Abstract:
A method for operating an amplifier module of a communication satellite involves establishing an undesired state of the amplifier module, storing state data, which indicate the undesired state, in a nonvolatile memory of the amplifier module, after the undesired state has been established, and deactivating the amplifier module after the storage of the state data.

Description:
FIELD OF THE INVENTION 
       [0001]    The invention relates to a method for operating an amplifier module of a communications satellite, and an amplifier module. 
       BACKGROUND OF THE INVENTION 
       [0002]    Traveling wave tube amplifiers (TWTA), which are typically embodied as traveling wave tube modules, are predominantly used as power amplifiers in satellites. These modules comprise a traveling wave tube, which predominantly determines the high-frequency properties, and a power supply, which generates the supply voltages for the traveling wave tubes, a telemetry and/or telecommand interface to the satellite, and a controller. The traveling wave tube module can be supplemented by a preamplifier (also called a channel amplifier), which may also contain a linearizer. The preamplifier can be integrated with the other components in a housing. This combination is typically referred to as a high-frequency power module. 
         [0003]    Traveling wave tube modules and amplifier modules in general can also comprise a protective function component, in which one or more protective functions are embodied, to protect the amplifier from damage, for example, from an excessively low supply voltage, an overload at the outputs of the power supply, an excessively high current on the delay structure, etc. If one of these protective functions is activated, the amplifier module automatically shuts down. 
         [0004]    A ground station is typically informed via telemetry data, which are transmitted from the satellite to the ground station, about the shutdown or also about successful restarting of the amplifier module. However, it cannot be determined from the telemetry data why the device has displayed the malfunction or which protective function was active. 
         [0005]    In general, telemetry data are provided to the satellite as an analog value in the case of analog data or as digital information in the case of status data or already digitized as a digital word from the amplifier module. A system of the satellite reads out the data at regular intervals, wherein the time between two read procedures is typically several seconds (for example, 60 seconds). If an automatic re-start of the amplifier module was successful, this is indicated by a corresponding status telemetry. However, it typically cannot be established from these data which parameter has triggered the protective function. The telemetry data are also not provided promptly as a result of the long read intervals. 
         [0006]    For deep space missions, devices have been developed which, in the case of a malfunction, additionally indicate which parameter has triggered the protective function. However, if the device is completely shut down by the protective function, this information is lost. Furthermore, data of the telemetry are not provided promptly. 
       SUMMARY OF THE INVENTION 
       [0007]    Exemplary embodiments of the invention are directed to a satellite amplifier module, which is easy to maintain. 
         [0008]    One aspect of the invention relates to a method for operating an amplifier module of a communication satellite. 
         [0009]    The amplifier module can comprise an amplifier unit and a controller for activating the amplifier unit. It is to be understood that the communication satellite can have a plurality of amplifier modules, which can each be assigned to one channel of the satellite. 
         [0010]    The amplifier module can be a traveling wave tube module, in which the amplification occurs by way of a traveling wave tube. However, it is also possible that the amplifier module is a semiconductor amplifier module having a semiconductor amplifier. 
         [0011]    According to one embodiment of the invention, the method includes the steps of: establishing an undesired state of the amplifier module; storing state data, which indicate the undesired state, in a nonvolatile memory of the amplifier module, after the undesired state has been established; and deactivating the amplifier module after the storage of the state data. 
         [0012]    It can be considered to be the core of the invention that (shortly) before the deactivation of the amplifier module as a result of a malfunction, i.e., an undesired state, information about the malfunction, i.e., recent state data, are stored in a nonvolatile memory, so that these data are also still available if the amplifier module was disconnected from the power supply of the satellite for a time as a result of the deactivation. 
         [0013]    Accordingly, upon the occurrence of malfunctions the operator of the satellite which fault existed, in particular if the operation of the amplifier module is permanently impaired. In addition, items of information for rapidly occurring procedures (for example, the recognition of a malfunction, an undesired state) are also present in the amplifier module, which are not detected by a slow, regular data query (which can occur every 60 seconds, for example). 
         [0014]    An undesired state can be, for example, an existing fault, a malfunction, or a fault which will occur shortly. An undesired state can be that a specific operating parameter or measured value exceeds or falls below a predefined threshold value. 
         [0015]    The nonvolatile memory is typically embodied for the purpose of withstanding the environmental conditions in outer space, i.e., the nonvolatile memory can be resistant to temperature variations in a large range and/or resistant in relation to radiation. The environmental conditions to which a satellite is subjected in operation normally stop a person skilled in the art from installing a variety of electronic components, which cannot be replaced or can only be replaced with difficulty if the satellite is located in orbit. 
         [0016]    The deactivation of the amplifier module should be understood as a shutdown of the amplifier module in this case, during which the amplifier module is disconnected from a power supply of the satellite, for example. Similarly, the activation of the amplifier module should be understood as turning on or connecting the amplifier module to the power supply of the satellite. 
         [0017]    According to one embodiment of the invention, the undesired state is established by executing a protective function, which is applied to detected parameters of the amplifier module, and which ascertains the undesired state from the detected parameters. The detected parameters can comprise, for example, measured values and/or operating parameters, for example, an input current or an input power of the amplifier module or a regulator voltage, a supply voltage, or a current of a traveling wave tube. The detected parameters can also be settable parameters, for example, configuration parameters, however. 
         [0018]    The protective function can compare, for example, whether the parameter is located above or below a threshold value or is located inside or outside a predefined interval. For example, the protective function can establish that the input power of the amplifier module has sunk below a specific value, which is then recognized as an undesired state. 
         [0019]    According to one embodiment of the invention, the stored state data comprise the type of the protective function. For example, which protective function has responded can be stored in coded form in a digital word. 
         [0020]    According to one embodiment of the invention, the stored state data comprise values of parameters processed by the protective function. These values can be, for example, an operating parameter (for example, the input power) and optionally the associated threshold value. 
         [0021]    According to one embodiment of the invention, the stored state data comprise values of parameters of the amplifier module, which were detected (for example, measured and/or calculated from measured values) (shortly) before the establishment of the undesired state, and/or which were detected (shortly) before the deactivation of the amplifier module. For example, a predefined set of operating parameters and/or settable parameters can be stored as state data. In this context, “short” can mean less than 10 ms or less than 1 ms, for example. 
         [0022]    According to one embodiment of the invention, the method further comprises the steps of: establishing a further undesired state and storing further state data, which relate to the further undesired state, so that the state data and the further state data are stored together in the nonvolatile memory. It is not only possible that the state data for only one (i.e., the most recent) undesired state are stored in the nonvolatile memory, but rather for a plurality of undesired states, for example, a fixed number of previously occurring undesired states. 
         [0023]    If, for example, for operation-technology reasons, the data on an undesired state could not be read out by the ground station, the information is still available, even if further undesired states have occurred in the meantime. 
         [0024]    It is also possible that the stored state data comprise a time value, which indicates a point in time at which the undesired state was established. If multiple sets of state data are stored, the time between two undesired states can also be stored, to be able to assign them chronologically. 
         [0025]    To keep the interruption of the amplifier function of the amplifier module as short as possible, some amplifier modules have an automatic mechanism, which attempts to restart the amplifier module after a short waiting time (for example, a few milliseconds). If the malfunction has then been remedied, the amplifier remains turned on, if the malfunction is still present, the amplifier module turns off permanently. This can also apply if a malfunction occurs again within a short time. Multiple sets of state data can also be stored in the nonvolatile memory in these cases. 
         [0026]    According to one embodiment of the invention, the method further comprises the step of: transmitting the stored state data to a ground station. For example, after the amplifier module has been reactivated or restarted, the information about the undesired state can be read out via a telemetry channel. If the amplifier module was automatically reactivated, the information can also be ready for readout. 
         [0027]    In addition, it is possible that the operating parameters and/or instantaneously set parameters of the amplifier module are read out at intervals of several seconds (for example, every 30 seconds or every 60 seconds) and transmitted to the ground station, even if no undesired state or no malfunction has occurred. 
         [0028]    According to one embodiment of the invention, the stored state data are transmitted when the amplifier module receives a corresponding telecommand from the ground station. For example, the ground station can send a corresponding request (telecommand) to the amplifier module and this then provides the corresponding state data for readout or transmits them via one or more telemetry channels to the ground station. 
         [0029]    According to one embodiment of the invention, the stored state data are automatically transmitted after the amplifier module has been reactivated. For example, after the amplifier module has been restarted via a telecommand or automatically, the state data can be transmitted automatically to the ground station in a reaction to the reactivation. 
         [0030]    According to one embodiment of the invention, the stored state data remain stored in the nonvolatile memory after the transmission to the ground station. The state data can be available automatically for readout over a certain period of time, before they are erased or overwritten with new state data. 
         [0031]    A further aspect of the invention relates to an amplifier module for a communications satellite. A module can be, for example, an assembly having a shared housing or a shared carrier element, on which the components of the amplifier module are fastened and/or using which the components of the amplifier module, for example, a controller, a protective function component, a telemetry component, the amplifier unit, for example, a traveling wave tube or a semiconductor amplifier, etc., can be installed jointly in the satellite. 
         [0032]    According to one embodiment of the invention, the amplifier module comprises an amplifier unit and a controller for activating the amplifier unit. The amplifier unit can be a traveling wave tube. The traveling wave tube can comprise, for example, an emitter, which is designed for generating an electron beam upon application of a voltage; an amplifier section, through which the electron beam runs, and in which a conductor is arranged, and in which a high-frequency signal, which runs through the conductor, can be amplified by the electron beam; and a collector, which is designed to absorb the electron beam and returning it to the emitter. 
         [0033]    The amplifier module can additionally comprise a preamplifier and/or a linearizer, which is installed in a joint assembly with the other components of the amplifier module, for example. 
         [0034]    It is possible that in the case of a traveling wave tube module, two traveling wave tubes are supplied by one power supply and possibly have a shared preamplifier or each traveling wave tube individually has a preamplifier. 
         [0035]    Furthermore, the controller comprises a nonvolatile, writable memory, which is designed for storing state data of the amplifier module when the amplifier module is not energized by an external power supply of the satellite. The nonvolatile memory can be provided in a special chip, for example, which can be installed separately from the electronics of the controller in the amplifier module. 
         [0036]    The nonvolatile memory and/or the controller can be housed in the power supply (or in the housing of the power supply) of the amplifier module. The nonvolatile memory and/or the controller can also be housed in a preamplifier and/or linearizer, or also partially in the power supply and partially in the preamplifier and/or linearizer, however. 
         [0037]    To be able to provide items of information about an undesired state of the amplifier module even when it has been turned off or deactivated, the controller is designed for executing the operating method as described above and hereafter. It is to be understood that features of the amplifier module can also be features of the method and vice versa. 
         [0038]    According to one embodiment of the invention, the controller comprises a telemetry component, which is designed for detecting operating parameters and/or settable parameters of the amplifier module as state data. The telemetry component can activate measuring sensors and provide the obtained measured values in digital form, for example. 
         [0039]    According to one embodiment of the invention, the controller comprises a protective function component, which is designed for analyzing operating parameters and/or settable parameters of the amplifier module as state data, to determine an undesired state of the amplifier module. For example, the telemetry component may provide these parameters to the protective function component. 
         [0040]    According to one embodiment of the invention, the amplifier module further comprises a telecommand interface, which is designed for receiving a telecommand from a ground station, which triggers a transmission of state data stored in the nonvolatile memory. For example, this telecommand interface can be an external interface of the amplifier module, which the amplifier module can use to communicate with a further controller of the satellite. 
         [0041]    In summary, such an operating method and such an amplifier module can have the following advantages: In the event of a malfunction of the amplifier module, an item of information is available as to which protective circuit or protective function has responded. In the event of repeated malfunctions, it can be established whether the same cause always existed. Telemetry data detected promptly from the occurrence of the malfunction can provide information about the operating state of the amplifier module at the point in time of the fault. This information can be used for the fault search, to localize the cause of the fault. 
         [0042]    Exemplary embodiments of the invention will be described in greater detail hereafter with reference to the appended figures. 
     
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         [0043]      FIG. 1  shows a schematic view of a communications satellite according to one embodiment of the invention. 
           [0044]      FIG. 2  shows a schematic view of an amplifier module according to one embodiment of the invention. 
           [0045]      FIG. 3  shows a flow chart for a method for operating an amplifier module according to one embodiment of the invention. 
       
    
    
       [0046]    Fundamentally, identical or similar parts are provided with identical reference signs. 
       DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS 
       [0047]      FIG. 1  shows a communications satellite  10  having an antenna  12 , a main control unit or main controller  14 , and a power supply  16 , which is supplied with energy by a solar panel  18 , for example. 
         [0048]    Furthermore, the communication satellite  10  has an amplifier module  20  in the form of a traveling wave tube module  20 . Only one channel of the communication satellite  10  is shown in  FIG. 1 , typically a communication satellite  10  can have multiple channels, which can each comprise a traveling wave tube module  20 . 
         [0049]    The communication satellite  10  can receive a high-frequency signal  22  via the antenna  12  and relay it to the traveling wave tube module  20 . The high-frequency signal  22  is amplified therein to form an amplified high-frequency signal  24  and can be emitted again via the antenna  12  (or a further antenna). The traveling wave tube module  20  is supplied with voltage  26  via the power supply  16  in this case. Furthermore, the traveling wave tube module  20  can be activated by the control unit  14  and can receive telecommands  28 , for example, which have been received via the antenna  12  and analyzed by the control unit  14 , for example. 
         [0050]      FIG. 2  shows a traveling wave tube module  20  in greater detail as a block diagram. The traveling wave tube module  20  comprises a traveling wave tube  30 , which receives the high-frequency signal  22  via a high-frequency input  32  and outputs the amplified high-frequency signal  24  via a high-frequency output  34 . 
         [0051]    The traveling wave tube  30  comprises an emitter  36 , using which an electron beam  38  can be generated, and a collector  40 , which absorbs the electron beam  38  again. In this manner, the electric current from the electron beam  38  can be returned back to the emitter  36 . An amplifier region  42 , in which the high-frequency signal  22  is amplified by the electron beam  38 , lies between the emitter and the collector  38 . The high-frequency signal  22  is sent by way of a coiled conductor  44  through the traveling wave tube  30  in this case. 
         [0052]    Between the high-frequency input  32  and the traveling wave tube  30 , the traveling wave tube module  20  can have a channel amplifier and/or linearizer  46 , using which the unamplified high-frequency signal  22  can be pre-amplified and/or linearized, before it is supplied to the traveling wave tube  30 . 
         [0053]    The remaining components of the traveling wave tube module  20  represent the power supply for the traveling wave tube  30 . 
         [0054]    The traveling wave tube  30  is supplied by the high-voltage generator  50  with a plurality of supply voltages  52 , for example, an anode voltage, one or more collector voltages, a cathode voltage of the emitter, etc. 
         [0055]    A supply voltage  54  for the high-voltage generator  50  is provided by a pre-regulator and filter  56 , which converts the voltage  26  from the power supply  16  of the satellite  10  to a constant and uniform DC voltage. 
         [0056]    The traveling wave tube module  20  furthermore comprises a controller  60 , which comprises a central component  62 , a telemetry and telecommand interface  64 , a protective function component  66 , a telemetry component  68 , and a nonvolatile data memory  70 . The controller  60  or its components  62 ,  64 ,  66 ,  68 ,  70  are supplied with voltage by an auxiliary voltage supply  72 , which is supplied with a voltage  74  by the pre-regulator and filter  56 . 
         [0057]    In the telemetry component  68 , the telemetry data or operating parameters and settable parameters  80  of the traveling wave tube module  20  are detected and collected. For example, the telemetry component  68  can detect sensor data from the high-voltage generator  50 , the pre-regulator and filter  56 , and the channel amplifier and/or linearizer  46  and convert them into digital form. 
         [0058]    In the protective function component  66 , protective functions and/or alarm functions are executed, which check whether detected parameters  80  move in the desired scope. For this purpose, the protective function component  66  can detect these parameters directly and/or can receive them provided by the telemetry component  68 . Examples of protective functions are undervoltage protection, overload protection, etc. 
         [0059]    Fixedly defined data can be stored or present data, for example, operating parameters and settable parameters  80 , can be stored as state data  82  in the nonvolatile data memory  70  or memory component  70 . If a protective function is activated, the controller  60  can determine the triggering parameter  70 , optionally record all telemetry data and store this information in the data memory  70 . Since it is a non-volatile memory  70 , the state data  82  are also available after the amplifier module  20  has been restarted or has automatically restarted and was de-energized for some time. 
         [0060]    The telemetry and telecommand interface  64  is connected to the other components  14  of the satellite  10  and therefore represents a connection to the control station on the ground. Via the interface, the amplifier module  20  or the controller  60  can receive telecommands, for example, control commands, or the amplifier module  20  or the controller  64  can deliver data about the operating state. 
         [0061]    The central component  62  of the controller  64  can regulate and monitor all procedures, for example, the triggering of the protective function, the storage and readout of the state data, etc. 
         [0062]      FIG. 3  shows a flow chart for operating the amplifier module  20 . 
         [0063]    An undesired state of the amplifier module  20  is established in step  90 . For this purpose, the protective function module can respectively compare detected parameters  70 , which originate from the telemetry component  68 , for example, to a threshold value and trigger an alarm if the values exceed or fall below the thresh-old value. 
         [0064]    For example, an alarm for a voltage undersupply can be triggered if the input power of the pre-regulator and filter  56  falls below a specific value. An alarm can also be triggered for an overvoltage if, for example, the collector voltage of the traveling wave tube exceeds a specific value. 
         [0065]    After the undesired state has been established, in step  92 , state data  81  that indicate the undesired state are stored in the nonvolatile memory  70 . This can be performed, for example, by the central component  62  of the controller  64 , which receives the alarm of the protective function and reads out the state data  82  to be stored or the associated parameters. 
         [0066]    The stored state data  82  can comprise the type of the protective function and/or the point in time at which the protective function was triggered. For example, the protective functions can be numbered and the corresponding number can be stored in the state data  82 . 
         [0067]    The stored state data  82  can comprise values of parameters  70  of the amplifier module  20 , which were processed by the protective function, for example, the in-put power or the cathode voltage. 
         [0068]    Furthermore, the stored state data  82  can comprise values of further, other parameters  70  of the amplifier module  20 , which were detected before the establishment of the undesired state and/or which were detected before the deactivation of the amplifier module  20 . For example, every time when state data  82  are stored, all voltage and current values, which were detected for the traveling wave tube  30 , can also be stored. 
         [0069]    After the storage of the state data  82 , in step  94 , the amplifier module  20  is deactivated. For example, the central component  62  of the controller  60  can instruct the pre-regulator and filter  56  to disconnect the amplifier module  20  from its supply voltage. 
         [0070]    In step  96 , the amplifier module  20  is reactivated, for example, via an external controller  14  of the satellite  10 , which executes the starting procedure automatically after a certain time, for example, or is prompted thereto by a corresponding telecommand of the ground station. 
         [0071]    In step  98 , the stored state data  82  are transmitted to the ground station. This can be prompted, for example, in that the controller  64  receives a corresponding telecommand  28  from the ground station and/or the controller  64  automatically transmits the stored state data  82  after the amplifier module  20  has been reactivated. For this purpose, the controller  64  can check in the nonvolatile memory  70 , for example, after the starting of the amplifier module  20 , as to whether non-transmitted state data  82  are present, and can subsequently transmit them to the ground station. 
         [0072]    In addition, it is to be noted that “comprising” does not exclude other elements or steps and “a” or “an” does not exclude a plurality. Furthermore, it is to be noted that features or steps which have been described with reference to one of the above exemplary embodiments can also be used in combination with other features or steps of other above-described exemplary embodiments. Reference signs in the claims are not to be considered to be a restriction. 
         [0073]    The foregoing disclosure has been set forth merely to illustrate the invention and is not intended to be limiting. Since modifications of the disclosed embodiments incorporating the spirit and substance of the invention may occur to persons skilled in the art, the invention should be construed to include everything within the scope of the appended claims and equivalents thereof.