance with an illustrative embodiment. The process illustrated inFIG. 19may be implemented in satellite200inFIG. 2.

As depicted, the process begins by receiving a signal in a receiver system in a satellite (operation1900). The signal has range of frequencies in which the information is carried in a channel having a different number of frequencies within the range of frequencies.

The process then transmits the signal to a remote location using a transmitter system in the satellite (operation1902) with the process terminating thereafter. The signals are unprocessed by the satellite to identify the channel used to carry the information in the signal. In other words, dehopping, rehopping, or both dehopping and rehopping are not performed by the satellite. Instead, this process of identifying the information carried in a signal may be performed by another device such as a gateway on a terrestrial portion of a communications network.

Turning now toFIG. 20, an illustration of a flowchart of a process for processing a signal is depicted in accordance with an illustrative embodiment. The process illustrated inFIG. 20may be implemented in gateways120inFIG. 1.

The process begins by receiving a signal from a satellite at a receiver system in a gateway (operation2000). The signal has a range of frequencies in which the information is carried in a channel having a number of frequencies within the range of frequencies. The number of frequencies is configured to change over time in the signal. The signal is processed using a signal processor in the gateway to identify a channel in which the number of frequencies within the range of frequencies is present (operation2002). The process identifies information carried in the channel (operation2004).

The information is used to generate a processed signal (operation2006). The process then transmits the processed signal to a destination device using a transmitter in the gateway (operation2008) with the process terminating thereafter.

The destination device may take various forms. The destination device may be selected from one of a satellite, a gateway, a terminal device, a control signal, or some other suitable destination device. The processed signal may take various forms depending on the destination device. For example, if the processed signal is a satellite, the processed signal may be a wideband frequency hopping signal.

If the destination device is a device connected to the gateway through a network on the terrestrial portion of the communications network, the signal may employ a protocol such as an internet protocol or some other suitable protocol without frequency hopping. The processed signal also may be encrypted in some illustrative examples.

The flowcharts and block diagrams in the different depicted embodiments illustrate the architecture, functionality, and operation of some possible implementations of apparatuses and methods in an illustrative embodiment. In this regard, each block in the flowcharts or block diagrams may represent a module, a segment, a function, and/or a portion of an operation or step. For example, one or more of the blocks may be implemented as program code, in hardware, or a combination of the program code and hardware. When implemented in hardware, the hardware may, for example, take the form of integrated circuits that are manufactured or configured to perform one or more operations in the flowcharts or block diagrams.

For example, operation1706inFIG. 17that performs synchronization may be optional. In another illustrative example, the synchronization in operation1706may be performed at the same time or prior to the transmission of transmission security information in operation1704.

Turning now toFIG. 21, an illustration of a block diagram of a data processing system is depicted in accordance with an illustrative embodiment. Data processing system2100may be used to implement computers used in implementing various devices in communications environment100inFIG. 1, number of computers246in satellite180inFIG. 2, and other suitable devices in the different illustrative examples. In this illustrative example, data processing system2100includes communications framework2102, which provides communications between processor unit2104, memory2106, persistent storage2108, communications unit2110, input/output unit2112, and display2114. In this example, communication framework may take the form of a bus system.

Processor unit2104serves to execute instructions for software that may be loaded into memory2106. Processor unit2104may be a number of processors, a multi-processor core, or some other type of processor, depending on the particular implementation.

Memory2106and persistent storage2108are examples of storage devices2116. A storage device is any piece of hardware that is capable of storing information, such as, for example, without limitation, data, program code in functional form, and/or other suitable information either on a temporary basis and/or a permanent basis. Storage devices2116may also be referred to as computer readable storage devices in these illustrative examples. Memory2106, in these examples, may be, for example, a random access memory or any other suitable volatile or non-volatile storage device. Persistent storage2108may take various forms, depending on the particular implementation.

For example, persistent storage2108may contain one or more components or devices. For example, persistent storage2108may be a hard drive, a flash memory, a rewritable optical disk, a rewritable magnetic tape, or some combination of the above. The media used by persistent storage2108also may be removable. For example, a removable hard drive may be used for persistent storage2108.

Communications unit2110, in these illustrative examples, provides for communications with other data processing systems or devices. In these illustrative examples, communications unit2110is a network interface card.

Input/output unit2112allows for input and output of data with other devices that may be connected to data processing system2100. For example, input/output unit2112may provide a connection for user input through a keyboard, a mouse, and/or some other suitable input device. Further, input/output unit2112may send output to a printer. Display2114provides a mechanism to display information to a user.

Instructions for the operating system, applications, and/or programs may be located in storage devices2116, which are in communication with processor unit2104through communications framework2102. The processes of the different embodiments may be performed by processor unit2104using computer-implemented instructions, which may be located in a memory, such as memory2106.

These instructions are referred to as program code, computer usable program code, or computer readable program code that may be read and executed by a processor in processor unit2104. The program code in the different embodiments may be embodied on different physical or computer readable storage media, such as memory2106or persistent storage2108.

Program code2118is located in a functional form on computer readable media2120that is selectively removable and may be loaded onto or transferred to data processing system2100for execution by processor unit2104. Program code2118and computer readable media2120form computer program product2122in these illustrative examples. In one example, computer readable media2120may be computer readable storage media2124or computer readable signal media2126.

In these illustrative examples, computer readable storage media2124is a physical or tangible storage device used to store program code2118rather than a medium that propagates or transmits program code2118.

Alternatively, program code2118may be transferred to data processing system2100using computer readable signal media2126. Computer readable signal media2126may be, for example, a propagated data signal containing program code2118. For example, computer readable signal media2126may be an electromagnetic signal, an optical signal, and/or any other suitable type of signal. These signals may be transmitted over communications links, such as wireless communications links, optical fiber cable, coaxial cable, a wire, and/or any other suitable type of communications link.

The different components illustrated for data processing system2100are not meant to provide architectural limitations to the manner in which different embodiments may be implemented. The different illustrative embodiments may be implemented in a data processing system including components in addition to and/or in place of those illustrated for data processing system2100. Other components shown inFIG. 21can be varied from the illustrative examples shown. The different embodiments may be implemented using any hardware device or system capable of running program code2118.

With the use of an illustrative embodiment, the cost, complexity, and size of satellites used for communications between orbital and non-orbital devices may be reduced. Further, since non-orbital gateway devices perform full signal processing, communications performance is better than with space-based partial-processed systems that demodulate only with hard decisions and do not soft-decision decode or de-interleave.

In addition, upgrades or modifications to the satellite communication system are relatively simple and inexpensive and do not entail orbital or space-based changes such as launching new satellites. Moreover, if the gateway device is remotely located, effects of uplink jamming in a particular user beam are not readily detectable by the jammer in that beam, thus denying the jammer feedback as to the effectiveness of its jamming techniques.

In a particular embodiment, no narrowband filtering is performed by the satellite-based communications system. In this embodiment, a return link downlink transmitter is adapted to be very robust to jammers. To provide a large gateway spectrum, many gateways and polarizations may be used. Additionally, adaptive power balance of dual polarization may be used on return downlinks so that jammers do not cause adverse affects on signals in non-jammed uplink beams.

Disclosed embodiments enable multiple extended data rate (XDR) circuits to use terrestrial connectivity to a relatively small number of Earth stations located on the Earth or moving with the atmosphere of the earth.

Additionally, these embodiments may be compatible with open standard for synchronization of orthogonal frequency-hopped signals using different air interface waveforms at all communication stack layers. Further, full processing XDR waveforms at the gateway devices enables improved performance relative to conventional communication systems in both additive white Gaussian noise (AWGN) and jamming environments, while maintaining backward compatibility with XDR waveform standards.

Consolidation of resource control for a multiplicity of payloads at a multiplicity of orbital slots and a multiplicity of gateways reduces coordination of distributed resource management databases (e.g., distinct resource control databases for each satellite or gateway) and simplifies resource control protocols and messaging for such activities as log-on/log-off; establishing, modifying, and releasing services; service reconfiguration; beam management; and resource monitoring. Consolidated resource control for all system transponders on all satellites and for all gateway devices and terrestrial resources eliminates mediation problems and crosslink protocols required in more traditional systems to maintain database synchronization.

Disclosed embodiments provide return link robustness to in-beam interference and reduce power-robbing on return link downlink transmitters. Additionally, return link downlink transmitters that are used are linear and robust enough to handle instantaneous power pulses with peak power significantly higher than average jammer power.

In a particular embodiment, multiple gateways use multiple polarizations to support a multiplicity of uplink user beams. Linear return downlinks are used to mitigate negative communications performance impact due to intermodulation products, signal suppression, and power robbing due to the received jammer signal, with average power many times larger than signals of interest and with instantaneous jammer power pulses with peak power significantly higher than average jammer power. Power-balanced return downlinks are used in order to mitigate negative communications performance impact on non-jammed beams in the presence of jamming on other beams. Additionally, synchronization of multiple gateways may be used so that orthogonal frequency-hopped signals synchronized to different gateways do not interfere with each other. For example, gateways may be independently synchronized to coordinated universal time (UTC) using local global positioning system (GPS) enabled devices.

Additionally, differences in propagation delay to the multiple gateways may be partially calibrated using ranging and ephemeris determination techniques. Residual calibration may be conducted by broadcasting a common beacon from a satellite to the multiple gateways. This one-way beacon provides a jam-resistant signal for use in calibration since turn-around ranging would be more vulnerable to jamming. The beacon may be multiplexed on the same transmitter as the return downlink.

Additionally, a common payload generated beacon may be used for gateway synchronization, system synchronization, system syntonization, and gateway and terminal antenna auto-tracking. A code may be used to resolve residual differential range ambiguity after using ephemeris estimation techniques. For example, a pseudorandom noise (PRN) code or a balanced PRN code can be used. A mission control system may monitor beacon transmissions to determine and correct satellite time and frequency drift relative to a master gateway and to determine and correct slave gateway time and frequency drift relative to a master gateway.

In a particular embodiment, processing that is performed in orbit on the satellite-based transponder may be limited to low-noise amplification, frequency conversion, gain/level control, linearization, high power and high gain amplification. In other embodiments, processing performed at the satellite-based transponder may also include dehopping and rehopping of signals based on time-of-day transmission security. In embodiments where dehopping and rehopping of signals is performed in space, a time stamped time-of-day-based beacon may be used to aid the gateway and mission control functions to advance uplink and retard downlink time-of-day to account for gateway propagation delay. In other embodiments, processing performed at the satellite-based transponder may also include digital channelization after dehopping of signals. Digital channelization enables hop-by-hop level control of each individual channel, eliminating power robbing effects in the downlink transmitter.

Accordingly, disclosed embodiments reduce development, deployment, and production costs of anti-jam satellite communications and provide improved anti-jam communications performance. Further, ground-based processing used in the embodiments disclosed facilitates rapid and cost-effective system upgrades that can be effectively synchronized with terminal upgrades.

Thus, future anti-jam waveforms may be supported readily which may include enhanced waveform features such as bandwidth-on-demand, adaptive coding and modulation, bandwidth efficient modulation, beam handover, label switching, packet-switching, Suite B crypto, resilience to blockage environment, increased data rates, or some combination thereof. Further, the disclosed embodiments support protected communication-on-the-move (COTM) and provide efficient support for interconnectivity to terrestrial users and services without using precious EHF spectrum. Moreover, the disclosed embodiments can be used to provide jammer standoff comparable to current state of the art systems but with higher data rates and with significantly higher antenna gain.

Thus, the illustrative embodiments provide a method and apparatus for communicating information. Different illustrative embodiments may provide different features from other illustrative embodiments. Further, features in the different examples described and depicted in the figures may be combined with features in other examples.

In one illustrative example, a gateway comprises a receiver, a signal processor, and a transmitter. The receiver is configured to receive a wideband frequency hopping signal from an originating terminal via a satellite transponder. The satellite transponder does not dehop the wideband frequency hopping signal. The signal processor is configured to dehop the wideband frequency hopping signal to form a processed signal. The transmitter is configured to transmit content of the processed signal to a destination terminal device.

The transmitter in the gateway may be configured to wideband frequency hop the processed signal to form a second forward wideband frequency hopping signal and transmit the second forward wideband frequency hopping signal to a second satellite transponder for relay to the destination terminal device.

The second forward signal formed by the transmitter in the gateway may not be wideband frequency hopped. Further, the transmitter in the gateway may be configured to transmit the processed signal to the destination terminal via a ground-based wired and/or wireless network. The transmitter in the gateway also may be configured to transmit the processed signal to the destination terminal via a synchronous optical network (SONET). Further, the transmitter in the gateway may be configured to transmit the processed signal to the destination terminal using internet protocol and/or other digital communications.

In another illustrative example, a gateway comprises a receiver and a signal processor. The receiver is configured to receive a beacon signal from a satellite-based transmitter. The signal processor is configured to use the beacon signal to synchronize, at the satellite, forward and return gateway signals with forward and return gateway signals from one or more additional gateways.

The beacon signal may be multiplexed with a return downlink signal received from the satellite-based transmitter. The beacon signal may comprise a pseudorandom noise code. The beacon signal also may comprise a ranging sequence. Further, a return downlink of the satellite-based transmitter may include two or more signals with different polarization.

The return downlink signal may be a wideband frequency hopping signal. The signal processor may be configured to dehop the wideband frequency hopping signal to form a processed signal. Also, the gateway may perform time-sensitive time synchronization acquisition and tracking processing.

The gateway may further comprise a transmitter to transmit content of the processed signal to a destination terminal. The signal processor may use the beacon signal to synchronize the gateway.

The gateway may include an antenna auto-tracking system coupled to the signal processor, wherein the antenna auto-tracking system uses the beacon signal to track the satellite-based transmitter.

In yet another illustrative example, a communication system comprises an antenna and a first gateway. The first gateway is coupled to the antenna and is configured to communicate with one or more terminal devices via a first transponder using wideband frequency hopping signals first transponder does not dehop the wideband frequency hopping signals.

The communication system also may include a second gateway device coupled to the antenna or to another antenna. The second gateway device may be co-located with the first gateway or located in a location that is geographically remote from the first gateway. The second gateway device may be further configured to communicate with the one or more terminal devices via a second transponder using wideband frequency hopping signals. The second transponder does not dehop the wideband frequency hopping signals and the second gateway device communicates with the one or more terminal devices via the second transponder concurrently with the first gateway device communicating with the one or more terminal devices via the first transponder.

The communication system also may comprise a mission control system coupled to the first gateway devices. The communication system also may comprise a payload control system coupled to the mission control system and configured to control signals to the first transponder via the mission control system and the first gateway. The control signals may include gain or level control or antenna pointing commands used to control return downlink transmitter gain or level settings or to control a pointing direction of an antenna of the first transponder.

The communication system may further comprise a resource control and mission planning system coupled to the mission control system and configured to control reservation of satellite and gateway communication resources and activation of the satellite and gateway communication resources. The resource control and mission planning system communicates with at least one of the first gateway and a second gateway.

The first transponder may be a component of a first satellite and the communications system may include at least one second transponder that is a component of a second satellite. The first satellite and the second satellite do not communicate directly with one another via a satellite crosslink to coordinate resource control and mission planning.

The communication system may further comprise a unified resource control and mission planning database coupled to the resource control and mission planning system. The unified resource control and mission planning database stores resource control and mission planning information related to a plurality of satellite transponder systems that facilitate communications between the one or more terminal devices.

The communication system may include a common resources control database that is used to manage system transponders including the first transponder and the at least one second transponder. The communication system may also include a common resource management database that is used for mission planning and resource control. A resource control system activates resources that are identified, allocated, and reserved in the common resource management database by a mission planning system.

The communication system may further comprise a central key facility that is coupled to the mission control system and configured to send frequency hop code information, transmission security keys, and access control keys to the one or more terminal devices. The frequency hop code information is used by the one or more terminal devices to determine a frequency hop pattern of the wideband frequency hopping signals.

The first gateway may be further configured to communicate with the one or more terminal devices via a second transponder using the wideband frequency hopping signals. The second transponder does not dehop the wideband frequency hopping signals. The first gateway device may include a terrestrial network interface adapted to be coupled to a terrestrial network.

The first gateway may be configured to receive data in a digital format via the terrestrial network and to send the data to a particular terminal device of the one or more terminal devices via the first transponder. The first gateway may be configured to receive data from a particular terminal device of the one or more terminal devices via the first transponder using the wideband frequency hopping signals and to send the data to a device coupled to the terrestrial network using a digital format via the terrestrial network. The terrestrial network may be a synchronous optical network.

The first gateway device may be configured to be switchable, independently for each feeder link polarization, between two frequency band or frequency polarization modes, including a Ka-band mode and an extremely high frequency (EHF)-band mode. When a first gateway feeder link polarization is a first frequency band or polarization mode, a user interface is comprised of signals in the first frequency band or polarization mode that are either non-hopped or wideband frequency hopped. When the first gateway feeder link polarization is a second frequency band or polarization mode, the user interface is comprised of signals in the second frequency band or polarization mode that are wideband frequency hopping signals.

The wideband frequency hopping signals may include first signals having a first polarization and second signals having a second polarization, the first polarization orthogonal to the second polarization. The first signals may have the first polarization and the second signals may have the second polarization. These signals are power balanced. The first signals having the first polarization and the second signals having the second polarization may use orthogonal frequency channels that are synchronously frequency hopped.

The wideband frequency hopping signals may be multiplexed with a beacon signal by the first transponder. The first gateway device uses the beacon signal to synchronize the first gateway device with at least one second gateway device. The first gateway may further use the beacon signal for synchronization. The first gateway device may provide information derived from the beacon signal to an auto-tracking system of the antenna.

In still another illustrative example, a command system comprises a processor and a memory. The memory is accessible to the processor. The memory stores instructions executable by the processor to cause the processor to send control signals to a plurality of satellite platforms via one or more terrestrial gateway devices. The control signals include resource control signals and mission planning signals.

The control signals may further include a payload control signal sent to at least one of a satellite platform and/or payload of the plurality of satellite platforms via the one or more terrestrial gateway devices. The payload control signal may be an antenna pointing signal. The instructions may be further executable by the processor to cause the processor to send transmission security (TRANSEC) information to one or more gateways of one or more terrestrial gateway devices.

The command system may further comprise a terrestrial network interface. The control signals are sent to the one or more terrestrial gateway devices via the terrestrial network interface using digital communications via a wired or wireless terrestrial network. The instructions may be further executable by the processor to cause the processor to maintain a unified resource control and mission planning database.

In another illustrative example, a satellite comprises a receiver and a transmitter. The receiver is configured to receive a wideband frequency hopping signal from a non-orbital transmitter. The transmitter is configured to retransmit the wideband frequency hopping signal to a non-orbital receiver without dehopping the wideband frequency hopping signal.

The retransmission by the transmitter may not be wideband frequency hopped. The wideband frequency hopping signal may not be filtered with narrowband filters before the transmitter retransmits the wideband frequency hopping signal.

The satellite may further comprises a linear transmitter for a return gateway link to mitigate negative communications performance impact due to intermodulation products, signal suppression, and power robbing due to received jammer signals, with average power higher than signals of interest and with instantaneous jammer power pulses with peak power higher than average jammer power. The satellite may further comprise narrow uplink beams to provide antenna isolation from unwanted jammer signals that may be present in a forward uplink band. The satellite may further comprise narrow beams to provide antenna isolation from unwanted jammer signals that may be present in a return uplink band.

The satellite may further comprise a beacon generator coupled to the transmitter. The beacon generator generates a beacon signal that is multiplexed with the wideband frequency hopping signal for transmission by the transmitter. The satellite may further comprise at least one second transmitter to transmit a second wideband frequency hopping signal to the non-orbital receiver or to a second non-orbital receiver concurrently with the transmitter retransmitting the wideband frequency hopping signal to the non-orbital receiver.

The transmitter may transmit the wideband frequency hopping signal using a first polarization. The at least one second transmitter transmits the second wideband frequency hopping signal using a second polarization that is orthogonal to the first polarization. The wideband frequency hopping signal and the second wideband frequency hopping signal may be power balanced. The signals may have a first polarization and a second polarization and may use orthogonal frequency channels that are synchronously frequency hopped.

In still another illustrative example, a terminal device comprises a transmitter. The transmitter is configured to send a wideband frequency hopping signal to a destination device via a satellite transponder. The satellite transponder does not dehop the wideband frequency hopping signal before retransmitting the wideband frequency hopping signal to a non-orbital receiver.

In yet another illustrative example, a terminal device comprises a terrestrial network interface that is adapted to send data to a destination device by transmitting an internet protocol or other digital signal to a satellite uplink station that communicates with the destination device by sending a wideband frequency hopping signal to a satellite transponder. The satellite transponder does not dehop the wideband frequency hopping signal before retransmitting the wideband frequency hopping signal to a non-orbital receiver.

In another illustrative example, a method comprises sending a first wideband frequency hopping signal from a first terminal device to a satellite; receiving the wideband frequency hopping signal at the satellite and relaying the wideband frequency hopping signal to a ground station without dehopping the wideband frequency hopping signal; processing the wideband frequency hopping signal at the ground station, wherein processing the wideband frequency hopping signal includes dehopping the wideband frequency hopping signal; sending a second forward wideband frequency hopping signal including content of the wideband frequency hopping signal from the ground station to the satellite or to a second satellite, or from the ground station to the satellite or to the second satellite via a second ground station; and receiving the second forward wideband frequency hopping signal at the satellite or the second satellite and relaying the wideband frequency hopping signal to a second terminal device without dehopping the second wideband frequency hopping signal. A second forward signal is not wideband frequency hopped.

The ground station in the method may include multiple gateways. Each of the multiple gateways is configured to process multiple communication links concurrently. The wideband frequency hopping signal in the method may be an extended data rate (XDR) waveform, or an alternate waveform or combination of waveforms that includes enhanced waveform features including one or more of bandwidth-on-demand, adaptive coding and modulation, bandwidth efficient modulation, beam handover, label and/or packet-switching, Suite B crypto, and resilience to blockage environment. The extended data rate waveform may be fully processed, including forward error correction encoding and decoding and channel interleaving and de-interleaving, at a gateway. The method may further comprise multiplexing a beacon signal with the first wideband frequency hopping signal when the first wideband frequency hopping signal is relayed from the satellite to the ground station.

In still another illustrative example, a method comprises receiving, at a gateway device, data from a ground terminal via wired or unwired connection using an internet protocol or other digital communication and transmitting the data in a wideband frequency hopping signal to a destination device via a satellite transponder. The satellite transponder does not dehop the wideband frequency hopping signal before retransmitting the wideband frequency hopping signal to the destination device.

In still yet another illustrative example, a method comprises receiving, at a gateway device, data from a satellite transponder via a wideband frequency hopping signal; dehopping the wideband frequency hopping signal at the gateway device; and transmitting the data in a second signal to a destination device via wired or unwired connection using an internet protocol or other digital communication.

In an illustrative example, a method for processing a signal is present. The method may include encoding information in a frequency hopping signal; and sending the frequency hopping signal to a gateway in a communications network through a satellite, wherein the frequency hopping signal is unprocessed by the satellite to identify the information in the frequency hopping signal.

The method may further include processing the frequency hopping signal to form a processed signal. Additionally the method may also include sending the processed signal to at least one of a terminal device, the satellite, another satellite, another gateway, and a control system. Further the method may include receiving the signal in a receiver system in a satellite, wherein the signal has a range of frequencies in which information is carried in a number of channels having a number of frequencies within the range of frequencies, wherein the number of frequencies for a channel in the number of channels changes within the range of frequencies over time; and transmitting the signal using a transmitter system in the satellite, wherein the signal is processed to identify the number of frequencies for a channel in the number of channels used to carry the information by the satellite, and wherein the signal is digitally processed so that its gain and power level can be controlled on a dynamic hop-by-hop basis in order to control power robbing in the transponder. The signal may be further digitally processed so that its channelization bandwidth can be controlled on a dynamic hop-by-hop basis in order to control power robbing in the transponder.

In another illustrative example, an apparatus comprises a receiver system and a transmitter system. The receiver system in a satellite is configured to receive a signal having a range of frequencies in which information is carried in a number of channels having a number of frequencies within the range of frequencies, wherein the number of frequencies for the channel changes within the range of frequencies over time. The transmitter system in the satellite is configured to transmit the signal, wherein the signal is processed to identify the number of frequencies for a channel in the number of channels used to carry the information by the satellite, and wherein the signal is digitally processed so that its gain and power level can be controlled on a dynamic hop-by-hop basis in order to control power robbing in the transponder. The signal may be further digitally processed so that its channelization bandwidth can be controlled on a dynamic hop-by-hop basis in order to control power robbing in the transponder.

The apparatus also may include a beacon generator in the satellite, wherein the beacon generator is configured to generate beacon information and the transmitter system is configured to include the beacon information in the signal. The beacon information may include a timestamp and at least one of a pseudo random sequence, a ranging sequence, and a pseudorandom noise code.

In another illustrative example, a method of processing a signal is present and includes receiving the signal in a receiver system in a satellite, wherein the signal has a range of frequencies in which information is carried in a number of channels having a number of frequencies within the range of frequencies, wherein the number of frequencies for a channel in the number of channels changes within the range of frequencies over time; and transmitting the signal using a transmitter system in the satellite, wherein the signal is processed to identify the number of frequencies for a channel in the number of channels used to carry the information by the satellite, and wherein the signal is digitally processed so that its gain and power level can be controlled on a dynamic hop-by-hop basis in order to control power robbing in the transponder. The signal may be further digitally processed so that its channelization bandwidth can be controlled on a dynamic hop-by-hop basis in order to control power robbing in the transponder.

In the illustrative examples, the method may include a scheme to synchronize the payload and the gateway with a beacon generator, wherein the beacon information includes a timestamp and at least one of a pseudo random sequence, a ranging sequence, and a pseudorandom noise code.

In another illustrative example, A communication system may also include a receiver system in a satellite configured to receive a signal having a range of frequencies in which information is carried in a number of channels having a number of frequencies within the range of frequencies, wherein the number of frequencies for the channel changes within the range of frequencies over time; and a transmitter system in the satellite configured to transmit the signal, wherein the signal is processed to identify the number of frequencies for a channel in the number of channels used to carry the information by the satellite, and wherein the signal is digitally processed so that its gain and power level can be controlled on a dynamic hop-by-hop basis in order to control power robbing in the transponder. The signal may be further digitally processed so that its channelization bandwidth can be controlled on a dynamic hop-by-hop basis in order to control power robbing in the transponder. The communications system may also include a beacon generator in the satellite, wherein the beacon generator is configured to generate beacon information and the transmitter system is configured to include the beacon information in the signal. The beacon information includes a timestamp and at least one of a pseudo random sequence, a ranging sequence, and a pseudorandom noise code.

In still another illustrative example, An apparatus comprises a receiver system in a gateway configured to receive a signal from a satellite, wherein the signal has a range of frequencies in which information is carried in a number of channels having a number of frequencies within the range of frequencies, wherein the number of frequencies for the channel changes within the range of frequencies over time and wherein the signal is unprocessed by the satellite to identify the number of frequencies for a channel in the number of channels used to carry the information by the satellite; and a communications processor in the gateway configured to process the signal to identify the channel in the number of frequencies within the range of the frequencies to form a processed signal and transmit the processed signal to a destination device. The apparatus also may comprise a receiver system in a satellite configured to receive a signal having a range of frequencies in which information is carried in a number of channels having a number of frequencies within the range of frequencies, wherein the number of frequencies for the channel changes within the range of frequencies over time; and a transmitter system in the satellite configured to transmit the signal, wherein the signal is processed to identify the number of frequencies for a channel in the number of channels used to carry the information by the satellite, and wherein the signal is digitally processed so that its gain and power level can be controlled on a dynamic hop-by-hop basis in order to control power robbing in the transponder. The signal is further digitally processed so that its channelization bandwidth can be controlled on a dynamic hop-by-hop basis in order to control power robbing in the transponder. The apparatus also may include a beacon generator in the satellite, wherein the beacon generator is configured to generate beacon information and the transmitter system is configured to include the beacon information in the signal. The beacon information includes a timestamp and at least one of a pseudo random sequence, a ranging sequence, and a pseudorandom noise code.

The description of the different illustrative embodiments has been presented for purposes of illustration and description, and is not intended to be exhaustive or limited to the embodiments in the form disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art. As another example, one or more illustrative embodiments may also be used with spacecraft traveling in space but not in orbit around the Earth. These spacecraft may also relay signals without hopping or dehopping. Further, different illustrative embodiments may provide different features as compared to other illustrative embodiments. The embodiment or embodiments selected are chosen and described in order to best explain the principles of the embodiments, the practical application, and to enable others of ordinary skill in the art to understand the disclosure for various embodiments with various modifications as are suited to the particular use contemplated.