WO2023168734A1 - 数字全宽带直接转发式雷达应答器系统及其工作方法 - Google Patents

数字全宽带直接转发式雷达应答器系统及其工作方法 Download PDF

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Publication number
WO2023168734A1
WO2023168734A1 PCT/CN2022/081110 CN2022081110W WO2023168734A1 WO 2023168734 A1 WO2023168734 A1 WO 2023168734A1 CN 2022081110 W CN2022081110 W CN 2022081110W WO 2023168734 A1 WO2023168734 A1 WO 2023168734A1
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module
radio frequency
radar
processing module
morse code
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PCT/CN2022/081110
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English (en)
French (fr)
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李锐
李玉东
曾群超
刘春海
刘华松
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上海哪佤科技有限公司
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Priority to EP22868453.6A priority Critical patent/EP4270056A4/en
Priority to US18/109,276 priority patent/US20230283356A1/en
Publication of WO2023168734A1 publication Critical patent/WO2023168734A1/zh

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
    • G01S7/02—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S13/00
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S13/00—Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
    • G01S13/74—Systems using reradiation of radio waves, e.g. secondary radar systems; Analogous systems
    • G01S13/75—Systems using reradiation of radio waves, e.g. secondary radar systems; Analogous systems using transponders powered from received waves, e.g. using passive transponders, or using passive reflectors

Definitions

  • the invention belongs to the technical field of radio navigation, and in particular relates to a digital full-bandwidth direct forwarding radar transponder system and its working method.
  • Radar transponders are generally navigation aids used to identify buoys, lighthouses, ports, coasts and other objects of navigational significance.
  • the radar transponder When a radar interrogation signal is detected, the radar transponder generates a Morse coded response signal that represents a specific meaning.
  • Frequency-agile radar transponders contain additional circuitry to determine the frequency of each interrogation pulse received and rapidly tune the response signal frequency to match it.
  • the current mainstream frequency-agile radar transponder is an analog system transponder. Its working principle is: through detection, main lobe detection and frequency measurement circuits, the starting frequency and pulse width of the required response waveform are obtained. After obtaining the starting frequency, the The controlled oscillator generates a point frequency pulse response signal. The response waveform generated by the voltage controlled oscillator is output after passing through the gate switch. The gating time of the gate switch is controlled by the Morse code value.
  • the antenna adopts a time-division multiplexing system for transmitting and receiving. It cannot respond to radar interrogation during the signal transmission period. In radar-intensive scenes such as ports, the processing capacity will be saturated, thereby losing effective response to surrounding radar interrogation signals;
  • the frequency measurement generation formula uses the frequency measurement generation formula to calculate the frequency, amplitude and other parameters of the radar interrogation signal to be measured and identified before responding. When there are radars emitting the same waveform in the surroundings, it is easy to cause misidentification.
  • the purpose of the present invention is to provide a digital full-bandwidth direct forwarding radar transponder system and its operation. method.
  • the traditional radar transponder system adopts a frequency measurement-generative architecture.
  • the transmitter and receiver share the same antenna.
  • a point frequency pulse response signal is generated according to the measured frequency parameters.
  • the generated response waveform is output after passing through the gate switch, and the gating time of the gate switch is controlled by the Morse code value. Since the response waveform of traditional radar transponders is a simple point frequency pulse signal and loses most of the waveform parameter information, traditional radar transponders cannot respond to new system radar waveforms with large bandwidth and complex modulation waveforms.
  • the system of the present invention proposes a brand-new radar transponder system architecture and a corresponding new Morse code reading scheme.
  • the system of the present invention adopts a direct forwarding system architecture, which combines digital broadband DRFM real-time forwarding technology and a point-replacement-line coding response architecture.
  • the transmitting and receiving antennas work independently and simultaneously, and directly encode and forward all radar interrogation signals within the working frequency band without distinction. While retaining the complete waveform information, Morse coding of the response information is achieved.
  • the system of the present invention can be equivalent to a target with special target characteristics. After the radar signal in the working frequency band is irradiated to the target, an echo signal with specified Moss code modulation characteristics will be generated.
  • One of the cores of the system of the present invention also includes the realization of Morse code modulation and the Morse code reading method.
  • Standard Morse code is constructed from three basic symbols: “dot”, “space” and “dash”.
  • "Dot” and “dash” are solid lines. The lengths of "dot” and “space” are equal.
  • “Dash” is “dot” or “dash”. Three times the length of "empty”.
  • the Morse code points and dashes responded by traditional radar transponders are displayed as radial solid lines on the radar, and their lengths meet the standard Morse coding rules.
  • the system of the present invention adopts a Moss coding response architecture that uses points instead of lines to replace the current Moss coding effect.
  • the coding principles of this coding architecture are: 1) Several echo points replace Moss The "dot" in the code, each echo point occupies a basic symbol unit; 2) The “dash” in the Morse code is replaced by echo points three times as many as the "dot", occupying three times as many basic symbol units as the "dot” symbol unit; 3) "empty” in Morse code occupies the same number of basic symbol units as "point”; 4) the distance of each echo point displayed on the radar depends on the radar resolution and is no longer equal to one basic symbol unit.
  • identifying Morse codes no longer relies on the absolute distance proportional relationship between "point", "empty” and “dash”, but mainly relies on the relationship between the number of echo points and the distance between starting points. As long as the basic symbol unit is larger than the minimum resolution of the radar, The distance unit can easily identify the received Morse code.
  • a digital full-bandwidth direct forwarding radar transponder system which is characterized in that it includes: an antenna system composed of a receiving antenna and a transmitting antenna, a radio frequency transceiver module composed of a radio frequency receiving link and a radio frequency transmitting link, and includes an ADC acquisition module, FPGA processing module and baseband processing module of 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 to space;
  • the radio frequency transceiver link shares a local oscillator module; the radio frequency receiving link is used to convert the radio frequency 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 radio frequency transmitting link is used to convert the baseband processing module The intermediate frequency signal output by the DAC playback module is converted into a radio frequency signal and output to the transmitting antenna;
  • the ADC acquisition module converts the intermediate frequency analog signal output by the radio frequency 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 signal of the radio frequency transmitter.
  • Analog input interface; the FPGA processing module is used to implement orthogonal down-conversion processing, envelope detection, Morse code modulation and orthogonal up-conversion processing of ADC collected data.
  • the Moss code modulation is implemented by three parts: a tap delayer, a coding switch module and a 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 delay module is the same and adjustable; the tap data is derived from the input of the tap delayer and the output of each stage delay module to the encoding. switch module;
  • the coding switch module is a switch array, and each tap data corresponds to an on-off switch.
  • the on-off of the switch is controlled by the Morse code setting value; the Morse code setting value is based on the Morse code symbol by searching the Morse code mapping relationship.
  • the table is obtained; the encoding switch module outputs the gated tap data to the superposition module to participate in superposition;
  • the superposition module superimposes all the input tap data into one coded modulation waveform output.
  • the Morse code mapping relationship table maps the "dot-dash-empty" representation method corresponding to the Morse symbol into the Morse code setting value; the basic principle of mapping is that "dot” or “dash” is represented by 1, “Empty” is represented by 0 between “dot-dot”, “dot-dash”, “dash-dot”, and “dash-dash”.
  • the number of bits occupied by "dot” and “empty” is the same, and the number of bits occupied by "dash” is the same.
  • the number of bits occupied is 3 times the number of bits occupied by "dot” or "empty”. It occupies the maximum length of data corresponding to the Morse coding setting value under the premise of satisfying the relative relationship between "dot", “dash” and "empty”.
  • the operating frequency range of the antenna system covers the 200MHz bandwidth operating range of the entire radar transponder, and the isolation between the transceiver antennas is greater than the total gain of the system; the operating frequency range of the radio frequency transceiver link covers the 200MHz bandwidth of the entire radar transponder.
  • Bandwidth working range, the radio frequency receiving link and the radio frequency transmitting link include: filters, amplifiers and mixers; the sampling rate settings of the ADC acquisition module and DAC playback module need to ensure that the entire radar transponder can The signals within the 200MHz bandwidth range are collected in the whole frequency band.
  • a radome is included for protecting each component module and preventing environmental influence and interference on the working status of each component module.
  • Step S1 Power on and initialize
  • Step S2 The receiving antenna receives the radar transmission signal within the working frequency band from space;
  • Step S3 The radio frequency receiving link filters, amplifies, mixes, filters, and amplifies the radio frequency signal output by the receiving antenna and outputs an intermediate frequency signal;
  • Step S4 The ADC acquisition module of the baseband processing module converts the intermediate frequency analog signal output from the radio frequency receiving link 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 Morse code modulation module in the FPGA processing module receives the baseband signal output from the DDC processing module and performs Morse code modulation processing on it;
  • Step S7 The DUC module in the FPGA processing module receives the output of the Moss code 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 outputs it;
  • Step S9 The radio frequency 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 radio frequency signal;
  • Step S10 The transmitting antenna radiates the radio frequency signal output by the radio frequency transmission link into space.
  • the present invention and its preferred solution transmit and receive antennas work independently and simultaneously, without the need to detect and identify the parameter characteristics of the input signal, and achieve indiscriminate coding and forwarding of all radar interrogation signals. Its beneficial effects include:
  • Figure 1 is a system block diagram provided by an embodiment of the present invention.
  • FIG. 2 is an implementation block diagram of a Moss coding modulation module according to an embodiment of the present invention
  • FIG. 3 is a schematic diagram of the Moss coding modulation principle according to an embodiment of the present invention.
  • Figure 4 is a Morse code mapping relationship table according to an embodiment of the present invention.
  • the digital full-bandwidth direct forwarding radar transponder system includes the following parts:
  • the receiving antenna is used to receive radar transmission signals within the working frequency band from space;
  • Radio frequency receiving link used to filter, amplify, mix, filter, and amplify the radio frequency signal output by the receiving antenna and then output an intermediate frequency signal
  • Baseband processing module used for ADC acquisition, digital down-conversion, Morse code modulation, digital up-conversion and DAC playback of the intermediate-frequency analog signals output from the radio frequency receiving link;
  • Radio frequency 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 radio frequency signal;
  • 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, thus forming the basic composition of the system.
  • the antenna system consists of a receiving antenna and a transmitting antenna.
  • the working frequency range of the antenna covers the entire 200MHz bandwidth working range of the radar transponder (S-band: 2.9G ⁇ 3.1G, X-band: 9.3G ⁇ 9.5G).
  • 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 the system response signal to space. Since the transmitting and receiving antennas need to work at the same time, in order to avoid system self-excitation, the isolation between the transmitting and receiving antennas must be 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 transceiver antennas is crucial to this system.
  • the transmitting and receiving antennas need to be installed up and down in a basically vertical state, and the farther apart, the better.
  • a radio signal isolation board can be added between the transmitting and receiving antennas in the structural design.
  • the isolation board 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 isolating plate is generally round, square, etc. The center of the isolating plate is approximately on the connection line of 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.
  • the transmit power can be increased to increase the response distance.
  • the RF transceiver module consists of a RF receiving link and a RF transmitting link.
  • the working frequency range of the radio frequency transceiver link covers the entire 200MHz bandwidth working range of the radar transponder (S-band: 2.9G ⁇ 3.1G, X-band: 9.3G ⁇ 9.5G).
  • the RF receiving link and RF transmitting link are composed of core components such as filters, amplifiers, and mixers.
  • the RF transceiver link shares the local oscillator module.
  • the radio frequency receiving link is used to convert the radio frequency 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 radio frequency transmitting link is used to convert the intermediate frequency signal output by the DAC playback module of the baseband processing module into a radio frequency signal output. Give the transmitting antenna.
  • the baseband processing module is mainly composed of ADC acquisition module, FPGA processing module and 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 radio frequency transmitter.
  • the sampling rate settings of the ADC acquisition module and DAC playback module need to ensure that signals within the 200MHz bandwidth of the entire radar transponder can be collected in the full frequency band.
  • the FPGA processing module is the core module of the system of the present invention and mainly implements orthogonal down-conversion processing, envelope detection, Morse code modulation and orthogonal up-conversion processing of ADC collected data.
  • Morse code modulation is one of the core processing links of the system in this embodiment, and consists of three parts: a tap delay, a coding switch, and a superposition module.
  • the tap delay is implemented using 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 level of delay module is the same and can be set. In order to optimize the display effect, each level of delay module can be divided into multi-level sub-delays. .
  • the tap data is led from the input of the tap delayer and the output of each stage delay module to the encoding switch module; the encoding switch module is a switch array, and each tap data corresponds to an on-off switch.
  • the on-off of the switch is controlled by the Morse code setting value.
  • the Morse code encoding setting value is obtained by searching the Morse code mapping relationship table prepared by the present invention according to the Morse code symbol.
  • the Morse code mapping relationship table is a table of correspondence between Morse code symbols and Morse code setting values.
  • the Morse code symbols include A ⁇ Z, 0 ⁇ 9, NW, NE, SW, SE, and the Morse code setting value bits The number is the same as the number of tap data channels, sorted from high to low.
  • Each 1 bit of the Morse code setting value is called a basic symbol unit, and each 1 bit of the Morse code setting value controls an on-off switch in the coding switch module.
  • the function of the Morse code mapping relationship table is to map the "dot-dash-empty" representation method corresponding to the Morse symbol into the Morse code setting value.
  • the basic principle of mapping is that "dot” or “dash” is represented by 1, and “empty” “Represented by 0 between "dot-dot”, “dot-dash”, “dash-dot” and “dash-dash”, "dot” and "empty” occupy the same number of bits, and "dash” occupies the same number of bits.
  • the number of bits is 3 times the number of bits occupied by "dot” or "empty”.
  • the encoding switch module outputs the gated tap data to the superposition module to participate in the superposition; the superposition module superimposes all the input tap data into a coded modulation waveform output.
  • 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 status of other parts.
  • the radome design has a certain impact on the isolation of the transceiver antenna of the system of the present invention, and the radome design and the transceiver antenna design should be considered comprehensively.
  • this embodiment provides a more specific design and working method under the system architecture:
  • the receiving antenna (X: 9.3 ⁇ 9.5G, omnidirectional, horizontal polarization, pitch angle 22°, gain 6dBi, isolation between transmitting and receiving antennas 85dB) receives radar transmission signals within the working frequency range from space;
  • the radio frequency receiving link (input: 9.3 ⁇ 9.5GHz, output: 600 ⁇ 800MHz, gain: 30dB) filters, amplifies, mixes, filters and amplifies the radio frequency signal output by the receiving antenna and outputs an intermediate frequency signal;
  • the ADC acquisition module (sampling rate 1Gbps) of the baseband processing module converts the intermediate frequency analog signal output from the radio frequency receiving link into a digital signal (4 parallel channels @250MHz) and outputs it;
  • the FPGA processing module of the baseband processing module receives the digital signal output from the ADC acquisition module and performs DDC processing on it (local oscillator frequency 700MHz, filter bandwidth 200MHz, 4 pumps), and moves the received signal to baseband (1 channel signal, sampling rate 250Mbps);
  • the Morse code modulation module in the FPGA processing module receives the baseband signal output from the DDC processing module and performs Morse code modulation processing on it;
  • the DUC module in the FPGA processing module receives the output of the Moss code modulation module and performs up-conversion processing on it. After processing, it outputs an intermediate frequency digital signal (4 parallel channels @ 250MHz);
  • 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 outputs it (channel 1, 600 ⁇ 800MHz);
  • the radio frequency transmission link (input: 600 ⁇ 800MHz, output: 9.3 ⁇ 9.5GHz, gain: 50dB) filters, amplifies, mixes, filters, and amplifies the intermediate frequency analog signal output by the DAC playback module in the baseband processing module and outputs it RF signals;
  • the transmitting antenna (X: 9.3 ⁇ 9.5G, omnidirectional, horizontal polarization, pitch angle 22°, gain 6dBi, isolation between transmitting and receiving antennas 85dB) radiates the RF signal output by the RF transmitting link into space.

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Abstract

本发明提出一种数字全宽带直接转发式雷达应答器系统及其工作方法，其提出了一种全新的雷达应答器系统架构及与之对应的新的莫斯编码识读方案。本发明系统采用直接转发式体系架构，该架构结合了数字宽带DRFM实时转发技术及以点代线的编码响应架构。收发天线独立且同时工作，对工作频段内的所有雷达问询信号直接无差别编码转发，保留了完整波形信息的同时实现了对响应信息的莫斯编码。本发明系统可等效于一个具有特殊目标特性的目标，工作频段内的雷达信号照射到该目标后会产生具有指定莫斯编码调制特性的回波信号。

Description

数字全宽带直接转发式雷达应答器系统及其工作方法 技术领域
本发明属于无线电导航技术领域，尤其涉及一种数字全宽带直接转发式雷达应答器系统及其工作方法。
背景技术
雷达应答器一般是用于标识浮标、灯塔、港口、海岸和其它具有航海意义物体的助航装置。当检测到雷达询问信号后雷达应答器产生代表特定含义的莫斯编码响应信号。
现有的雷达应答器主要有扫频和捷变频两种实现方式，目前扫频雷达应答器已经被淘汰。捷变频雷达应答器含有附加电路，用以测定每一个接收到的询问脉冲频率，并迅速地的调谐应答信号频率，以便与其保持一致。
当前工作的主流捷变频雷达应答器为模拟体制应答器，其工作原理是：通过检波、主瓣检测及测频电路获取需要响应波形的起始频率及脉宽，获取到起始频率后通过压控振荡器产生点频脉冲响应信号。压控振荡器产生的响应波形通过门控开关后输出，门控开关的选通时间受莫斯编码值控制。
技术问题
当前主流雷达应答器系统存在以下不足：
1)对雷达发射波形及信号处理体制敏感，仅能适用于窄带、简单调制雷达波形，无法适应新体制宽带、复杂调制波形，限制了新体制雷达在航海雷达领域的应用；
2)天线采用收发分时复用体制，发射信号期间不能对雷达询问进行响应，在港口等雷达密集场景会造成处理能力饱和，从而失去对周围雷达询问信号的有效响应；
3)采用测频生成式，响应之前需要对雷达询问信号进行频率、幅度等参数的测量及识别，当周边存在发射相同波形的雷达时容易造成误识别。
技术解决方案
针对现有技术存在的不足，为了解决当前雷达应答器无法应答具有宽带、复杂调制波形的新体制雷达的问题，本发明的目的在于提供一种数字全宽带直接转发式雷达应答器系统及其工作方法。
传统雷达应答器体制采用测频-生成式体系架构，该架构收发分时共用同一个天线，产生应答信号前需要检测输入信号的参数特征并将其与参数库中已有雷达参数进行匹配识别，当确定该输入信号为雷达主瓣信号后按测得频率参数产生点频脉冲响应信号。产生的响应波形通过门控开关后输出，门控开关的选通时间受莫斯编码值控制。由于传统雷达应答器的响应波形为简单点频脉冲信号，丢失了大部分波形参数信息，因此，传统雷达应答器无法响应具有大带宽、复杂调制波形的新体制雷达波形。
为了实现对新体制雷达的应答，本发明系统提出了一种全新的雷达应答器系统架构及与之对应的新的莫斯编码识读方案。本发明系统采用直接转发式体系架构，该架构结合了数字宽带DRFM实时转发技术及以点代线的编码响应架构。收发天线独立且同时工作，对工作频段内的所有雷达问询信号直接无差别编码转发，保留了完整波形信息的同时实现了对响应信息的莫斯编码。本发明系统可等效于一个具有特殊目标特性的目标，工作频段内的雷达信号照射到该目标后会产生具有指定莫斯编码调制特性的回波信号。
本发明系统的核心之一还包括莫斯编码调制的实现及莫斯编码的识读方法。标准莫斯编码由“点”“空”“划”三个基本符号构建，“点”与“划”为实线，“点”与“空”的长度相等，“划”为“点”或“空”长度的三倍。传统雷达应答器应答的莫斯码的点、划在雷达上显示为径向实线，且长度满足标准莫斯编码规则。为了实现对新体制雷达的应答，本发明系统采用了一种以点代线的莫斯编码响应架构代替当前莫斯编码效果，该编码架构的编码原则为：1)若干回波点代替莫斯码中的“点”，每个回波点占据一个基本符号单元；2)莫斯码中的“划”用三倍于“点”的回波点代替，占据三倍于“点”的基本符号单元；3)莫斯码中的“空”占据与“点”相同的基本符号单元数；4)每个回波点在雷达上显示的距离取决于雷达分辨率，不再等于一个基本符号单元。按以上编码原则识别莫斯码不再依靠“点”、“空”及“划”的绝对距离比例关系，主要依据回波点数量关系及起点间距离，只要保证基本符号单元大于雷达的最小分辨距离单元即可轻松识别接收到的莫斯编码。
本发明具体采用以下技术方案：
一种数字全宽带直接转发式雷达应答器系统，其特征在于，包括：由接收天线及发射天线组成的天线系统、由射频接收链路及射频发射链路组成的射频收发模块，以及包括ADC采集模块、FPGA处理模块及DAC播放模块的基带处理模块；
所述接收天线用于从空间接收工作频段范围内雷达发射信号，发射天线用于将系统响应信号辐射到空间；
射频收发链路共用本振模块；所述射频接收链路用于将接收天线输出的射频信号转换为中频信号输出给基带处理模块的ADC采集模块；所述射频发射链路用于将基带处理模块的DAC播放模块输出的中频信号转换为射频信号输出给发射天线；
所述ADC采集模块将射频接收机输出的中频模拟信号转换为数字信号并送入FPGA处理模块；所述DAC播放模块将FPGA处理模块输出的数字信号转换为模拟信号并送入射频发射机的中频模拟输入接口；所述FPGA处理模块用于实现ADC采集数据的正交下变频处理、包络检波、莫斯编码调制及正交上变频处理。
进一步地，所述莫斯编码调制由抽头延迟器、编码开关模块及叠加模块三部分实现；
所述抽头延迟器采用多级延迟抽头叠加架构，延迟模块间首尾相连形成延迟链，每级延迟模块的延迟值相同且可调；抽头数据从抽头延迟器输入及每级延迟模块输出引出至编码开关模块；
所述编码开关模块为一个开关阵列，每路抽头数据对应一个通断开关，开关的通断受莫斯编码设置值控制；莫斯码编码设置值根据莫斯码符号通过查找莫斯码映射关系表获得；编码开关模块输出被选通的抽头数据到叠加模块参与叠加；
所述叠加模块将输入的所有抽头数据叠加为1路编码调制波形输出。
进一步地，所述莫斯码映射关系表将莫斯符号对应的“点-划-空”表示方法映射为莫斯编码设置值；映射的基本原则是“点”或“划”用1表示，“空”用“点-点”、“点-划”、“划-点”、“划-划”间的0表示，“点”和“空”所占bit位数相同，“划”所占bit位数为“点”或“空”所占bit位数的3倍，满 足“点”、“划”、“空”相对关系前提下占用莫斯编码设置值对应数据的最大长度。
进一步地，所述天线系统的工作频段范围覆盖整个雷达应答器的200MHz带宽工作范围，收发天线间的隔离度大于系统总增益；所述射频收发链路的工作频段范围覆盖整个雷达应答器的200MHz带宽工作范围，所述射频接收链路及射频发射链路均包括有：滤波器、放大器和混频器；所述ADC采集模块及DAC播放模块的采样率设置需保证能够对整个雷达应答器的200MHz带宽范围内的信号进行全频段采集。
进一步地，还包括天线罩，用于保护各组件模块，防止环境对各组件模块工作状态的影响和干扰。
进一步地，其工作方法包括以下步骤：
步骤S1：上电并进行初始化；
步骤S2：接收天线从空间接收工作频段范围内的雷达发射信号；
步骤S3：射频接收链路对接收天线输出的射频信号进行滤波、放大、混频、滤波、放大后输出中频信号；
步骤S4：基带处理模块的ADC采集模块对射频接收链路输出的中频模拟信号模数转换，转换为数字信号并输出；
步骤S5：基带处理模块的FPGA处理模块接收ADC采集模块输出的数字信号并对其进行DDC处理，将接收信号搬移到基带；
步骤S6：FPGA处理模块中的莫斯编码调制模块接收DDC处理模块输出的基带信号并对其进行莫斯编码调制处理；
步骤S7：FPGA处理模块中的DUC模块接收莫斯编码调制模块的输出并对其进行上变频处理，处理后输出中频数字信号；
步骤S8：基带处理模块的DAC播放模块对FPGA处理模块中DUC模块输出的中频数字信号进行数模转换，转换为模拟中频信号后输出；
步骤S9：射频发射链路对基带处理模块DAC播放模块输出的中频模拟信号进行滤波、放大、混频、滤波、放大后输出射频信号；
步骤S10：发射天线将射频发射链路输出的射频信号辐射到空间。
有益效果
与现有技术相比，本发明及其优选方案收发天线独立且同时工作，无需检测及识别输入信号的参数特征，对所有雷达问询信号实现无差别编码转发。其有益效果包括：
1)对雷达发射波形及信号处理体制不敏感，在兼容传统雷达信号前提下可响应具有复杂调制波形的新体制雷达信号，使新技术、新体制应用于船舶导航雷达系统成为可能；
2)能够同时可靠响应所有接收到的雷达问询信号，即使多部雷达问询信号在时域或频域上有叠加部分；
3)对雷达发射旁瓣具有天然的抑制能力；
4)具有更小的系统延时，即具有较高的距离精度。
附图说明
下面结合附图和具体实施方式对本发明进一步详细的说明：
图1为本发明实施例提供的系统组成框图；
图2为本发明实施例莫斯编码调制模块实现框图；
图3为本发明实施例莫斯编码调制原理示意图；
图4为本发明实施例莫斯码映射关系表。
本发明的实施方式
为让本专利的特征和优点能更明显易懂，下文特举实施例，作详细说明如下：
下面结合附图和实施例对本发明的技术方案做进一步的说明。
在下面的描述中阐述了很多具体细节以便于充分理解本发明，但是，本发明还可以采用其他不同于在此描述范围内的其他方式来实施，因此，本发明的保护范围并不受下面公开的具体实施例的限制。
如图1所示，本实施例提供的数字全宽带直接转发式雷达应答器系统，包括以下部分：
(1)接收天线，(2)射频接收链路，(3)基带处理模块，(4)射频发射链路，(5)发射天线。
其中，(1)接收天线，用于从空间接收工作频段范围内的雷达发射信号；
(2)射频接收链路，用于对接收天线输出的射频信号进行滤波、放大、混频、滤波、放大后输出中频信号；
(3)基带处理模块，用于对射频接收链路输出的中频模拟信号进行ADC采集、数字下变频、莫斯编码调制、数字上变频及DAC播放；
(4)射频发射链路，用于对基带处理模块DAC播放模块输出的中频模拟信号进行滤波、放大、混频、滤波、放大后输出射频信号；
(5)发射天线，用于将射频发射链路输出的射频信号辐射到空间。
在本实施例中，上述组成部件间的连接关系为：从(1)至(5)，上一个模块的输出依次连接到下一个模块的输入，从而构成系统基本的组成。
以下分别对本实施例系统的各个组成部分进行说明。
天线系统：天线系统由接收天线及发射天线组成。天线的工作频段范围覆盖整个雷达应答器的200MHz带宽工作范围(S波段：2.9G～3.1G，X波段：9.3G～9.5G)。接收天线用于从空间接收工作频段范围内雷达发射信号，发射天线用于将系统响应信号辐射到空间。由于收发天线需要同时工作，为避免系统自激，收发天线间的隔离度必须大于系统总增益。系统增益与应答距离成正比，为增大响应距离，高隔离度收发天线设计对本系统至关重要。高隔离度天线设计的两个可行途径为：1)收发天线本身参数及布局优化设计2)增加对消支路，也可将以上两种途径结合。收发天线安装需要上下放置，均成基本垂直状态，并且相隔越远越好。为了紧凑，结构设计上可以在收发天线之间增加一块无线电信号隔离板。隔离板由对无线电信号有隔离或屏蔽效应的金属等材料制成。收发天线约在一条垂直线上或稍有错开。隔离板一般为圆形、方形等，隔离板中心约在两个天线的连线上，并靠近两个天线之间的中间位置，约成水平状态，与天线垂直，以避免系统自激，从而可以增加发射功率达到增大响应距离的效果。
射频收发模块：射频收发模块由射频接收链路及射频发射链路组成。射频收发链路的工作频段范围覆盖整个雷达应答器的200MHz带宽工作范围(S波段：2.9G～3.1G，X波段：9.3G～9.5G)。射频接收链路及射频发射链路均由滤波器、放大器、混频器等核心器件组成，射频收发链路共用本振模块。射频接收链路用于将接收天线输出的射频信号转换为中频信号输出给基带处理模块的ADC采集模块，射频发射链路用于将基带处理模块的DAC播放模块输出的中频信号转换为射频信号输出给发射天线。
基带处理模块：基带处理模块主要由ADC采集模块、FPGA处理模块及DAC播放模块组成。ADC采集模块将射频接收机输出的中频模拟信号转换为数字信 号并送入FPGA处理模块。DAC播放模块将FPGA处理模块输出的数字信号转换为模拟信号并送入射频发射机的中频模拟输入接口。ADC采集模块及DAC播放模块的采样率设置需保证能够对整个雷达应答器的200MHz带宽范围内的信号进行全频段采集。FPGA处理模块是本发明系统的核心模块，主要实现ADC采集数据的正交下变频处理、包络检波、莫斯编码调制及正交上变频处理。
如图2到图4所示，其中，莫斯编码调制是本实施例系统的核心处理环节之一，由抽头延迟器、编码开关及叠加模块三部分组成。抽头延迟器采用多级延迟抽头叠加架构实现，延迟模块间首尾相连形成延迟链，每级延迟模块的延迟值相同且可设置，为优化显示效果每级延迟模块内部又可划分为多级子延迟。抽头数据从抽头延迟器输入及每级延迟模块输出引出至编码开关模块；编码开关模块为一个开关阵列，每路抽头数据对应一个通断开关，开关的通断受莫斯编码设置值控制。莫斯码编码设置值根据莫斯码符号通过查找本发明编制的莫斯码映射关系表获得。莫斯码映射关系表是一张莫斯编码符号与莫斯编码设置值对应关系表，莫斯编码符号包含A～Z、0～9、NW、NE、SW、SE，莫斯编码设置值位数与抽头数据路数相同，从高到低依次排序。莫斯编码设置值的每1bit称为一个基本符号单元，莫斯编码设置值的每1bit控制编码开关模块中的一个通断开关。莫斯码映射关系表的作用是把莫斯符号对应的“点-划-空”表示方法映射为莫斯编码设置值，映射的基本原则是“点”或“划”用1表示，“空”用“点-点”、“点-划”、“划-点”、“划-划”间的0表示，“点”和“空”所占bit位数相同，“划”所占bit位数为“点”或“空”所占bit位数的3倍，满足“点”、“划”、“空”相对关系前提下占用莫斯编码设置值对应数据的最大长度。编码开关模块输出被选通的抽头数据到叠加模块参与叠加；叠加模块将输入的所有抽头数据叠加为1路编码调制波形输出。
天线罩：天线罩用于保护本发明系统其它部位，防止环境对其它部位工作状态的影响和干扰。同时天线罩设计对本发明系统的收发天线隔离度有一定影响，天线罩设计与收发天线设计应该综合考虑。
基于以上系统及涉及原则，作为优选，本实施例提供该系统架构下更为具体的设计和工作方法：
1)系统上电并进行初始化；
2)给基带处理模块的莫斯编码调制模块下发莫斯编码配置值：19’b111_1111_1100_0111_0000(莫斯编码：N)及抽头延迟器延时值：500(对应基本符号单元长度：500*4ns＝2us)；
3)接收天线(X：9.3～9.5G，全向，水平极化，俯仰角度22°，增益6dBi，收发天线间隔离度85dB)从空间接收工作频段范围内的雷达发射信号；
4)射频接收链路(输入：9.3～9.5GHz，输出：600～800MHz，增益：30dB)对接收天线输出的射频信号进行滤波、放大、混频、滤波、放大后输出中频信号；
5)基带处理模块的ADC采集模块(采样率1Gbps)对射频接收链路输出的中频模拟信号模数转换，转换为数字信号(4路并行@250MHz)并输出；
6)基带处理模块的FPGA处理模块(FPGA型号：xc7v325t-ffg900)接收ADC采集模块输出的数字信号并对其进行DDC处理(本振频率700MHz,滤波器带宽200MHz,4抽)，将接收信号搬移到基带(1路信号，采样率250Mbps)；
7)FPGA处理模块中的莫斯编码调制模块接收DDC处理模块输出的基带信号并对其进行莫斯编码调制处理；
8)FPGA处理模块中的DUC模块(本振频率700MHz,滤波器带宽200MHz,4插值)接收莫斯编码调制模块的输出并对其进行上变频处理，处理后输出中频数字信号(4路并行@250MHz)；
9)基带处理模块的DAC播放模块对FPGA处理模块中DUC模块输出的中频数字信号进行数模转换，转换为模拟中频信号后输出(1路，600～800MHz)；
10)射频发射链路(输入：600～800MHz，输出：9.3～9.5GHz，增益：50dB)对基带处理模块中DAC播放模块输出的中频模拟信号进行滤波、放大、混频、滤波、放大后输出射频信号；
11)发射天线(X：9.3～9.5G，全向，水平极化，俯仰角度22°，增益6dBi，收发天线间隔离度85dB)将射频发射链路输出的射频信号辐射到空间。
以上所述，仅是本发明的较佳实施例而已，并非是对本发明作其它形式的限制，任何熟悉本专业的技术人员可能利用上述揭示的技术内容加以变更或改型为等同变化的等效实施例。但是凡是未脱离本发明技术方案内容，依据本发明的技术实质对以上实施例所作的任何简单修改、等同变化与改型，仍属于本发明技术方案的保护范围。
显然，本发明的上述实施例仅是为清楚地说明本发明所作的举例，而并非是对本发明的实施方式的限定。对于所属领域的普通技术人员来说，在上述说明的基础上还可以做出其它不同形式的变化或变动。这里无需也无法对所有的实施方式予以穷举。凡在本发明的精神和原则之内所作的任何修改、等同替换和改进等，均应包含在本发明权利要求的保护范围之内。

Claims (6)

  1. 一种数字全宽带直接转发式雷达应答器系统，其特征在于，包括：由接收天线及发射天线组成的天线系统、由射频接收链路及射频发射链路组成的射频收发模块，以及包括ADC采集模块、FPGA处理模块及DAC播放模块的基带处理模块；
    所述接收天线用于从空间接收工作频段范围内雷达发射信号，发射天线用于将系统响应信号辐射到空间；
    射频收发链路共用本振模块；所述射频接收链路用于将接收天线输出的射频信号转换为中频信号输出给基带处理模块的ADC采集模块；所述射频发射链路用于将基带处理模块的DAC播放模块输出的中频信号转换为射频信号输出给发射天线；
    所述ADC采集模块将射频接收机输出的中频模拟信号转换为数字信号并送入FPGA处理模块；所述DAC播放模块将FPGA处理模块输出的数字信号转换为模拟信号并送入射频发射机的中频模拟输入接口；所述FPGA处理模块用于实现ADC采集数据的正交下变频处理、包络检波、莫斯编码调制及正交上变频处理。
  2. 根据权利要求1所述的数字全宽带直接转发式雷达应答器系统，其特征在于：所述莫斯编码调制由抽头延迟器、编码开关模块及叠加模块三部分实现；
    所述抽头延迟器采用多级延迟抽头叠加架构，延迟模块间首尾相连形成延迟链，每级延迟模块的延迟值相同且可调；抽头数据从抽头延迟器输入及每级延迟模块输出引出至编码开关模块；
    所述编码开关模块为一个开关阵列，每路抽头数据对应一个通断开关，开关的通断受莫斯编码设置值控制；莫斯码编码设置值根据莫斯码符号通过查找莫斯码映射关系表获得；编码开关模块输出被选通的抽头数据到叠加模块参与叠加；
    所述叠加模块将输入的所有抽头数据叠加为1路编码调制波形输出。
  3. 根据权利要求2所述的数字全宽带直接转发式雷达应答器系统，其特征在于：所述莫斯码映射关系表将莫斯符号对应的“点-划-空”表示方法映射为莫斯编码设置值；映射的基本原则是“点”或“划”用1表示，“空”用“点-点”、“点-划”、“划-点”、“划-划”间的0表示，“点”和“空”所占bit位数相同，“划”所占bit位数为“点”或“空”所占bit位数的3倍，满足“点”、“划”、“空”相对关系前提下占用莫斯编码设置值对应数据的最大长度。
  4. 根据权利要求1所述的数字全宽带直接转发式雷达应答器系统，其特征在于：所述天线系统的工作频段范围覆盖整个雷达应答器的200MHz带宽工作范围，收发天线间的隔离度大于系统总增益；所述射频收发链路的工作频段范围覆盖整个雷达应答器的200MHz带宽工作范围，所述射频接收链路及射频发射链路均包括有：滤波器、放大器和混频器；所述ADC采集模块及DAC播放模块的采样率设置需保证能够对整个雷达应答器的200MHz带宽范围内的信号进行全频段采集。
  5. 根据权利要求1所述的数字全宽带直接转发式雷达应答器系统，其特征在于：还包括天线罩，用于保护各组件模块，防止环境对各组件模块工作状态的影响和干扰。
  6. 根据权利要求3所述的数字全宽带直接转发式雷达应答器系统的工作方法，其特征在于，包括以下步骤：
    步骤S1：上电并进行初始化；
    步骤S2：接收天线从空间接收工作频段范围内的雷达发射信号；
    步骤S3：射频接收链路对接收天线输出的射频信号进行滤波、放大、混频、滤波、放大后输出中频信号；
    步骤S4：基带处理模块的ADC采集模块对射频接收链路输出的中频模拟信号模数转换，转换为数字信号并输出；
    步骤S5：基带处理模块的FPGA处理模块接收ADC采集模块输出的数字信号并对其进行DDC处理，将接收信号搬移到基带；
    步骤S6：FPGA处理模块中的莫斯编码调制模块接收DDC处理模块输出的基带信号并对其进行莫斯编码调制处理；
    步骤S7：FPGA处理模块中的DUC模块接收莫斯编码调制模块的输出并对其进行上变频处理，处理后输出中频数字信号；
    步骤S8：基带处理模块的DAC播放模块对FPGA处理模块中DUC模块输出的中频数字信号进行数模转换，转换为模拟中频信号后输出；
    步骤S9：射频发射链路对基带处理模块DAC播放模块输出的中频模拟信 号进行滤波、放大、混频、滤波、放大后输出射频信号；
    步骤S10：发射天线将射频发射链路输出的射频信号辐射到空间。
PCT/CN2022/081110 2022-03-07 2022-03-16 数字全宽带直接转发式雷达应答器系统及其工作方法 WO2023168734A1 (zh)

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