Transponders, communication systems, processing methods, and programs

Abstract

To provide a transponder capable of detecting radio waves unnecessary for communication in a band used for the communication and reducing the scale of hardware in a satellite performing wireless communication.SOLUTION: A transponder installed in a satellite that detects unnecessary radio waves in a band used for communication and performs wireless communication includes IQ detection means that detects I and Q signals generated from a received signal, FFT processing means that performs fast Fourier transform on at least one of the signal before IQ decomposition detected by the IQ detection means, the I signal, and the Q signal, and carrier recovery means that detects a carrier component from the I signal and the Q signal after back-diffusion processing.SELECTED DRAWING: Figure 6

Description

Technical Field

[0001] The present disclosure relates to a transponder, a communication system, a processing method, and a program.

Background Art

[0002] In recent years, the utilization of artificial satellites has expanded, and the number of satellite launches by each country, such as large-scale LEO constellations of private companies, has been increasing. As a result, wireless communication using satellites has been carried out in various fields. However, for example, as shown in FIG. 9, there is a problem that radio waves in an unnecessary frequency band in the communication channel, such as radio waves from surrounding satellites or ground stations operating them, interfere with the communication (that is, become noise or interference waves). Patent Document 1 discloses a technology related to a communication system as a related technology.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Incidentally, in satellites that perform wireless communication, when it comes to detecting unwanted radio waves such as interference waves, noise, and other jamming waves in the communication band, it is common practice to add hardware that performs frequency analysis, separate from the transponder that transmits and receives signals. In other words, the hardware that performs frequency analysis has functions similar to those of the transponder, which processes the reception of radio waves into high-frequency signals by the antenna, down-converts those high-frequency signals to an intermediate frequency, and performs AD conversion to generate orthogonal signals, the I and Q signals. As a result, the scale of the hardware in a satellite that performs wireless communication becomes larger, and the weight of the satellite increases. Consequently, the energy required to launch the satellite and the energy required for processing on the satellite increase. Therefore, there is a need for technology that can detect radio waves unnecessary for communication within the bandwidth used for communication, thereby reducing the scale of hardware in satellites that perform wireless communication.

[0005] Each aspect of this disclosure aims to provide a transponder, a communication system, a processing method, and a program that can solve the above-mentioned problems. [Means for solving the problem]

[0006] To achieve the above objective, according to one aspect of this disclosure, the transponder is: A transponder installed on a satellite performing wireless communication, which detects radio waves unnecessary for the communication in the bandwidth used for communication, comprises: a receiving system high-frequency processing means for amplifying an analog received signal and converting the amplified received signal into an analog IF (Intermediate Frequency) signal; an A / D (Analog to Digital) conversion means for converting the analog IF signal into a digital IF signal; an IQ detection means for decomposing the received signal into an I signal and a Q signal, detecting the I signal and the Q signal, and outputting at least one of the signal before IQ decomposition, the I signal, and the Q signal; an FFT processing means configured by an FPGA (Field Programmable Gate Array), which performs a Fast Fourier Transform on at least one of the signal before IQ decomposition detected by the IQ detection means, the I signal, and the Q signal; and a carrier regeneration means for detecting a carrier component from the I signal and the Q signal after despreading processing, wherein the receiving system high-frequency processing means, the A / D conversion means, and the IQ detection means are commonly used in the processing for executing the Fast Fourier Transform and the processing for identifying commands. .

[0007] To achieve the above objective, according to another aspect of the present disclosure, the communication system comprises the transponder and a satellite-borne computer that executes commands identified based on carrier components detected by the carrier regeneration means and analyzes the results of a fast Fourier transform performed by the FFT processing means.

[0008] To achieve the above objective, according to another aspect of this disclosure, the processing method is: A transponder installed on a satellite performing wireless communication, which detects radio waves unnecessary for the communication in the bandwidth used for communication, and which comprises a receiving system high-frequency processing means, an A / D (Analog to Digital) conversion means, an IQ detection means, an FFT processing means composed of an FPGA (Field Programmable Gate Array), and a carrier regeneration means, wherein the receiving system high-frequency processing means amplifies the analog received signal and converts the amplified received signal to an analog IF (Intermediate) The process includes: converting the IF signal to a frequency (F) signal; the A / D conversion means converting the analog IF signal to a digital IF signal; the IQ detection means decomposing the received signal into an I signal and a Q signal, thereby detecting the I signal and the Q signal, and outputting at least one of the pre-IQ decomposition signal, the I signal, and the Q signal; the FFT processing means performing a Fast Fourier Transform on at least one of the pre-IQ decomposition signal, the I signal, and the Q signal detected by the IQ detection means; and the carrier regeneration means detecting the carrier component from the I signal and the Q signal after despreading processing. The receiving system high-frequency processing means, the A / D conversion means, and the IQ detection means are commonly used in the process of identifying the processing and commands for performing the Fast Fourier Transform. .

[0009] To achieve the above objectives, according to another aspect of this disclosure, the program is: A program for determining the circuit configuration in an FPGA, which is programmable hardware that includes a receiving system high-frequency processing means, an A / D (Analog to Digital) conversion means, an IQ detection means, an FFT processing means composed of an FPGA (Field Programmable Gate Array), and a carrier regeneration means, which detects radio waves unnecessary for the communication in the bandwidth used for communication, and is installed on a satellite that performs wireless communication. The FPGA is configured to perform the following: the receiving system high-frequency processing means amplifies the analog received signal and converts the amplified received signal into an analog IF (Intermediate Frequency) signal; the A / D conversion means converts the analog IF signal into a digital IF signal; the IQ detection means decomposes the received signal into an I signal and a Q signal, detects the I signal and the Q signal, and outputs at least one of the pre-IQ decomposition signal, the I signal, and the Q signal; the FFT processing means performs a Fast Fourier Transform on at least one of the pre-IQ decomposition signal, the I signal, and the Q signal detected by the IQ detection means; and the carrier regeneration means detects the carrier component from the I signal and the Q signal after despreading processing. The receiving system high-frequency processing means, the A / D conversion means, and the IQ detection means are commonly used in the process of identifying commands for performing the Fast Fourier Transform. .

[0010] To achieve the above objectives, according to another aspect of this disclosure, the program is: A transponder installed on a satellite performing wireless communication, which detects radio waves unnecessary for the communication in the bandwidth used for communication, is configured as an FPGA (Field Programmable Gate Array) and has FFT processing means that performs a Fast Fourier Transform on at least one of the detected signal before IQ decomposition, the I signal and the Q signal, and includes a computer including receiving system high frequency processing means, A / D (Analog to Digital) conversion means, IQ detection means and carrier regeneration means, the receiving system high frequency processing means amplifies the analog received signal and converts the amplified received signal to an analog IF (Intermediate) The receiving system high-frequency processing means, the A / D conversion means converts the analog IF signal into a digital IF signal, the IQ detection means decomposes the received signal into the I signal and the Q signal generated from the received signal, detects the I signal and the Q signal, and outputs at least one of the signals before IQ decomposition, the I signal and the Q signal, and the carrier regeneration means detects the carrier component from the I signal and the Q signal after despreading processing, and the receiving system high-frequency processing means, the A / D conversion means and the IQ detection means are commonly used in the process of identifying the processing and commands for performing the Fast Fourier Transform. . [Effects of the Invention]

[0011] According to each aspect of this disclosure, it is possible to detect radio waves in the bandwidth used for communication that are not needed for the communication, and to reduce the scale of hardware in the satellite that performs wireless communication. [Brief explanation of the drawing]

[0012] [Figure 1] This figure shows an example of the configuration of a communication system according to an embodiment of the present disclosure. [Figure 2] This figure shows an example of the spectrum after processing by the FFT processing unit according to the embodiment of the present disclosure. [Figure 3] This figure shows an example of reception processing performed by a communication system according to an embodiment of the present disclosure. [Figure 4] This figure shows an example of the transmission process performed by the communication system according to the embodiment of this disclosure. [Figure 5] This figure shows an example of the configuration of a communication system being compared. [Figure 6] This figure shows the minimum configuration of a transponder according to the embodiments of this disclosure. [Figure 7] This figure shows an example of the processing flow of a minimal transponder according to an embodiment of the present disclosure. [Figure 8] This is a schematic block diagram showing the configuration of a computer according to at least one embodiment. [Figure 9] This diagram illustrates the concept of interference in communications. [Modes for carrying out the invention]

[0013] The embodiments will be described in detail below with reference to the drawings. <Embodiment> FIG. 1 is a diagram showing an example of the configuration of the communication system 1 according to an embodiment of the present disclosure. As shown in FIG. 1, the communication system 1 includes a satellite-mounted antenna 10, a transponder 20, and a satellite-mounted computer 30. The communication system 1 is a satellite communication system that detects radio waves unnecessary for the communication in the band used for communication and performs wireless communication.

[0014] The satellite-mounted antenna 10 receives electromagnetic waves (hereinafter referred to as "radio waves") arriving from the outside of the communication system 1. Then, the satellite-mounted antenna 10 converts the received radio waves into a received signal, which is an electrical signal. Note that the received signal is an RF (Radio Frequency) received signal in the RF frequency band. Further, the satellite-mounted antenna 10 converts a transmission signal, which is an electrical signal received from the transponder 20, into radio waves. Then, the satellite-mounted antenna 10 transmits radio waves from the communication system 1 to an external transmission destination. Note that the radio waves are radio waves in the RF frequency band.

[0015] As shown in FIG. 1, the transponder 20 includes a receiving system high-frequency unit 201, a digital signal processing unit 202, and a transmitting system high-frequency unit 203. As shown in FIG. 1, the receiving system high-frequency unit 201 includes a LNA (Low Noise Amplifier) 201a and a downconverter 201b. The LNA 201a amplifies the RF received signal. The downconverter 201b converts the RF signal in the RF frequency band after amplification by the LNA 201a into an IF (Intermediate Frequency) signal (intermediate frequency signal).

[0016] As shown in FIG. 1, the digital signal processing unit 202 includes an A / D (Analog to Digital) converter 2021, an FPGA (Field Programmable Gate Array) 2022, and a D / A (Digital to Analog) converter 2023.

[0017] The A / D converter 2021 converts the analog IF signal after frequency conversion by the downconverter 201b into a digital IF signal.

[0018] As shown in Figure 1, FPGA2022 comprises an IQ detection unit 2022a, a PN (PSEUDO Noise) code synchronization unit 2022b, a carrier regeneration unit 2022c, a command demodulation unit 2022d, an FFT (Fast Fourier Transform) processing unit 2022e, a modulated signal processing unit 2022f, and an IQ modulation unit 2022g.

[0019] The IQ detection unit 2022a identifies the modulation scheme based on the digital IF signal converted by the A / D converter 2021. For example, based on the IF signal, the IQ detection unit 2022a determines whether the modulation scheme is wireless communication using a spread spectrum method. An example of a spread spectrum method is CDMA (Code Division Multiplex Access). The IQ detection unit 2022a decomposes the digital IF signal converted by the A / D converter 2021 into orthogonal components of the I channel and Q channel (i.e., the I signal and the Q signal). In other words, the IQ detection unit 2022a detects the I signal and Q signal generated from the received signal. The IQ detection unit 2022a outputs at least one of the signals before IQ decomposition, the I signal, and the Q signal to the FFT processing unit 2022e.

[0020] Furthermore, the IQ detection unit 2022a detects a portion of the signal, including the PN code, from both the I signal and the Q signal, and outputs the detected signal to the PN code synchronization unit 2022b. The PN code is a code that indicates how the transmitter that transmitted the radio waves received by the satellite-mounted antenna 10 modulates each channel differently. Here, the embodiment is described using the PN code as an example, but another spreading code may be used instead of the PN code. An example of another spreading code is the Barker code.

[0021] Furthermore, in the case of wireless communication using spread spectrum, the IQ detection unit 2022a and the PN code synchronization unit 2022b perform despreading processing to cancel out the PN code in a portion of the signal that includes the PN code. In other words, the IQ detection unit 2022a generates a signal in which the PN code in the I signal and Q signal has been canceled out. The IQ detection unit 2022a then outputs the I signal and Q signal, after despreading processing, to the carrier regeneration unit 2022c. Note that the processing performed by the IQ detection unit 2022a may be implemented using HDL (Hardware Description Language). Examples of HDL include Verilog-HDL and VHDL.

[0022] Furthermore, in the case of wireless communication using a spread spectrum method, the PN code synchronization unit 2022b performs correlation processing to confirm the modulation method indicated by the PN code from a portion of the signal containing the PN code detected by the IQ detection unit 2022a from the I signal and Q signal respectively, and performs a cancellation process on the I signal and Q signal before the despreading process to cancel out the PN code corresponding to the modulation method indicated by the confirmed PN code. The PN code synchronization unit 2022b outputs a portion of the signal corresponding to the I signal and Q signal, respectively, after the PN code cancellation process, to the IQ detection unit 2022a.

[0023] Furthermore, in the case of wireless communication using spread spectrum, the PN code synchronization unit 2022b outputs a PN code corresponding to the destination to the IQ modulation unit 2022g. The processing performed by the PN code synchronization unit 2022b may be implemented using HDL.

[0024] The carrier regeneration unit 2022c detects the carrier component from the I and Q signals after despreading processing and outputs the detected carrier component to the command demodulation unit 2022d. The processing performed by the carrier regeneration unit 2022c may be implemented using HDL.

[0025] The command demodulation unit 2022d identifies the command indicated by the carrier component output by the carrier regeneration unit 2022c. The command demodulation unit 2022d outputs a signal to the satellite-borne computer 30 instructing it to execute the identified command. The processing performed by the command demodulation unit 2022d may be implemented using HDL.

[0026] The FFT processing unit 2022e performs an FFT (Fast Fourier Transform) on at least one of the signals output by the IQ detection unit 2022a—the signal before IQ decomposition and despreading, the I signal, and the Q signal—and outputs the conversion result (i.e., the spectrum showing the frequency components after conversion) to the satellite-borne computer 30. The processing performed by the FFT processing unit 2022e may be implemented using HDL.

[0027] Figure 2 shows an example of the spectrum after processing by the FFT processing unit 2022e according to an embodiment of the present disclosure. In Figure 2, part (a) shows the target wave (i.e., the frequency band component necessary for communication using radio waves modulated according to the channel) and the interfering wave (i.e., the component unnecessary for communication) as they change over time. The FFT processing unit 2022e outputs the information of the processed spectrum as a conversion result to the satellite-borne computer 30.

[0028] The modulation signal processing unit 2022f generates I signal data and Q signal data for a signal obtained by adding a packet of spectrum analysis result information to the end of the telemetry packet transmitted from the satellite-borne computer 30. An example of a telemetry packet is a packet indicating settings and processing details that the user has determined should be improved based on the results obtained when the satellite-borne computer 30 performs processing in response to a command. An example of a spectrum analysis result information packet is a packet indicating information including unwanted components that were included in the spectrum. The processing performed by the modulation signal processing unit 2022f may be implemented using HDL.

[0029] The IQ modulation unit 2022g adds PN codes to the I signal data and Q signal data generated by the modulation signal processing unit 2022f, and then combines them. The processing performed by the IQ modulation unit 2022g may be implemented using HDL.

[0030] The D / A converter 2023 converts the combined digital signal output by the IQ modulation unit 2022g into an analog signal.

[0031] As shown in Figure 1, the high-frequency section 203 of the transmitting system includes an upconverter 203a and a PA (Power Amplifier) ​​203b. The upconverter 203a converts the analog signal output by the D / A converter 2023 into an RF transmission signal in the RF frequency band. The PA 203b amplifies the RF transmission signal.

[0032] The satellite-borne computer 30 executes processing in response to commands received from the satellite-borne transceiver 20. The satellite-borne computer 30 also analyzes the spectrum received from the satellite-borne transceiver 20. Then, based on the results obtained from the processing performed by the satellite-borne computer 30 in response to the command, the satellite-borne computer 30 adds a packet containing information on the spectrum analysis results to the end of a packet indicating settings and processing details that the user has determined should be improved, and transmits the resulting packet (i.e., a signal with the spectrum analysis result packet added to the end of the telemetry packet) to the satellite-borne transceiver 20.

[0033] Figure 3 shows an example of the receiving process performed by the communication system 1 according to an embodiment of this disclosure. Figure 4 shows an example of the transmitting process performed by the communication system 1 according to an embodiment of this disclosure. Next, the transmitting and receiving processes performed by the communication system 1 will be described with reference to Figures 3 and 4.

[0034] (Receiving processing) First, let's explain the reception process performed by the communication system 1 shown in Figure 3. The satellite-mounted antenna 10 receives radio waves arriving from outside the communication system 1. Then, the satellite-mounted antenna 10 converts the received radio waves into an RF received signal, which is an electrical signal (step S1).

[0035] LNA201a amplifies the RF received signal (step S2). Downconverter 201b converts the RF signal in the RF frequency band amplified by LNA201a into an IF signal (step S3).

[0036] The A / D converter 2021 converts the analog IF signal, which has been frequency-converted by the downconverter 201b, into a digital IF signal (step S4).

[0037] The IQ detection unit 2022a decomposes the digital IF signal converted by the A / D converter 2021 into orthogonal components of the I channel and Q channel (i.e., the I signal and the Q signal) (step S5). The IQ detection unit 2022a outputs at least one of the signals before IQ decomposition, the I signal, and the Q signal to the FFT processing unit 2022e.

[0038] The FFT processing unit 2022e performs an FFT on at least one of the signals output by the IQ detection unit 2022a, which is the signal before IQ decomposition, the I signal, and the Q signal (step S6).

[0039] The IQ detection unit 2022a identifies the modulation scheme based on the digital IF signal after conversion by the A / D converter 2021. For example, the IQ detection unit 2022a determines, based on the IF signal, whether or not the modulation scheme is wireless communication using a spread spectrum method (step S7).

[0040] If the IQ detection unit 2022a determines that the modulation scheme is wireless communication using a spread spectrum method (YES in step S7), it detects a portion of the signal, including the PN code, from each of the I signal and Q signal, and outputs the detected signal to the PN code synchronization unit 2022b. The FFT processing unit 2022e outputs the FFT conversion result (i.e., the spectrum showing the frequency components after conversion) to the satellite-borne computer 30.

[0041] The PN code synchronization unit 2022b performs correlation processing to confirm the modulation method indicated by the PN code from a portion of the signal containing the PN code detected by the IQ detection unit 2022a from the I signal and the Q signal, respectively, and then performs a cancellation process on the I signal and the Q signal to cancel out the PN code corresponding to the modulation method indicated by the confirmed PN code (step S8). The PN code synchronization unit 2022b outputs a portion of the signal corresponding to the I signal and the Q signal after the PN code cancellation process to the IQ detection unit 2022a.

[0042] The IQ detection unit 2022a and the PN code synchronization unit 2022b perform despreading processing on a portion of the signal containing the PN code, canceling out the PN code (step S9). In other words, the IQ detection unit 2022a generates signals in which the PN code in the I signal and Q signal has been canceled out. The IQ detection unit 2022a then outputs the I signal and Q signal (in this case, the I signal and Q signal after despreading processing) to the carrier regeneration unit 2022c.

[0043] The carrier regeneration unit 2022c detects the carrier component from the I signal and Q signal (step S10), and outputs the detected carrier component to the command demodulation unit 2022d.

[0044] Furthermore, if the IQ detection unit 2022a determines that the modulation scheme is not wireless communication using a spread spectrum method (NO in step S7), it outputs the I signal and Q signal to the carrier regeneration unit 2022c, and the carrier regeneration unit 2022c performs the processing in step S10. In other words, if the IQ detection unit 2022a determines that the modulation scheme is not wireless communication using a spread spectrum method, it does not perform the processing in steps S7 to S9.

[0045] The command demodulation unit 2022d identifies the command indicated by the carrier component output by the carrier regeneration unit 2022c (step S11). The command demodulation unit 2022d outputs a signal to the satellite-borne computer 30 instructing it to execute the identified command.

[0046] The satellite-borne computer 30 performs processing according to commands received from the satellite-borne transceiver 20. The satellite-borne computer 30 also analyzes the spectrum received from the satellite-borne transceiver 20.

[0047] (Transmission process) Next, the transmission process performed by the communication system 1 shown in Figure 4 will be described. The satellite-mounted computer 30, in response to a command, performs processing and, based on the results obtained, adds a packet indicating the spectrum analysis results to the end of a packet indicating the settings and processing content that the user has determined should be improved. The satellite-mounted transceiver 20 then transmits the modified packet (i.e., a signal with the spectrum analysis results packet added to the end of the telemetry packet) to the satellite-mounted transceiver 20. The transmission process performed by the communication system 1 described below will be explained assuming that the modulation method is spread spectrum wireless communication.

[0048] The modulation signal processing unit 2022f generates I signal data and Q signal data for the signal obtained by adding a packet of information on the spectrum analysis result to the end of the telemetry packet transmitted from the satellite-borne computer 30 (step S21).

[0049] The PN code synchronization unit 2022b outputs a PN code corresponding to the destination to the IQ modulation unit 2022g.

[0050] The IQ modulation unit 2022g adds a PN code to the I signal data and Q signal data generated by the modulation signal processing unit 2022f, and then combines them (step S22).

[0051] The D / A converter 2023 converts the combined digital signal output by the IQ modulation unit 2022g into an analog signal (step S23).

[0052] The upconverter 203a converts the analog signal output by the D / A converter 2023 into an RF transmission signal in the RF frequency band (step S24). PA203b amplifies the RF transmission signal (step S25).

[0053] The satellite-mounted antenna 10 converts the RF transmission signal, which is an electrical signal received from the transponder 20, into radio waves (step S26). Then, the satellite-mounted antenna 10 transmits the radio waves from the communication system 1 to an external destination.

[0054] In the embodiments of this disclosure described above, a portion of the transponder 20 was described as being implemented by FPGA2022. However, the transponder 20 may be implemented by hardware other than FPGA2022. Examples of hardware other than FPGA2022 include PLD (Programmable Logic Device), CPU (Central Processing Unit), and ASIC (Application Specific Integrated Circuit).

[0055] (advantage) The communication system 1 according to the embodiment of the present disclosure has been described above. Now, a comparative communication system 1a will be described. Figure 5 shows an example of the configuration of the comparative communication system 1a. As shown in Figure 5, the communication system 1a comprises a satellite-mounted antenna 10, a transponder 20a, a satellite-mounted computer 30, and an FFT processing unit 40.

[0056] The satellite-mounted antenna 10 and satellite-mounted computer 30 of communication system 1a are identical to those of communication system 1. Unlike transponder 20, transponder 20a includes, as shown in Figure 5, a receiving high-frequency section 201, a digital signal processing section 202, an A / D converter 2021, an IQ detection section 2022a1, a PN code synchronization section 2022b1, a carrier regeneration section 2022c1, a command demodulation section 2022d1, a modulation signal processing section 2022f1, an IQ modulation section 2022g1, and a D / A converter 2023.

[0057] Furthermore, the receiving high-frequency section 201, digital signal processing section 202, A / D converter 2021, IQ detection section 2022a1, PN code synchronization section 2022b1, carrier regeneration section 2022c1, command demodulation section 2022d1, modulation signal processing section 2022f1, IQ modulation section 2022g1, and D / A converter 2023 of the transponder 20a perform the same processing as the receiving high-frequency section 201, digital signal processing section 202, A / D converter 2021, IQ detection section 2022a, PN code synchronization section 2022b, carrier regeneration section 2022c, command demodulation section 2022d, modulation signal processing section 2022f, IQ modulation section 2022g, and D / A converter 2023 of the transponder 20. However, the IQ detection unit 2022a1, PN code synchronization unit 2022b1, carrier regeneration unit 2022c1, command demodulation unit 2022d1, modulated signal processing unit 2022f1, and IQ modulation unit 2022g1 are not necessarily implemented using FPGAs.

[0058] Furthermore, the FFT processing unit 40 includes an FFT processing unit 401 in addition to the receiving high-frequency unit 201, A / D converter 2021, and IQ detection unit 2022a1 provided by the transponder 20a. The FFT processing unit 401 performs the same processing as the FFT processing unit 2022e. However, the FFT processing unit 401 is not necessarily implemented using an FPGA.

[0059] As described above, the communication system 1a being compared has a configuration that overlaps with the receiving high-frequency section 201, A / D converter 2021, and IQ detection section 2022a1 of the transponder 20a and the receiving high-frequency section 201, A / D converter 2021, and IQ detection section 2022a1 of the FFT processing unit 40.

[0060] In contrast, communication system 1 includes a common receiving high-frequency unit 201, an A / D converter 2021, and an IQ detection unit 2022a for both FFT processing and command identification. This is achieved by configuring the FFT processing unit 2022e in FPGA 2022. Therefore, communication system 1 can reduce the hardware equivalent to the receiving high-frequency unit 201, the A / D converter 2021, and the IQ detection unit 2022a1, as well as the material equivalent to the enclosure of the FFT processing unit 40, compared to communication system 1a.

[0061] In other words, the aforementioned communication system 1 can detect radio waves unnecessary for communication within the bandwidth used for communication, thereby reducing the size of the hardware in the satellite performing wireless communication. As a result, the communication system 1 can reduce the weight of the satellite.

[0062] In one embodiment of this disclosure, the transmission process performed by the communication system 1 is described as wireless communication using a spread spectrum modulation scheme. However, in another embodiment of this disclosure where the modulation scheme is wireless communication that does not use a spread spectrum modulation scheme, the PN code synchronization unit 2022b1 does not perform the process of adding a PN code (i.e., the process of step S22 in Figure 4). Furthermore, in another embodiment of this disclosure where the modulation scheme is wireless communication that does not use a spread spectrum modulation scheme, the communication system 1 does not need to include the PN code synchronization unit 2022b1.

[0063] Figure 6 shows the minimum configuration of the transponder 20 according to an embodiment of the present disclosure. The transponder 20 is an FPGA installed on a satellite that performs wireless communication and detects radio waves unnecessary for the communication in the bandwidth used for communication, and as shown in Figure 6, comprises an IQ detection unit 2022a (an example of IQ detection means), an FFT processing unit 2022e (an example of FFT processing means), and a carrier regeneration unit 2022c (an example of carrier regeneration means).

[0064] The IQ detection unit 2022a detects the I signal and Q signal generated from the received signal. The FFT processing unit 2022e performs a Fast Fourier Transform on the signal before IQ decomposition detected by the IQ detection unit 2022a, and on at least one of the I signal and the Q signal. The carrier regeneration unit 2022c detects the carrier component from the I signal and Q signal detected by the IQ detection unit 2022a.

[0065] Figure 7 shows an example of the processing flow of the minimal transponder 20 according to the embodiments of this disclosure. Next, the processing by the minimal transponder 20 according to the embodiments of this disclosure will be described with reference to Figure 7.

[0066] The IQ detection unit 2022a detects the I signal and Q signal generated from the received signal (step S31). The FFT processing unit 2022e performs a Fast Fourier Transform on the signal before IQ decomposition detected by the IQ detection unit 2022a, and on at least one of the I signal and the Q signal (step S32). The carrier regeneration unit 2022c detects the carrier component from the I signal and the Q signal detected by the IQ detection unit 2022a (step S33).

[0067] The minimum configuration of the transponder 20 according to the embodiments of this disclosure has been described above. The transponder 20 can detect radio waves that are unnecessary for the communication in the bandwidth used for communication, thereby reducing the scale of hardware in the satellite that performs wireless communication.

[0068] In addition, the order of processing in the embodiments of this disclosure may be changed, as long as appropriate processing is performed.

[0069] While embodiments of this disclosure have been described, the communication system 1, transponder 20, and other control devices described above may have a computer system internally. The process described above is stored in program form on a computer-readable recording medium, and the process is performed when the computer reads and executes this program. A specific example of a computer is shown below.

[0070] Figure 8 is a schematic block diagram showing the configuration of a computer according to at least one embodiment. As shown in Figure 8, the computer 5 includes a CPU 6, main memory 7, storage 8, and interface 9. For example, the communication system 1, transponder 20, and other control devices described above are each implemented in the computer 5. The operation of each of the above-described processing units is stored in the storage 8 in the form of a program. The CPU 6 reads the program from the storage 8 and loads it into the main memory 7, and executes the above-described processing according to the program. The CPU 6 also allocates storage areas in the main memory 7 corresponding to each of the above-described storage units according to the program.

[0071] Examples of storage 8 include HDDs (Hard Disk Drives), SSDs (Solid State Drives), magnetic disks, magneto-optical disks, CD-ROMs (Compact Disc Read Only Memory), DVD-ROMs (Digital Versatile Disc Read Only Memory), and semiconductor memory. Storage 8 may be an internal medium directly connected to the bus of computer 5, or an external medium connected to computer 5 via interface 9 or a communication line. Furthermore, if this program is distributed to computer 5 via a communication line, computer 5, upon receiving the program, may expand it into main memory 7 and execute the above processing. In at least one embodiment, storage 8 is a tangible storage medium that is not temporary.

[0072] Furthermore, the above program may implement some of the functions described above. Moreover, the above program may be a file that can implement the above functions in combination with a program already recorded in the computer system, a so-called differential file (differential program).

[0073] While several embodiments of this disclosure have been described, these embodiments are illustrative and do not limit the scope of the invention. These embodiments may be modified in various ways, without departing from the spirit of the invention. [Explanation of symbols]

[0074] 1, 1a... Communication system 5. Computers 6..CPU 7. Main Memory 8. Storage 9. Interface 10. Satellite-mounted antenna 20...Transponder 30. Satellite-borne computers 40. FFT Processing Unit 201...Receiver System High-Frequency Section 201a···LNA 201b... Downconverter 202...Digital Signal Processing Unit 203...Transmission System High-Frequency Section 401...FFT Processing Unit 2021... A / D converter 2022...FPGA 2023...D / A Converter 2022a, 2022a1...IQ detection section 2022b, 2022b1...PN code synchronization section 2022c, 2022c1... Carrier Regeneration Department 2022d, 2022d1... Command demodulation unit 2022e, 2022e1...FFT processing unit 2022f, 2022f1... Modulation signal processing unit 2022g, 2022g1...IQ Modulation Unit

Claims

1. A transponder installed on a satellite that performs wireless communication, which detects radio waves in the bandwidth used for communication that are not needed for the communication, A receiving system high-frequency processing means that amplifies an analog received signal and converts the amplified received signal into an analog IF (Intermediate Frequency) signal, A / D (Analog to Digital) conversion means for converting the aforementioned analog IF signal to a digital IF signal, IQ detection means that decomposes a received signal into an I signal and a Q signal, detects the I signal and the Q signal, and outputs at least one of the signal before IQ decomposition, the I signal, and the Q signal, An FFT processing means configured with an FPGA (Field Programmable Gate Array), comprising: an FFT processing means that performs a Fast Fourier Transform on at least one of the signals before IQ decomposition detected by the IQ detection means, the I signal, and the Q signal; A carrier regeneration means for detecting carrier components from the I signal and the Q signal after dediffusion processing, Equipped with, The receiving system high-frequency processing means, the A / D conversion means, and the IQ detection means are, The process used in identifying the process and commands for performing the Fast Fourier Transform, transponder.

2. The FPGA is, The internal configuration is determined by a hardware description language described to execute the IQ detection means, the carrier regeneration means, and the FFT processing means. The transponder according to claim 1.

3. A CPU that executes a program described to perform the IQ detection means and the carrier regeneration means. The transponder according to claim 1, comprising:

4. ASIC configured to perform the IQ detection means and the carrier regeneration means, The transponder according to claim 1, comprising:

5. The aforementioned satellite is a satellite that performs wireless communication, The aforementioned IQ detection means is A signal is generated by canceling out the spreading code in the I signal and the Q signal. The carrier regeneration means is The carrier component is detected from the signal generated by the IQ detection means. A transponder according to any one of claims 1 to 4.

6. A transponder according to any one of claims 1 to 5, A satellite-borne computer executes a command identified based on the carrier components detected by the carrier regeneration means and analyzes the results of the fast Fourier transform performed by the FFT processing means. A communication system equipped with [the following features].

7. A transponder installed on a satellite performing wireless communication, which detects radio waves unnecessary for the communication in the bandwidth used for communication, and comprises a receiving system high-frequency processing means, an A / D (Analog to Digital) conversion means, an IQ detection means, an FFT processing means composed of an FPGA (Field Programmable Gate Array), and a carrier regeneration means, and is a processing method executed by the transponder, The aforementioned receiving system high-frequency processing means amplifies the analog received signal and converts the amplified received signal into an analog IF (Intermediate Frequency) signal. The A / D conversion means converts the analog IF signal into a digital IF signal, The IQ detection means detects the I signal and the Q signal by decomposing the received signal into an I signal and a Q signal, and outputs at least one of the signals before IQ decomposition, the I signal, and the Q signal. The FFT processing means performs a Fast Fourier Transform on at least one of the signals before IQ decomposition detected by the IQ detection means, the I signal, and the Q signal. The carrier regeneration means detects carrier components from the I signal and the Q signal after dediffusion processing, Includes, The receiving system high-frequency processing means, the A / D conversion means, and the IQ detection means are, The process used in identifying the process and commands for performing the Fast Fourier Transform, Processing method.

8. A program for determining the circuit configuration in an FPGA (Field Programmable Gate Array), which is programmable hardware that includes a receiving system high-frequency processing means, an A / D (Analog to Digital) conversion means, an IQ detection means, an FFT processing means composed of an FPGA (Field Programmable Gate Array), and a carrier regeneration means, which detects radio waves unnecessary for the communication in the bandwidth used for communication, and is provided on a transponder installed on a satellite that performs wireless communication. The aforementioned receiving system high-frequency processing means amplifies the analog received signal and converts the amplified received signal into an analog IF (Intermediate Frequency) signal. The A / D conversion means converts the analog IF signal into a digital IF signal, The IQ detection means detects the I signal and the Q signal by decomposing the received signal into an I signal and a Q signal, and outputs at least one of the signals before IQ decomposition, the I signal, and the Q signal. The FFT processing means performs a Fast Fourier Transform on at least one of the signals before IQ decomposition detected by the IQ detection means, the I signal, and the Q signal. The carrier regeneration means detects carrier components from the I signal and the Q signal after dediffusion processing, A circuit to perform this is configured in the FPGA. The receiving system high-frequency processing means, the A / D conversion means, and the IQ detection means are, The process used in identifying the process and commands for performing the Fast Fourier Transform, program.

9. A transponder installed on a satellite performing wireless communication, which detects radio waves unnecessary for the communication in the bandwidth used for communication, is configured as an FPGA (Field Programmable Gate Array) and has FFT processing means that performs a Fast Fourier Transform on at least one of the detected signal before IQ decomposition, the I signal and the Q signal, and is equipped with a computer including receiving system high-frequency processing means, A / D (Analog to Digital) conversion means, IQ detection means and carrier regeneration means, The aforementioned receiving system high-frequency processing means amplifies the analog received signal and converts the amplified received signal into an analog IF (Intermediate Frequency) signal. The A / D conversion means converts the analog IF signal into a digital IF signal, The IQ detection means detects the I signal and the Q signal by decomposing the received signal into the I signal and the Q signal, and outputs at least one of the signals before IQ decomposition, the I signal, and the Q signal. The carrier regeneration means detects carrier components from the I signal and the Q signal after dediffusion processing, Make it run, The receiving system high-frequency processing means, the A / D conversion means, and the IQ detection means are, The process used in identifying the process and commands for performing the Fast Fourier Transform, program.

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