Digital full broadband direct forwarding search and rescue radar transponder system

Abstract

The present invention proposes a digital full-wideband direct forwarding search and rescue radar transponder system, which proposes a new search and rescue radar transponder (SART) system architecture and a corresponding new coding and reading scheme. The system of the present invention adopts a direct forwarding system architecture, which combines digital broadband DRFM real-time forwarding technology and discontinuous point coding response architecture. The transmitting and receiving antennas work independently and simultaneously, and all radar interrogation signals within the working frequency band are directly encoded and forwarded indiscriminately, retaining the complete waveform information while realizing the encoding of the response information. The system of the present invention can be equivalent to a target with special target characteristics. After the radar signal within the working frequency band is irradiated to the target, an echo signal with fixed coding modulation characteristics will be generated.

Description

Technical Field

[0001] The invention belongs to the technical field of ship navigation radio, and in particular relates to a digital full-bandwidth direct forwarding search and rescue radar transponder system. Background Art

[0002] The Search and Rescue Radar Transponder (SART) is mainly used on ships and is an auxiliary device for search and rescue missions at the scene of distress at sea. When the Search and Rescue Radar Transponder (SART) is turned on, as long as there is a search and rescue radar interrogation signal, the Search and Rescue Radar Transponder (SART) will generate a coded response signal with a specific meaning, and a series of bright spots will be displayed on the search and rescue radar screen, thereby locating the person to be rescued, making it easier for the search and rescue ship to arrive at the scene of distress in time for rescue.

[0003] The existing search and rescue radar transponder (SART) is mainly implemented in a sweep frequency mode. The transmitter works under the control of the sawtooth pulse of the scanner and the square wave of the receiver. The transmission frequency range is 9200-9500MHz, which makes it easy for the search and rescue radar to receive the reply signal.

[0004] The working principle of the swept-frequency search and rescue radar transponder (SART) is as follows: when a ship in distress is waiting for rescue, the search and rescue radar transponder (SART) is turned on to receive microwave signals within the range of 9200MHz-9500MHz. Every time a search and rescue radar inquiry signal is received, a 100us square wave is generated, and the square wave controls the sweeper, which controls the transmitter to continuously transmit 12 sweep pulse signals with frequencies from 9200MHz to 9500MHz and from 9500MHz to 9200MHz. The forward single sweep time is 7.5±1us, and the reverse single sweep time is 0.4±0.1us. A series of bright spots will be displayed on the display screen of the search and rescue radar, and the display interval between two bright spots is about 8us.

[0005] The current SART system has the following deficiencies:

[0006] 1) It is sensitive to radar transmission waveforms and signal processing systems, and is only applicable to narrowband, simple modulation radar waveforms, and cannot adapt to new system broadband, complex modulation waveforms;

[0007] 2) The antenna uses a time-division multiplexing system for transmission and reception. It cannot respond to radar inquiries during the transmission period, which may result in the loss of responses to some search and rescue radar signals. Summary of the invention

[0008] The purpose of the present invention is to overcome the defects of the prior art and to solve the problem that the current search and rescue radar transponder (SART) cannot respond to the new system radar with broadband and complex modulation waveform. The present invention provides a digital full-bandwidth direct forwarding search and rescue radar transponder system.

[0009] The traditional search and rescue radar transponder (SART) system adopts a frequency sweeping-generation system architecture, which uses the same antenna for both transmission and reception. Since the response waveform of the traditional search and rescue radar transponder (SART) is a simple frequency sweeping signal, and the new solid-state search and rescue radar uses a large bandwidth and complex modulation waveform, the response signal form does not match the signal form emitted by the new search and rescue radar, resulting in the search and rescue radar being unable to receive the response signal.

[0010] In order to achieve the response to the new system radar, the present invention proposes a new search and rescue radar transponder (SART) system architecture and a new coding and reading scheme. The system of the present invention uses digital direct forwarding as the system architecture, and adopts digital broadband DRFM real-time forwarding technology. The transmitting and receiving antennas are independent and work simultaneously. It can directly and indiscriminately encode and forward all radar interrogation signals within the working frequency band, retaining the complete waveform information while realizing the encoding of the response information. The system of the present invention can be equivalent to a target with special characteristics. The radar signal within the working frequency band is irradiated onto the target to generate an echo signal with fixed coding modulation characteristics.

[0011] The core of the system of the present invention is to adopt the coding modulation method. Every time the standard search and rescue radar transponder (SART) receives a search and rescue radar trigger signal, it generates a 100us square wave. The square wave signal controls the frequency sweeper, and the frequency sweeper controls the transmitter to continuously transmit 12 sweep pulse signals with frequencies from 9200MHz to 9500MHz and from 9500MHz to 9200MHz. The forward single sweep time is 7.5±1us, and the reverse single sweep time is 0.4±0.1us. The display screen of the search and rescue radar displays a series of bright spots in the radial direction that are clearly different from other objects, and the total length is about 8us*150m / us*12=14.4km. In order to achieve the response to the new radar system, the system of the present invention adopts a point coding response architecture to replace the current coding effect. The coding principle of the coding architecture is: 1) Each "dot" represents the basic symbol unit in the code, with a length of about 8us; 2) 12 "dots" are superimposed after delaying step by step to form a string of echo signals with 12 bright spots, and the delay of each level is 8us; 3) The distance occupied by each echo "dot" displayed on the radar depends on the radar resolution. According to the above principles, the coding is carried out, and the received code can be easily identified on the search and rescue radar display screen based on the number of echo points and the equal spacing between echo points.

[0012] The present invention specifically adopts the following technical solutions:

[0013] A digital full-wideband direct forwarding search and rescue radar transponder system, characterized by: adopting digital broadband DRFM real-time forwarding technology and discontinuous point coding response architecture; the transmitting and receiving antennas work independently and simultaneously, and directly forward all radar interrogation signals within the working frequency band without distinction;

[0014] The coding principles adopted are: 1) Each "dot" represents the basic symbol unit in the code, with a length of 8us; 2) The 12 "dots" are delayed step by step and then superimposed to form a string of echo signals with 12 bright spots, with a delay of 8us at each level; 3) The distance occupied by each echo "dot" displayed on the radar depends on the radar resolution.

[0015] The delay of 8us refers to a theoretical value, and a certain deviation is allowed in actual engineering implementation. As long as it is guaranteed to be around 8us, it is also within the protection scope of the present invention.

[0016] Furthermore, the coded modulation is implemented by two parts: a tap delay device and a superposition module;

[0017] The tap delayer adopts a multi-stage delay tap superposition architecture, the delay modules are connected end to end to form a delay chain, the delay value of each stage of the delay module is the same and fixed, the fixed delay value is 8us, and the tap data is led from the tap delayer input and the output of each stage of the delay module to the superposition module;

[0018] The superposition module superimposes all input tap data into a coded modulation waveform output.

[0019] Furthermore, the coded modulation is used to realize a string of bright spots displayed as “dot-dot-dot-dot-dot-dot-dot-dot-dot-dot-dot-dot” on the search and rescue radar screen, and these bright spots correspond one to one with the coding setting value “111111111111”, each “dot” represents an 8us delay, and the coding duration is 8us*12=96us.

[0020] Furthermore, the complete system includes: an antenna system consisting of a receiving antenna and a transmitting antenna, a radio frequency transceiver module consisting of a radio frequency receiving link and a radio frequency transmitting link, and a baseband processing module including an ADC acquisition module, an FPGA processing module and a DAC playback module;

[0021] The receiving antenna is used to receive radar transmission signals within the working frequency band from space, and the transmitting antenna is used to radiate system response signals into space;

[0022] The RF transceiver module consists of an RF receiving link and an RF transmitting link. The RF transceiver link shares the local oscillator module, covering the 300MHz working bandwidth of the entire search and rescue radar transponder (SART). The RF receiving link is used to convert the RF signal output by the receiving antenna into an intermediate frequency signal and output it to the ADC acquisition module of the baseband processing module; the RF transmitting link is used to convert the intermediate frequency signal output by the DAC playback module of the baseband processing module into an RF signal and output it to the transmitting antenna; both the RF receiving link and the RF transmitting link include: RF devices such as filters, amplifiers and mixers.

[0023] The baseband processing module consists of an ADC acquisition module, an FPGA processing module and a DAC playback module.

[0024] The ADC acquisition module converts the intermediate frequency analog signal output by the RF receiver into a digital signal and sends it to the FPGA processing module; the DAC playback module converts the digital signal output by the FPGA processing module into an analog signal and sends it to the intermediate frequency analog input interface of the RF transmitter.

[0025] The sampling rate settings of the ADC acquisition module and the DAC playback module must ensure that the signals within the 300MHz bandwidth of the entire search and rescue radar transponder (SART) can be acquired in the full frequency band.

[0026] The FPGA processing module is used to implement orthogonal down-conversion processing, envelope detection, coding modulation and orthogonal up-conversion processing of ADC collected data.

[0027] Furthermore, it also includes: an antenna cover, which is used to protect each component module and prevent the environment from affecting and interfering with the working state of each component module.

[0028] Furthermore, the operating frequency band range of the antenna system covers the 300MHz bandwidth operating range of the search and rescue radar transponder, and the isolation between the transmitting and receiving antennas is much greater than the total gain of the system; the operating frequency band range of the RF transceiver link covers the 300MHz bandwidth operating range of the search and rescue radar transponder of 9.2GHz-9.5GHz, and the RF receiving link and the RF transmitting link both include: filters, amplifiers and mixers; the sampling rate settings of the ADC acquisition module and the DAC playback module need to ensure that the signals within the 300MHz bandwidth range of the search and rescue radar transponder can be fully acquired.

[0029] Furthermore, the working method comprises the following steps:

[0030] Step S1: Turn on the device, power on and initialize it, and enter the standby state;

[0031] Step S2: The receiving antenna receives the radar transmission signal within the working frequency band from space;

[0032] Step S3: The RF receiving link filters, amplifies, mixes, filters, and amplifies the RF signal output by the receiving antenna, and then outputs an intermediate frequency signal;

[0033] Step S4: the ADC acquisition module of the baseband processing module performs analog-to-digital conversion on the intermediate frequency analog signal output by the RF receiving link, converts it into a digital signal and outputs it;

[0034] Step S5: The FPGA processing module of the baseband processing module receives the digital signal output by the ADC acquisition module and performs DDC processing on it, and moves the received signal to the baseband;

[0035] Step S6: The coding and modulation module in the FPGA processing module receives the baseband signal output by the DDC processing module and performs coding and modulation processing on it;

[0036] Step S7: The DUC module in the FPGA processing module receives the output of the coding modulation module and performs up-conversion processing on it, and outputs an intermediate frequency digital signal after processing;

[0037] Step S8: the DAC playback module of the baseband processing module performs digital-to-analog conversion on the intermediate frequency digital signal output by the DUC module in the FPGA processing module, converts it into an analog intermediate frequency signal, and then outputs it;

[0038] Step S9: The RF transmission link filters, amplifies, mixes, filters, and amplifies the intermediate frequency analog signal output by the baseband processing module DAC playback module, and then outputs the RF signal;

[0039] Step S10: The transmitting antenna radiates the radio frequency signal output by the radio frequency transmission link into space.

[0040] Compared with the prior art, the transmitting and receiving antennas of the present invention work independently and simultaneously, and can realize indiscriminate coding and forwarding of all search and rescue radar interrogation signals. The beneficial effects of the present invention and its preferred solution include:

[0041] 1) It is insensitive to radar transmission waveform and signal processing system. It can respond to new radar signals with complex modulation waveforms while being compatible with traditional radar signals, making it possible to apply new technologies and new systems to ship search and rescue radar systems;

[0042] 2) Ability to simultaneously and reliably respond to all received radar interrogation signals, even if multiple radar interrogation signals overlap in the time or frequency domain;

[0043] 3) It has smaller system delay, that is, it has higher distance accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments:

[0045] Figure 1 A block diagram of the system composition provided by an embodiment of the present invention;

[0046] Figure 2 This is a block diagram of a coding and modulation module implementation according to an embodiment of the present invention;

[0047] Figure 3 The following is a coding mapping relationship table according to an embodiment of the present invention. DETAILED DESCRIPTION

[0048] In order to make the features and advantages of this patent more obvious and easy to understand, the following embodiments are specifically described in detail as follows:

[0049] The technical solution of the present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0050] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those within the scope of this description. Therefore, the protection scope of the present invention is not limited to the specific embodiments disclosed below.

[0051] like Figure 1 As shown, the digital full-bandwidth direct forwarding search and rescue radar transponder system provided in this embodiment includes the following parts:

[0052] (1) Receiving antenna, (2) RF receiving link, (3) Baseband processing module, (4) RF transmitting link, (5) Transmitting antenna.

[0053] in:

[0054] (1) Receiving antenna, used to receive radar transmission signals within the working frequency band from space;

[0055] (2) RF receiving link, which is used to filter, amplify, mix, filter, and amplify the RF signal output by the receiving antenna and then output the intermediate frequency signal;

[0056] (3) Baseband processing module, used to perform ADC acquisition, digital down-conversion, coding modulation, digital up-conversion and DAC playback on the intermediate frequency analog signal output by the RF receiving link;

[0057] (4) RF transmission link, used to filter, amplify, mix, filter, and amplify the intermediate frequency analog signal output by the baseband processing module DAC playback module and then output the RF signal;

[0058] (5) Transmitting antenna, used to radiate the RF signal output by the RF transmission link into space.

[0059] In this embodiment, the connection relationship between the above components is: from (1) to (5), the output of the previous module is connected to the input of the next module in sequence, thereby forming the basic components of the system.

[0060] The following describes each component of the system of this embodiment.

[0061] Antenna system: The antenna system consists of a receiving antenna and a transmitting antenna. The working frequency range of the antenna covers the 300MHz bandwidth working range of the entire search and rescue radar transponder (SART) (X band: 9.2G~9.5G). The receiving antenna is used to receive radar transmission signals within the working frequency range from space, and the transmitting antenna is used to radiate the system response signal to space. Since the transmitting and receiving antennas need to work at the same time, in order to avoid self-excitation of the system, the isolation between the transmitting and receiving antennas must be much greater than the total gain of the system. The system gain is proportional to the response distance. In order to increase the response distance, the design of high-isolation transmitting and receiving antennas is crucial to this system. There are two feasible ways to design high-isolation antennas: 1) Optimize the parameters and layout of the transmitting and receiving antennas themselves 2) Add a cancellation device, or combine the above two ways. The transmitting and receiving antennas need to be placed up and down, both in a basically vertical state, and the farther apart, the better. For compactness, a radio signal isolation plate can be added between the transmitting and receiving antennas in the structural design. The isolation plate is made of metal and other materials that have an isolation or shielding effect on radio signals. The transmitting and receiving antennas are approximately in a vertical line or slightly staggered. The isolation plate is generally circular, square, etc. The center of the isolation plate is approximately on the line connecting the two antennas and close to the middle position between the two antennas. It is approximately horizontal and perpendicular to the antenna to avoid self-excitation of the system, thereby increasing the transmission power and achieving the effect of increasing the response distance.

[0062] RF transceiver module: The RF transceiver module consists of an RF receiving link and an RF transmitting link. The operating frequency band of the RF transceiver link covers the 300MHz bandwidth operating range of the entire search and rescue radar transponder (SART) (X-band: 9.2G~9.5G). Both the RF receiving link and the RF transmitting link are composed of core components such as filters, amplifiers, and mixers, and the RF transceiver link shares the local oscillator module. The RF receiving link is used to convert the RF signal output by the receiving antenna into an intermediate frequency signal and output it to the ADC acquisition module of the baseband processing module. The RF transmitting link is used to convert the intermediate frequency signal output by the DAC playback module of the baseband processing module into an RF signal and output it to the transmitting antenna.

[0063] Baseband processing module: The baseband processing module is mainly composed of an ADC acquisition module, an FPGA processing module and a DAC playback module. The ADC acquisition module converts the intermediate frequency analog signal output by the RF receiver into a digital signal and sends it to the FPGA processing module. The DAC playback module converts the digital signal output by the FPGA processing module into an analog signal and sends it to the intermediate frequency analog input interface of the RF transmitter. The sampling rate setting of the ADC acquisition module and the DAC playback module must ensure that the signals within the 300MHz bandwidth range of the entire search and rescue radar transponder (SART) can be acquired in the full frequency band. The FPGA processing module is the core module of the system of the present invention, which mainly realizes the orthogonal down-conversion processing, envelope detection, coding modulation and orthogonal up-conversion processing of the ADC acquisition data.

[0064] like Figure 2 to Figure 3 As shown, coding modulation is the core processing link of the system of this embodiment, which consists of two parts: a tap delay and a superposition module. The tap delay is implemented by a multi-stage delayed tap superposition architecture. The delay modules are connected end to end to form a delay chain, and the delay value of each stage of the delay module is the same and can be set. The tap data is led from the input of the tap delay and the output of each stage of the delay module to the superposition module; the superposition module superimposes all the input tap data into one coded modulation waveform output. The fixed value of the coding setting is 111111111111. Each bit of the coding setting value is called a basic symbol unit. The basic principle of mapping the coding setting value to the display effect of "dot-dot-dot-dot-dot-dot-dot-dot-dot-dot-dot-dot" is: "dot" is represented by 1, and the delay represented by "dot" is about 8us. The total coding time is about 8us*12=96us.

[0065] Figure 3 Among them: A: basic symbol length (delay length corresponding to a "point"), which is consistent with the delay value of each level of delay unit; B: radar display length, which is consistent with radar resolution; C: device inherent delay. Among them, the input waveform pulse width has no direct connection with A.

[0066] Radome: The radome is used to protect other parts of the system of the present invention and prevent the environment from affecting and interfering with the working state of other parts. At the same time, the design of the radome has a certain influence on the isolation of the transmitting and receiving antennas of the system of the present invention. The design of the radome and the design of the transmitting and receiving antennas should be considered comprehensively.

[0067] Based on the above system and design principles, this embodiment provides a more specific design and working method under the system architecture:

[0068] 1) Power on the system and initialize it;

[0069] 2) Send the coding configuration value: 12'b1111_1111_1111 and the tap delay delay value: 2000 (corresponding to the basic symbol unit length: 2000*4ns=8us) to the coding modulation module of the baseband processing module;

[0070] 3) The receiving antenna (X: 9.2~9.5G, omnidirectional, horizontal polarization, elevation angle 22°, gain 6dBi, isolation between transmitting and receiving antennas 85dB) receives radar transmission signals within the working frequency band from space;

[0071] 4) The RF receiving link (input: 9.2~9.5GHz, output: 600~900MHz, gain: 30dB) filters, amplifies, mixes, filters, amplifies the RF signal output by the receiving antenna, and then outputs the intermediate frequency signal;

[0072] 5) The ADC acquisition module (sampling rate 1Gbps) of the baseband processing module performs analog-to-digital conversion of the intermediate frequency analog signal output by the RF receiving link, converts it into a digital signal (4 channels in parallel @ 250MHz) and outputs it;

[0073] 6) The FPGA processing module of the baseband processing module (FPGA model: xc7v325t-ffg900) receives the digital signal output by the ADC acquisition module and performs DDC processing on it (local oscillator frequency 750MHz, filter bandwidth 300MHz, 4 samplings), and moves the received signal to the baseband (1 signal, sampling rate 250Mbps);

[0074] 7) The coding and modulation module in the FPGA processing module receives the baseband signal output by the DDC processing module and performs coding and modulation processing on it;

[0075] 8) The DUC module (local oscillator frequency 750MHz, filter bandwidth 300MHz, 4 interpolation) in the FPGA processing module receives the output of the coding modulation module and performs up-conversion processing on it, and then outputs the intermediate frequency digital signal (4 parallel channels @250MHz) after processing;

[0076] 9) The DAC playback module of the baseband processing module performs digital-to-analog conversion on the intermediate frequency digital signal output by the DUC module in the FPGA processing module, converts it into an analog intermediate frequency signal and then outputs it (1 channel, 600-900MHz);

[0077] 10) The RF transmission link (input: 600-900MHz, output: 9.2-9.5GHz, gain: 50dB) filters, amplifies, mixes, filters, amplifies the intermediate frequency analog signal output by the DAC playback module in the baseband processing module, and then outputs the RF signal;

[0078] 11) The transmitting antenna (X: 9.2~9.5G, omnidirectional, horizontal polarization, elevation angle 22°, gain 6dBi, isolation between transmitting and receiving antennas 85dB) radiates the RF signal output by the RF transmission link into space.

[0079] The above is only a preferred embodiment of the present invention, and does not limit the present invention in other forms. Any technician familiar with the profession may use the above disclosed technical content to change or modify it into an equivalent embodiment with equivalent changes. However, any simple modification, equivalent change and modification made to the above embodiment according to the technical essence of the present invention without departing from the technical solution of the present invention still belongs to the protection scope of the technical solution of the present invention.

[0080] Obviously, the above embodiments of the present invention are only examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A digital full broadband direct forwarding search and rescue radar transponder system, characterized in that: Adopt digital broadband DRFM real-time forwarding technology and discontinuous point coding response architecture; the transmitting and receiving antennas work independently and simultaneously, directly and indiscriminately forwarding all radar interrogation signals within the working frequency band; The coding principle adopted is: 1) Each "dot" represents the basic symbol unit in the coding, with a length of 8us; 2) The 12 "dots" are delayed step by step and then superimposed to form a string of echo signals with 12 bright spots, with a delay of 8us at each level; 3) The distance occupied by each echo "dot" displayed on the radar depends on the radar resolution; The coded modulation is implemented by two parts: the tap delay and the superposition module; The tap delayer adopts a multi-stage delay tap superposition architecture, the delay modules are connected end to end to form a delay chain, the delay value of each stage of the delay module is the same and fixed, the fixed delay value is 8us, and the tap data is led from the tap delayer input and the output of each stage of the delay module to the superposition module; The superposition module superimposes all input tap data into a coded modulation waveform output; Through the described coding modulation, a series of bright spots are displayed on the search and rescue radar screen as "dot-dot-dot-dot-dot-dot-dot-dot-dot-dot-dot-dot", and these bright spots correspond one to one with the coding setting value "111111111111", each "dot" represents an 8us delay, and the coding duration is 8us*12=96us.

2. The digital full-broadband direct forwarding search and rescue radar transponder system according to claim 1 is characterized in that: include: An antenna system consisting of a receiving antenna and a transmitting antenna, a radio frequency transceiver module consisting of a radio frequency receiving link and a radio frequency transmitting link, and a baseband processing module including an ADC acquisition module, an FPGA processing module and a DAC playback module; The receiving antenna is used to receive radar transmission signals within the working frequency band from space, and the transmitting antenna is used to radiate system response signals into space; The RF transceiver link shares the local oscillator module; The RF receiving link is used to convert the RF signal output by the receiving antenna into an intermediate frequency signal and output it to the ADC acquisition module of the baseband processing module; The RF transmission link is used to convert the intermediate frequency signal output by the DAC playback module of the baseband processing module into a RF signal and output it to the transmitting antenna; The ADC acquisition module converts the intermediate frequency analog signal output by the RF receiver into a digital signal and sends it to the FPGA processing module; the DAC playback module converts the digital signal output by the FPGA processing module into an analog signal and sends it to the intermediate frequency analog input interface of the RF transmitter; the FPGA processing module is used to realize orthogonal down-conversion processing, envelope detection, coding modulation and orthogonal up-conversion processing of ADC acquisition data.

3. The digital full-broadband direct forwarding search and rescue radar transponder system according to claim 2 is characterized in that: Also includes: The antenna cover is used to protect each component module and prevent the environment from affecting and interfering with the working status of each component module.

4. The digital full-broadband direct forwarding search and rescue radar transponder system according to claim 2, characterized in that: The working frequency band range of the antenna system covers the 300MHz bandwidth working range of the search and rescue radar transponder, and the isolation between the transmitting and receiving antennas is much greater than the total gain of the system; the working frequency band range of the RF transceiver link covers the 300MHz bandwidth working range of the search and rescue radar transponder of 9.2GHz-9.5GHz, and the RF receiving link and the RF transmitting link both include: filters, amplifiers and mixers; the sampling rate settings of the ADC acquisition module and the DAC playback module must ensure that the signals within the 300MHz bandwidth range of the search and rescue radar transponder can be fully acquired.

5. The digital full-broadband direct forwarding search and rescue radar transponder system according to claim 2, characterized in that: Its working method includes the following steps: Step S1: Turn on the device, power on and initialize it, and enter the standby state; Step S2: The receiving antenna receives the radar transmission signal within the working frequency band from space; Step S3: The RF receiving link filters, amplifies, mixes, filters, and amplifies the RF signal output by the receiving antenna, and then outputs an intermediate frequency signal; Step S4: the ADC acquisition module of the baseband processing module performs analog-to-digital conversion on the intermediate frequency analog signal output by the RF receiving link, converts it into a digital signal and outputs it; Step S5: The FPGA processing module of the baseband processing module receives the digital signal output by the ADC acquisition module and performs DDC processing on it, and moves the received signal to the baseband; Step S6: The coding and modulation module in the FPGA processing module receives the baseband signal output by the DDC processing module and performs coding and modulation processing on it; Step S7: The DUC module in the FPGA processing module receives the output of the coding modulation module and performs up-conversion processing on it, and outputs an intermediate frequency digital signal after processing; Step S8: the DAC playback module of the baseband processing module performs digital-to-analog conversion on the intermediate frequency digital signal output by the DUC module in the FPGA processing module, converts it into an analog intermediate frequency signal, and then outputs it; Step S9: The RF transmission link filters, amplifies, mixes, filters, and amplifies the intermediate frequency analog signal output by the baseband processing module DAC playback module, and then outputs the RF signal; Step S10: The transmitting antenna radiates the radio frequency signal output by the radio frequency transmission link into space.

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