Patent ID: 12204019

DETAILED DESCRIPTION

Various examples of systems, devices, and/or methods are described herein. Any embodiment, implementation, and/or feature described herein as being an example is not necessarily to be construed as preferred or advantageous over any other embodiment, implementation, and/or feature unless stated as such. Thus, other embodiments, implementations, and/or features may be utilized, and other changes may be made without departing from the scope of the subject matter presented herein.

Accordingly, the examples described herein are not meant to be limiting. It will be readily understood that the aspects of the present disclosure, as generally described herein, and illustrated in the figures, can be arranged, substituted, combined, separated, and designed in a wide variety of different configurations.

Further, unless the context suggests otherwise, the features illustrated in each of the figures may be used in combination with one another. Thus, the figures should be generally viewed as component aspects of one or more overall embodiments, with the understanding that not all illustrated features are necessary for each embodiment.

Additionally, any enumeration of elements, blocks, or steps in this specification or the claims is for purposes of clarity. Thus, such enumeration should not be interpreted to require or imply that these elements, blocks, or steps adhere to a particular arrangement or are carried out in a particular order.

Moreover, terms such as “substantially” or “about” that may be used herein are meant that the recited characteristic, parameter, or value need not be achieved exactly, but that deviations or variations, including, for example, tolerances, measurement error, measurement accuracy limitations and other factors known to those skilled in the art, may occur in amounts that do not preclude the effect the characteristic was intended to provide.

As noted above, some electric vertical take-off and landing (eVTOL) aircraft are equipped with a GNSS receiver that facilitates navigation. However, such a navigation system does not provide the level of integrity, precision, and availability that is anticipated to be required by various regulatory agencies that regulate these activities. In particular, such navigation systems will not support, for example, vertical take-off/landing in dense urban areas where room for a landing area is limited. Landing in such areas is expected to require a horizontal and vertical position accuracy of 0.5 meters and 0.1 meters, respectively, with an expected failure probability of less than 10−9.

These and other issues are ameliorated by various navigation, take-off, and landing support system (NTLS) examples described herein. Some examples of the NTLS comprise several pseudolites (short for pseudo satellite) distributed proximate a landing area such as a landing area in a densely populated area. In an example, at least four pseudolites are provided to facilitate the triangulation of the aerial vehicle. Each pseudolite is configured to transmit a radio frequency (RF) signal that facilitates determining, by the aerial vehicle, a distance between the pseudolite and the aerial vehicle. Some examples of the NTLS include a monitoring receiver positioned proximate the landing area, and that is configured to receive the RF signals from the pseudolites. Some examples of the NTLS include a control system that is in communication with the pseudolites and the monitoring receiver. The control system is configured to determine, based on the RF signals received from the monitoring receiver, whether the pseudolites are operating within a nominal operating range.

Some examples of the NTLS include a number of pseudolites that is greater than the minimum number of pseudolites (e.g., four) needed to perform trilateration. For instance, an example of the NTLS includes ten pseudolites. The extra pseudolites facilitate improved location accuracy. Further, in the event that a particular pseudolite fails or otherwise begins to operate outside of a nominal operating range, it can be taken offline, and the number of remaining pseudolites is still sufficient to facilitate the performance of trilateration. In some examples, pseudolites that are operating outside of a nominal operating range are taken offline or instructed to broadcast an indication of the same (e.g., via the RF signals).

Some examples of the NTLS include additional and/or redundant monitoring receivers. In some examples, when the RF signals received by a majority of the monitoring receivers indicate that a particular pseudolite is in a particular state of operation (e.g., inoperative), the control system is configured to determine the particular pseudolite is in that particular state of operation. In some examples, when a particular monitoring receiver indicates a state of pseudolite operation that is different from the state of pseudolite operation indicated by the majority of monitoring receivers, the system is configured to determine that the monitoring receiver is operating outside of a nominal operating range.

Some examples of the NTLS include a primary control system, a redundant control system, a primary network, a redundant network, a primary power system, and a redundant power system. The primary and redundant networks facilitate communications between the control systems, pseudolites, and monitoring receivers. The primary and redundant power systems are configured to supply power to the networks, control systems, pseudolites, and monitoring receivers. In some examples, the primary control system and the redundant control system are configured to determine whether the primary network and/or the primary power system are inoperable and to utilize the redundant network for communications when the primary network is inoperable and to use the redundant power system to supply power when the primary power system is inoperable. In some examples, the redundant control system is configured to determine whether the primary control system is inoperable and to control operations of the NTLS when the primary control system is inoperable.

Some examples of the NTLS include a bi-directional RF communication system that is in communication with the control system. In some examples, the control system is configured to receive, via the bi-directional RF communication system, a landing request from the aerial vehicle. The control system then determines whether the aerial vehicle is authorized to land at the landing area and, if so, communicates an encryption key to the aerial vehicle that facilitates decoding, by the aerial vehicle, information in the RF signals.

Some examples of the control system are configured to communicate landing area information associated with the landing area to the aerial vehicle via the bi-directional RF communication system. Some examples of the control system communicate one or more waypoints to the aerial vehicle that facilitates navigating the aerial vehicle from a current location to the landing area. Some examples of the waypoints specify a location and a time at which the aerial vehicle150should arrive at the location specified by the waypoint.

Some examples of the landing area information indicate particular pseudolites of the NTLS that are operating within a nominal operating range. This, in turn, allows the aerial vehicle to base its location on RF signals received from the nominally operating pseudolites and to reject RF signals from those pseudolites that are operating outside of a nominal operating range. As noted above, some examples of pseudolites communicate their respective operational status in the RF signal and in some examples, the aerial vehicle determines the operational state of the pseudolites based on this information in the RF signal.

FIG.1Aillustrates an example of a navigation, take-off, and landing support system (NTLS)100that facilitates vertical landing at a landing area105by an aerial vehicle150. The NTLS100includes a plurality of pseudolites110, one or more monitoring receivers115, and one or more control systems102. Some examples of the NTLS100include a bi-directional RF communication system117, one or more networks108, and one or more power systems104.

Some examples of the power systems104are configured to supply power to the various subsystems of the NTLS100. Some examples of the power systems104receive power from a power utility and are configured to generate power in the case of utility power loss. In this regard, some examples of the power systems104comprise batteries or gas generators from which power is derived in the case of utility power loss. Some examples of the power systems104operate as redundant power systems104and are configured to supply power to the various subsystems of the NTLS100when one or more primary power systems104fail.

Some examples of the networks108facilitate communications between the various subsystems of the NTLS100. Some examples of the networks108correspond to wireless, wired and/or fiber networks. Some examples of the networks108operate as redundant networks108and are configured to facilitate communications between the various subsystems of the NTLS100when one or more primary networks108fail.

Some examples of the pseudolites110are distributed proximate the landing area105. For instance, some examples of the pseudolites110are distributed along the perimeter of the landing area105. In this regard, some examples of the landing area105comprise one or more landing area regions that accommodate the simultaneous landing of a corresponding number of aerial vehicles150.

Some examples of the pseudolites110are configured to transmit a radio frequency (RF) signal125that facilitates determining, by the aerial vehicle150, a distance between the pseudolite110and the aerial vehicle150. Some examples of the RF signal125comprise information that facilitates determining by the aerial vehicle150whether the pseudolite110is operating within a nominal operating range. Some examples of the aerial vehicles150utilize information from several pseudolites110(e.g., four or more) to precisely locate the landing area105or a particular landing area region within the landing area105. In this regard, some examples of the aerial vehicle150perform trilateration based on the RF signals125to locate the landing area105.

Some examples of the RF signal125comprise location data that specifies a location of a corresponding pseudolite110. Some examples of the location data correspond to geospatial coordinates of the pseudolite110. In this regard, in some examples, the location of each pseudolite110is precisely determined by surveying equipment and, in some cases, is accurate to within several centimeters.

Some examples of the RF signal125comprise integrity data that specifies whether the pseudolite110is operating within a nominal operating range. For instance, some examples of the RF signal125indicate whether the pseudolite110should be used for location determination, whether the pseudolite110is scheduled for maintenance, etc.

Some examples of the RF signal125comprise a pseudorandom code that facilitates deriving, by the aerial vehicle150, a code-phase and a carrier-phase that facilitate measuring a distance between the aerial vehicle150and the particular pseudolite110. In an example, the code-phase facilitates determining the location of the landing area105(or landing area region within the landing area105) to within several meters of accuracy, and the carrier-phase facilitates refining this measurement to within centimeters of accuracy.

In some examples, the pseudorandom code associated with a group of pseudolites110distributed proximate a particular landing area105(e.g., a particular city or location in the city) is the same. In some examples, the pseudorandom code associated with a different group of pseudolites110distributed proximate a different landing area105(e.g., in a different city or different location of the city) is different from the pseudorandom code associated with the first group of pseudolites110. In some examples, the RF signal125comprises a carrier wave that is in the gigahertz range (e.g., 1 GHZ, 2 GHZ, etc.)

Referring toFIG.1B, some examples of pseudolites110include a pseudorandom code generator155configured to generate the pseudorandom code specified in the RF signal. Some examples of the pseudorandom code generator155derive timing information from a common clock source151so that pseudorandom codes generated by each pseudolite110have the same phase and frequency. In this regard, in some examples, the common clock is communicated (e.g., via the network108) to each pseudolite110from a particular monitoring receiver115, a particular pseudolite110(e.g., master pseudolites), the control system102, etc.

Some examples of the pseudorandom code generator155derive timing information from clock sources that are asynchronous. In this regard, some examples of the pseudolites110comprise a precision clock source (e.g., an atomic clock) that generates a clock signal. In some examples, the frequency and phase of the clock signal are calibrated from time to time (e.g., by the control system102and based on information received from the RF monitoring station115) to minimize differences between respective frequencies and phases of the clock signals. Additionally, or alternatively, in some examples, timing information (e.g., relative differences in frequencies and phases) associated with the pseudorandom code of each pseudolite110is communicated to the aerial vehicle150to facilitate performing trilateration based on RF signals received from the pseudolites110that take into account this timing information.

Some examples of the monitoring receivers115are positioned proximate the landing area105and are configured to receive the RF signals125from the pseudolites110. The monitoring receivers115are configured to receive the RF signals125from the pseudolites110to facilitate determining whether the pseudolites110are operating within a nominal operating range. For instance, in some examples, aspects of the RF signal125(e.g., carrier frequency, phase, pseudorandom code, etc.) are compared with expected values. In some examples, when values associated with these aspects for a particular pseudolite110deviate by a predetermined amount, the pseudolite110is determined to be operating outside of a nominal operating range. In this regard, some examples of the monitoring receivers115are configured to measure the code phase and the carrier phase associated with each of the plurality of pseudolites and determine, based on the code phase and the carrier phase of the RF signal, corresponding clock bias estimates associated with the RF signals of each pseudolite110.

Some examples of the bi-directional RF communication system117implement a bi-directional communication channel130that facilitates transmitting information to the aerial vehicle150, such as landing area105information associated with the state of equipment at the landing area105(e.g., the operational status of pseudolites110at the landing area105). Some examples of the bi-directional RF communication system117are configured to facilitate processing a landing request communicated from an aerial vehicle150via the bi-directional communication channel130.

FIG.2illustrates an example of a control system102. The control system102includes a processor225, a memory227in communication with the processor225, and an input/output (I/O) subsystem210.

The processor225is in communication with the memory227. The processor225is configured to execute instruction code stored in the memory227. The instruction code facilitates performing, by the control system102, various operations that are described herein. In this regard, the instruction code may cause the processor225to control and coordinate various activities performed by the different subsystems of the control system102and/or the NTLS100. Some examples of the processor225can correspond to a stand-alone computer system such as an ARM®, Intel®, AMD®, or PowerPC® based computer system or a different computer system and can include application-specific computer systems. The computer system can include an operating system, such as Windows®, Linux®, Unix®, or a different operating system.

Some examples of the I/O subsystem210include one or more input/output interfaces configured to facilitate communications with subsystems of the NTLS100. An example of the I/O subsystem210includes wired or wireless communication circuitry configured to facilitate communicating information. An example of the wireless communication circuitry includes cellular telephone communication circuitry configured to communicate information over a cellular telephone network such as a 3G, 4G, and/or 5G network. Other examples of the wireless communication circuitry facilitate communication of information via an 802.11 based network, Bluetooth®, Zigbee®, near field communication technology or a different wireless network.

FIG.3illustrates examples of operations300that facilitate processing the landing request received via the bi-directional communication channel130. In some examples, these operations are performed by the control system102, the bi-directional communication system117, and/or both systems operating in cooperation with one another. The operations at block305involve receiving the landing request from the aerial vehicle150. In this regard, in an example, the bi-directional communication system117broadcasts information associated with the landing area105. Examples of this information facilitate the identification of the bi-directional communication channel130for receiving landing requests, information that specifies geospatial coordinates of the landing area105or different landing regions within the landing area105, the operational status of the pseudolites110at the landing area105, the weather conditions at the landing area105, etc. In some examples, the aerial vehicle150communicates the landing request via the bi-directional communication channel130specified in the broadcast information.

The operations at block310involve determining whether the aerial vehicle150is authorized to land at the landing area105. In some examples, the landing area105is restricted to particular aerial vehicles, pilots (if any), and/or passengers. In some examples, the landing request includes identifying information that identifies the aerial vehicle150, pilot, and/or passengers and the control system102determines whether the aerial vehicle150, pilot, and/or passengers are authorized to land at the landing area105based on the identifying information. In some examples, communication of the landing request triggers a series of communications (e.g., to conduct a financial transaction) that facilitate obtaining authorization to land at the landing area105.

If, at block310, the aerial vehicle150is not authorized to land, then the operations at block315are performed. These operations involve communicating information (e.g., via the bi-directional communication channel130) to indicate to the aerial vehicle150that it is not authorized to land. In this case, additional information that would otherwise facilitate landing at the landing area105is not communicated to the aerial vehicle150.

If, at block315, the aerial vehicle150is authorized to land, then the operations at block320are performed. These operations involve communicating pseudolite110encryption key information (e.g., via the bi-directional communication channel130) to the aerial vehicle150. In some examples, the encryption key information specifies the pseudorandom code associated with the pseudolites110at the landing area105. Communication of the pseudorandom code facilitates determining the code-phase and carrier-phase associated with the RF signals125communicated from the pseudolites110. This, in turn, facilitates determining, by the aerial vehicle150, its location relative to the locations of the pseudolites110.

In some examples, the pseudorandom code used by the pseudolite110is changed periodically (e.g., once a day) to require periodic re-authorization to land at the landing area105. Some examples of the pseudolites110output multiple RF signals125, and each RF signal125is associated with a different pseudocode. This, in turn, facilitates the simultaneous authorization of several aerial vehicles150to land at the landing area105without sharing the pseudocode between the aerial vehicles150.

The operations at block325involve communicating navigation information to the aerial vehicle150(e.g., via the bi-directional communication channel130). In this regard, in some examples, the aerial vehicle150communicates its current location to the control system102(e.g., via the bi-directional communication channel130), and the control system102determines a path (e.g., waypoints) the aerial vehicle150should follow that will guide the aerial vehicle150to the landing area105. Some examples of the navigation information specify spatial coordinates (e.g., x, y, and z) for each waypoint and a time at which the aerial vehicle150should reach the waypoint or a speed at which the aerial vehicle150should travel to the waypoint. Some examples of the control system102take the flight paths of other aerial vehicles150into consideration in determining the waypoints.

FIG.4illustrates examples of operations400that facilitate ensuring the integrity of information communicated by the pseudolites110. As noted above, some examples of the NTLS100comprise redundant pseudolites110and redundant monitoring receivers115. The operations at block405involve receiving pseudolite110information via one or more monitoring receivers115. As noted above, each pseudolite110communicates an RF signal125. Some examples of the RF signal125comprise a pseudorandom code that facilitates deriving, by the aerial vehicle150, a code-phase and a carrier-phase that facilitates determining a distance between the aerial vehicle150and the pseudolite110. In some examples, each monitoring receiver115determines the information within the RF signal125(e.g., the code-phase, carrier-phase, pseudorandom code, etc.) and communicates the information to the control system102.

The operations at block410involve determining, based on the information communicated by the monitoring receivers115, whether particular pseudolites110are operating within a nominal operating range. In some examples, when only one monitoring receiver115is used, the control system102compares the values in the information with predetermined values associated with a nominally operating pseudolite110. When the values in the information are within a threshold range of the predetermined values, the pseudolite110is determined to be operating within a nominal operating range.

In some examples, when several monitoring receivers115are used, the values in the information from each monitoring receiver115are compared with the predetermined values, as described above. When the information provided by a majority of the receivers indicates that a particular pseudolite110is operating within a nominal operating range, the pseudolite110is determined to be operating within a nominal operating range. For example, the pseudolite110is determined to be operating within a nominal operating range when the information from two out of three monitoring receivers115indicates the pseudolite110is operating within a nominal operating range. The integrity of this determination is increased by increasing the number of monitoring receivers115. For example, the integrity is increased when nine of ten monitoring receivers115indicate the pseudolite110is operating within a nominal operating range.

If at block410, the pseudolite110is determined to be operating within a nominal operating range, then the operations at block420are performed. These operations involve indicating by the control system102that the pseudolite is operating within a nominal operating range. In some examples, this involves specifying within the RF signal125associated with the pseudolite that the pseudolite110is operating within a nominal operating range. Some examples of an aerial vehicle150monitor this aspect prior to using the pseudolite110for distance determinations. In some examples, the indication is specified via the bi-directional communication system117. For example, the indication is specified in a broadcast communication or in a reply to the landing request referred to above.

If at block410, the pseudolite110is determined to be operating outside of a nominal operating range, then the operations at block425are performed. These operations involve indicating by the control system102that the pseudolite110is operating outside of a nominal operating range. Following the examples above, the indication is specified within the RF signal125associated with the pseudolite110, a broadcast communication by the bi-directional communication system117, and/or in a reply to the landing request. In some examples, when the aerial vehicle150determines, based on the indication, that the pseudolite110is operating outside of a nominal operating range, the aerial vehicle150will not use the RF signal125from that pseudolite110for distance determinations.

The operations at block430involve indicating whether any monitoring receivers115require service. For instance, following the examples above, when the information provided by a majority of the receivers indicates that particular operating state of a pseudolite110(e.g., operating within a nominal operating range), but the information provided by a particular monitoring receiver115indicates a different state of operation (operating outside of a nominal operating range), that monitoring receiver115may be determined, by the control system102, to be operating outside of a nominal operating range. In some examples, the monitoring receiver115may be indicated as such by the control system102. In some examples, the control system102takes the monitoring receiver115offline and/or communicates a service request to a technician to service the monitoring receiver115.

FIG.5illustrates an example of operations500performed by some examples of the devices described herein. The operations at block505involve communicating, by a plurality of pseudolites110distributed proximate a landing area105, a radio frequency (RF) signal that facilitates determining, by the aerial vehicle150and based on a code phase and a carrier phase of the RF signal, its position and velocity relative to the pseudolite110.

The operations at block510involve receiving, by at least one monitoring receiver positioned proximate the landing area105, RF signals from the plurality of pseudolites110.

The operations at block512involve measuring, by the at least one monitoring receiver115, the code phase and the carrier phase associated with each of the plurality of pseudolites110.

The operations at block514involve determining, by the at least one monitoring receiver115and based on the code phase and the carrier phase of the RF signal, corresponding clock bias estimates associated with the RF signals of each pseudolite110.

The operations at block515involve determining, by at least one control system102in communication with the plurality of pseudolites110and the at least one monitoring receiver and based on the RF signals received from the at least one monitoring receiver, whether the plurality of pseudolites110are operating within a nominal operating range.

The operations at block520involve communicating, by a bi-directional RF communication system in communication with the at least one control system102, landing area105information associated with the landing area105to the aerial vehicle150, wherein the landing area105information indicates particular pseudolites110of the plurality of pseudolites110that are operating within a nominal operating range and the clock bias estimate, which further facilitates determining, by the aerial vehicle150it's position and velocity relative to the pseudolites110.

In some examples, the at least one monitoring receiver is one of a plurality of monitoring receivers115in communication with the at least one control system102. These examples involve when the RF signals received by a majority of the plurality of the monitoring receivers115indicate that the particular pseudolite110is in a particular state of operation, determining, by the at least one control system102, the particular pseudolite110is in the particular state of operation.

Some examples of the operations further involve when the RF signals received by the majority of the plurality of monitoring receivers115indicate that the particular pseudolite110is in a particular state of operation, and a particular monitoring receiver indicates that the particular pseudolite110is in a different state of operation, determining, by the at least one control system102, the particular monitoring receiver to be operating outside of a nominal operating range.

Some examples of the operations further involve receiving, by the at least one control system102and via the bi-directional RF communication system, a landing request from the aerial vehicle150, determining, by the at least one control system102, whether the aerial vehicle150is authorized to land at the landing area105, and responsive to determining that the aerial vehicle150is authorized to land at the landing area105, communicating, by the at least one control system102, an encryption key to the aerial vehicle150that facilitates decoding, by the aerial vehicle150, information in the RF signals that facilitates determining, by the aerial vehicle150, distances to the pseudolites110.

In some examples, the landing request specifies a current location of the aerial vehicle150. These examples further involve communicating, by the at least one control system102and to the aerial vehicle150, one or more waypoints that facilitates navigating, by the aerial vehicle150, the aerial vehicle150from the current location to the landing area105.

In some examples, communicating, by the plurality of pseudolites110, the RF signal involves communicating, by the plurality of pseudolites110, an RF signal that comprises location data that specifies a location of the particular pseudolite, integrity data that specifies whether the pseudolite110is operating within a nominal operating range, and a pseudorandom code that facilitates deriving, by the aerial vehicle150, a code-phase and a carrier-phase that facilitate measuring a distance between the aerial vehicle150and the particular pseudolite.

In some examples, each of the plurality of pseudolites comprises a pseudorandom code generator155configured to generate the pseudorandom code. These examples further involve deriving, by the pseudorandom code generator155, timing information from a common clock source151of the NTLS.

In some examples, each of the plurality of pseudolites comprises a pseudorandom code generator155configured to generate the pseudorandom code. These examples further involve operating corresponding pseudorandom code generators155of the plurality of pseudolites asynchronously with respect to one another; and communicating, by the at least one control system, timing information associated with corresponding pseudorandom code generators155of the plurality of pseudolites to the aerial vehicle to facilitate performance of trilateration by the aerial vehicle.

Some examples of the operations involve adjusting, by the at least one control system, timing information associated with the pseudorandom code generators155to minimize differences between respective frequencies and phases of pseudorandom codes generated by the respective pseudorandom code generators155.

In some examples, communicating, by the plurality of pseudolites110distributed proximate the landing area105, the RF signal involves communicating an RF signal that indicates whether a corresponding pseudolite110is operating within a nominal operating range.

FIG.6illustrates an example of a computer system600that can form part of or implement any of the systems and/or devices described above. Some examples of the computer system600include a set of instructions645that the processor605can execute to cause the computer system600to perform any of the operations described above. Some examples of the computer system600operate as a stand-alone device or can be connected, e.g., using a network, to other computer systems or peripheral devices.

In a networked example, some examples of the computer system600operate in the capacity of a server or as a client computer in a server-client network environment, or as a peer computer system in a peer-to-peer (or distributed) environment. Some examples of the computer system600are implemented as or incorporated into various devices, such as a personal computer or a mobile device, capable of executing instructions645(sequential or otherwise), causing a device to perform one or more actions. Further, some examples of the systems described include a collection of subsystems that individually or jointly execute a set, or multiple sets, of instructions to perform one or more computer operations.

Some examples of the computer system600include one or more memory devices610communicatively coupled to a bus620for communicating information. In addition, in some examples, code operable to cause the computer system to perform operations described above is stored in the memory610. Some examples of the memory610are random-access memory, read-only memory, programmable memory, hard disk drive, or any other type of memory or storage device.

Some examples of the computer system600include a display630, such as a liquid crystal display (LCD), organic light-emitting diode (OLED) display, or any other display suitable for conveying information. Some examples of the display630act as an interface for the user to see processing results produced by processor605.

Additionally, some examples of the computer system600include an input device625, such as a keyboard or mouse or touchscreen, configured to allow a user to interact with components of system600.

Some examples of the computer system600include a drive unit615(e.g., flash storage). Some examples of the drive unit615include a computer-readable medium640in which the instructions645can be stored. Some examples of the instructions645reside completely, or at least partially, within the memory610and/or within the processor605during execution by the computer system600. Some examples of the memory610and the processor605include computer-readable media, as discussed above.

Some examples of the computer system600include a communication interface635to support communications via a network650. Some examples of the network650include wired networks, wireless networks, or combinations thereof. Some examples of the communication interface635facilitate communications via any number of wireless broadband communication standards, such as the Institute of Electrical and Electronics Engineering (IEEE) standards 802.11, 802.12, 802.16 (WiMAX), 802.20, cellular telephone standards, or other communication standards.

Accordingly, some examples of the methods and systems described herein are realized in hardware, software, or a combination of hardware and software. Some examples of the methods and systems are realized in a centralized fashion in at least one computer system or in a distributed fashion where different elements are spread across interconnected computer systems. Any kind of computer system or other apparatus adapted for carrying out the methods described herein can be employed.

Some examples of the methods and systems described herein are embedded in a computer program product, which includes all the features that facilitate the implementation of the operations described herein and which, when loaded in a computer system, cause the computer system to perform these operations. A computer program as used herein refers to an expression, in a machine-executable language, code or notation, of a set of machine-executable instructions intended to cause a device to perform a particular function, either directly or after one or more of a) conversion of a first language, code, or notation to another language, code, or notation; and b) reproduction of a first language, code, or notation.

While the systems and methods of operation have been described with reference to certain examples, it will be understood by those skilled in the art that various changes can be made, and equivalents can be substituted without departing from the scope of the claims. Therefore, it is intended that the present methods and systems are not limited to the particular examples disclosed but that the disclosed methods and systems include all embodiments falling within the scope of the appended claims.