A passive radar target return simulation system

Abstract

The application discloses a passive radar target echo simulation system, comprising: a radio frequency signal generator, a power division unit and an amplitude and phase control unit connected in sequence; a total control unit connected with the radio frequency signal generator and the amplitude and phase control unit; the total control unit is used for analyzing the received control command, obtaining the passive radar working parameters and target parameters, and converting the passive radar working parameters and target parameters into first control instructions and second control instructions; the radio frequency signal generator is used for generating a reference microwave signal according to the first control instructions; the power division unit is used for dividing the received reference microwave signal into N microwave signals; the amplitude and phase control unit is used for receiving the second control instructions, adjusting the output amplitude and output phase of the N microwave signals according to the second control instructions, and then outputting the N microwave signals after being combined, and the application solves the problems of small instantaneous bandwidth and low simulation precision of multi-target echo characteristics.

Description

Technical Field

[0001] This invention relates to the field of radar detection technology, and in particular to a passive radar target echo simulation system. Background Technology

[0002] For passive radar, radar target echo simulation systems that use a single target model to simulate the frequency, power, and other basic characteristics of the echo signal are no longer sufficient to meet the requirements for accurate performance testing of passive radar systems. We need to consider echo simulation of multiple targets. The direction of arrival of the radar signal is one of the important characteristics for distinguishing different targets. Passive radar typically uses the differences in amplitude, phase, and time response of different incoming signals to calculate angular information.

[0003] Existing passive radar target echo simulation systems considering multi-target models mostly employ direct digital synthesis (DDS) to generate baseband signals. After delay and convolutional modulation based on target characteristics, the signals are played back by a digital-to-analog converter (DAC) and then converted into radio frequency signals via an up-conversion circuit. In this method, the instantaneous bandwidth of the passive radar signal is constrained by the sampling and output performance of the DAC chip. Furthermore, the up-conversion circuit introduces a certain degree of nonlinear distortion into the signal's amplitude and phase, resulting in low accuracy of the final simulated multi-target echo characteristics. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide a passive radar target echo simulation system, which solves the problems of small instantaneous bandwidth and low accuracy of multi-target echo characteristic simulation caused by the sampling and output performance of the DAC chip in the original passive radar target echo simulation system.

[0005] To solve the above problems, the present invention is achieved through the following technical solution:

[0006] A passive radar target echo simulation system includes: a radio frequency signal generator 20, a power divider unit 30, and an amplitude and phase control unit 40 connected in sequence; a central control unit 10 connected to the radio frequency signal generator 20 and the amplitude and phase control unit 40 respectively; the central control unit 10 is used to parse the received control commands to obtain passive radar operating parameters and target parameters, and convert the passive radar operating parameters and target parameters into a first control command and a second control command; the radio frequency signal generator 20 is used to generate a reference microwave signal according to the first control command; the power divider unit 30 is used to divide the received reference microwave signal into N microwave signals, where N is a positive integer and N≥2; the amplitude and phase control unit 40 is used to receive the second control command, adjust the output amplitude and output phase of the N microwave signals respectively according to the second control command, and then synthesize the N microwave signals and output them.

[0007] Optionally, the central control unit 10 includes a target echo modeling module 101, an amplitude and phase calibration module 102, and a communication control module 103. The communication control module 103 is connected to the target echo modeling module 101, the amplitude and phase calibration module 102, the radio frequency signal generator 20, and the amplitude and phase control unit 40, respectively. The communication control module 103 receives externally input control commands, parses the control commands to obtain passive radar operating parameters and target parameters, and transmits them to the target echo modeling module 101. The target echo modeling module 101 constructs different scene models based on the passive radar operating parameters and target parameters. The target echo simulation signal is transmitted back to the communication control module 103; the amplitude and phase calibration module 102 is used to calibrate the amplitude and phase of the N output channels of the amplitude and phase control unit 40 during the initialization phase of the passive radar target echo simulation system, and to test the initial amplitude and phase difference of the N output channels at different operating frequencies with the help of the network analyzer, and record the calibration results; the communication control module 103 is also used to read the calibration results and the target echo simulation signal, and convert them into the first control command and send them to the radio frequency signal generator 20, and convert them into the second control command and send them to the amplitude and phase control unit 40.

[0008] Optionally, the first control instruction includes: pulse width change instruction, repetition rate change instruction, frequency change instruction, power change instruction, and signal on / off instruction; the second control instruction includes: N-channel amplitude change instruction and N-channel phase change instruction.

[0009] Optionally, the radio frequency signal generator 20 sets the pulse width of the output reference microwave signal according to the pulse width change instruction; sets the pulse repetition period of the output reference microwave signal according to the repetition frequency change instruction; sets the frequency of the output reference microwave signal according to the frequency change instruction; sets the power of the output reference microwave signal according to the power change instruction; and sets whether to output the reference microwave signal according to the signal on / off instruction.

[0010] Optionally, the power divider unit 30 includes: a power divider 301 and a power amplifier 302 connected to each other; the power divider 301 is used to divide the reference microwave signal into the N microwave signals; the power amplifier 302 is used to output the N microwave signals after power compensation.

[0011] Optionally, the amplitude-phase control unit 40 includes: an amplitude-phase decoding circuit 401, N digitally controlled attenuators (A1-An), N digitally controlled phase shifters (B1-Bn), and a power combiner 402; the power amplifier 302 is connected to the N digitally controlled attenuators (A1-An) respectively, and the N digitally controlled attenuators (A1-An) and the N digitally controlled phase shifters (B1-Bn) are connected in a one-to-one correspondence; the N digitally controlled phase shifters (B1-Bn) are connected to the power combiner 402; the amplitude-phase decoding circuit 401 is used to decode the amplitude of the N channels. The system uses an amplitude change command and an N-channel phase change command to acquire the phase and amplitude information of N microwave signals and convert them into amplitude control signals and phase control signals, respectively. The N numerically controlled attenuators (A1 to An) are used to attenuate the power of the N microwave signals according to the amplitude control signals. The N numerically controlled phase shifters (B1 to Bn) are used to shift the phase of the N microwave signals according to the phase control signals. The power combiner 402 is used to combine the power-attenuated and phase-shifted N microwave signals into an echo signal carrying multi-target information for output.

[0012] Optionally, the operating bandwidth of the radio frequency signal generator 20, the digitally controlled attenuator (A1~An) and the digitally controlled phase shifter (B1~Bn) is greater than 10 GHz.

[0013] Optionally, the main control unit 10 communicates with the radio frequency signal generator 20 and the amplitude and phase control unit 40 via a network cable.

[0014] Optionally, the echo signal U carrying multi-target information R (t):

[0015]

[0016] In the formula, m represents the number of targets, and A i φ i These are the echo amplitude and relative phase of the i-th target, respectively, f A t represents the frequency of the target echo signal and t represents time.

[0017] Optionally, in the amplitude and phase control unit, a digitally controlled attenuator plus a digitally controlled phase shifter constitutes a channel to simulate the generation of an echo signal from a single target.

[0018] This invention has one of the following advantages:

[0019] This invention provides a passive radar target echo simulation system considering a multi-target model. The radio frequency signal generator, digitally controlled attenuator, and digitally controlled phase shifter used in the system all have operating bandwidths greater than 10 GHz, making them applicable to passive radars with different operating frequencies and instantaneous bandwidths, thus exhibiting excellent versatility. The system provides initial amplitude and phase calibration functions for each channel, ensuring the simulation accuracy of multi-target echoes at different operating frequencies. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of a passive radar target echo simulation system provided in an embodiment of the present invention;

[0021] Figure 2 This is a schematic diagram of the hardware architecture of a passive radar target echo simulation system provided in an embodiment of the present invention;

[0022] Figure 3 This is a block diagram of the composition structure of the master control unit provided in an embodiment of the present invention. Detailed Implementation

[0023] The passive radar target echo simulation system proposed in this invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. The advantages and features of this invention will become clearer from the following description. It should be noted that the drawings are in a very simplified form and use non-precise proportions, only for the purpose of conveniently and clearly illustrating the embodiments of this invention. Please refer to the drawings to make the objectives, features, and advantages of this invention more apparent and understandable. It should be understood that the structures, proportions, sizes, etc., depicted in the accompanying drawings are only for the purpose of assisting those skilled in the art in understanding and reading the content disclosed in the specification, and are not intended to limit the implementation conditions of this invention. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportional relationships, or adjustments to the size, without affecting the effects and objectives achieved by this invention, should still fall within the scope of the technical content disclosed in this invention.

[0024] like Figure 1 As shown, a passive radar target echo simulation system includes: a radio frequency signal generator 20, a power divider unit 30, and an amplitude and phase control unit 40 connected in sequence; and a main control unit 10, which is connected to the radio frequency signal generator 20 and the amplitude and phase control unit 40 respectively.

[0025] The central control unit 10 is used to parse the received control commands to obtain passive radar operating parameters and target parameters. The central control unit 10 is also used to construct a multi-target echo signal model, generate amplitude and phase information of target echoes from multiple channels, and convert the passive radar operating parameters, target parameters, and amplitude and phase information of target echoes from multiple channels into a first control command and a second control command.

[0026] Specifically, the central control unit 10 can receive externally input control commands, parse the control commands to obtain passive radar operating parameters and target parameters, and calculate target echo simulation information based on conventional passive radar target echo models, such as conventional pulse signal models, frequency agile signal models, intra-pulse modulation signal models, repetition frequency correlation signals, continuous wave modulation signal models, etc. (i.e., existing commonly used echo models can be used for calculation, which will not be elaborated here). Then, the target echo simulation information is converted into different control commands and sent to the radio frequency signal generator and amplitude and phase control unit to control the coordinated operation of various units within the system.

[0027] The radio frequency signal generator 20 is used to generate a reference microwave signal according to the first control command; the power divider 30 is used to divide the received reference microwave signal into N microwave signals, where N is a positive integer and N≥2.

[0028] The amplitude and phase control unit 40 is used to receive the second control command, adjust the output amplitude and output phase of the N microwave signals according to the second control command, and then combine the N microwave signals and output them.

[0029] like Figure 3 As shown, the central control unit 10 includes a target echo modeling module 101, an amplitude and phase calibration module 102, and a communication control module 103. The communication control module 103 is connected to the target echo modeling module 101, the amplitude and phase calibration module 102, the radio frequency signal generator 20, and the amplitude and phase control unit 40, respectively. The communication control module 103 receives externally input control commands, parses the control commands to obtain passive radar operating parameters and target parameters, and transmits them to the target echo modeling module 101.

[0030] The target echo modeling module 101 constructs target echo simulation signals under different scenario models based on the passive radar operating parameters and target parameters, and transmits the target echo simulation signals from multiple channels back to the communication control module 103.

[0031] The amplitude and phase calibration module 102 is used to calibrate the amplitude and phase of the N output channels of the amplitude and phase control unit 40 (one digitally controlled attenuator plus one digitally controlled phase shifter constitutes one channel in the amplitude and phase control unit 40, which is N output channels in this embodiment) during the initialization phase of the passive radar target echo simulation system. It works with a network analyzer to test the initial amplitude and phase difference of the N output channels at different operating frequencies and records the calibration results.

[0032] The communication control module 103 can read the calibration results from the amplitude-phase calibration module and the calculation results from the target echo modeling module, and then convert them into different control commands to send to the radio frequency signal generator 20 and the amplitude-phase control unit 40. That is, the communication control module 103 is also used to read the calibration results and the target echo simulation signal, and convert them into the first control command to send to the radio frequency signal generator 20 and into the second control command to send to the amplitude-phase control unit 40.

[0033] In this embodiment, the first control command includes: pulse width change command, repetition rate change command, frequency change command, power change command, and signal on / off command; the second control command includes: N-channel amplitude change command and N-channel phase change command.

[0034] In this embodiment, the radio frequency signal generator 20 adopts a standard instrument architecture and supports remote control using SCPI language. The radio frequency signal generator 20 is connected to the central control unit 10 via a gigabit Ethernet port and is used to output a reference microwave signal according to the control commands of the central control unit 10. Specifically, the pulse width of the output reference microwave signal is set according to the pulse width change command; the pulse repetition period of the output reference microwave signal is set according to the repetition frequency change command; the frequency of the output reference microwave signal is set according to the frequency change command; the power of the output reference microwave signal is set according to the power change command; and whether to output the reference microwave signal is set according to the signal on / off command.

[0035] The preferred form of the reference microwave signal output by the radio frequency signal generator 20 is:

[0036] U R (t)=A0cos(2πf A t+φ0) (1)

[0037] In the formula: U R (t) represents the reference microwave signal, and A0 is the amplitude of the reference microwave signal; f A φ is the frequency of the reference microwave signal; φ0 is the initial phase; and t represents time.

[0038] like Figure 2 As shown, in this embodiment, the power division unit 30 includes: a power divider 301 and a power amplifier 302 connected to each other; the power divider 301 is used to divide the reference microwave signal into the N microwave signals; the power amplifier 302 is used to output the N microwave signals after power compensation.

[0039] Please continue to refer to this. Figure 2As shown, the amplitude-phase control unit 40 includes: an amplitude-phase decoding circuit 401, N digitally controlled attenuators (A1-An), N digitally controlled phase shifters (B1-Bn), and a power combiner 402; the power amplifier 302 is connected to the N digitally controlled attenuators (A1-An) respectively, and the N digitally controlled attenuators (A1-An) and the N digitally controlled phase shifters (B1-Bn) are connected in a one-to-one correspondence; the N digitally controlled phase shifters (B1-Bn) are connected to the power combiner 402. The amplitude-phase decoding circuit 401 is connected to the N digitally controlled attenuators (A1-An) and the N digitally controlled phase shifters (B1-Bn) respectively.

[0040] The amplitude-phase decoding circuit 401 is used to parse the N-channel amplitude change command and the N-channel phase change command, obtain the phase and amplitude information of the N microwave signals (signals of each channel), and convert them into amplitude control signals and phase control signals. That is, the amplitude-phase decoding circuit 401 receives the N-channel amplitude change command from the central control unit 10 through the network port, converts it into amplitude control voltage signals that can be recognized by each digitally controlled attenuator, and sends them to the N digitally controlled attenuators (A1 to An), where N is a positive integer and N≥2.

[0041] The N digitally controlled attenuators (A1 to An) are used to attenuate the power of the N microwave signals according to the amplitude control signal. Each digitally controlled attenuator attenuates the power of each microwave signal output from the power divider unit 30 according to the received amplitude control voltage signal, thereby achieving amplitude adjustment.

[0042] The amplitude-phase decoding circuit 401 also receives the N-channel phase change command from the central control unit 10 through the network port, converts it into a phase control voltage signal that can be recognized by each numerically controlled phase shifter, and sends it to the N numerically controlled phase shifters (B1~Bn); where N is a positive integer and N≥2.

[0043] The N digitally controlled phase shifters (B1 to Bn) are used to shift the phase of the N microwave signals according to the phase control signal. That is, each digitally controlled phase shifter adjusts the phase of each microwave signal output from each digitally controlled attenuator according to the received phase control voltage signal.

[0044] The power combiner 402 is used to combine the N microwave signals after power attenuation and phase shifting into an echo signal carrying multi-target information for output.

[0045] The echo signal U carrying multi-target information R (t):

[0046]

[0047] In the formula, m represents the number of targets, and Ai φ i These are the echo amplitude and relative phase of the i-th target, respectively, f A t represents the frequency of the target echo signal and t represents time.

[0048] In this embodiment, the operating bandwidth of the radio frequency signal generator 20, the digitally controlled attenuators (A1-An), and the digitally controlled phase shifters (B1-Bn) are all greater than 10 GHz. This makes it applicable to passive radars with different operating frequencies and instantaneous bandwidths, demonstrating excellent versatility.

[0049] The amplitude and phase decoding circuit 401 uses a programmable logic circuit FPGA as the control chip. It receives the amplitude and phase control commands from the central control unit 10 transmitted through the network port. After parsing and decoding the commands according to the transmission protocol, it obtains the amplitude and phase information corresponding to the N channel echo signals. After converting them into amplitude / phase voltage control signals, they are output to each digitally controlled attenuator and digitally controlled phase shifter through a CMOS type three-state buffer gate circuit.

[0050] The main control unit 10 communicates with the radio frequency signal generator 20 and the amplitude and phase control unit 40 via a network cable.

[0051] In this embodiment, a digitally controlled attenuator and a digitally controlled phase shifter constitute a channel in the amplitude and phase control unit, which simulates the echo signal of a single target. The maximum number of targets that the system can simulate can be expanded by increasing the number of digitally controlled attenuators and digitally controlled phase shifters.

[0052] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0053] It should be noted that the apparatus and methods disclosed in the embodiments herein can also be implemented in other ways. The apparatus embodiments described above are merely illustrative; for example, the flowcharts and block diagrams in the accompanying drawings show the architecture, functionality, and operation of possible implementations of apparatus, methods, and computer program products according to various embodiments herein. In this regard, each block in a flowchart or block diagram may represent a module, program, or part of code containing one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions marked in the blocks may occur in a different order than those marked in the drawings. For example, two consecutive blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in a block diagram and / or flowchart, and combinations of blocks in block diagrams and / or flowcharts, can be implemented using a dedicated hardware-based system to perform the specified function or action, or can be implemented using a combination of dedicated hardware and computer instructions.

[0054] In addition, the functional modules in the various embodiments of this article can be integrated together to form an independent part, or each module can exist independently, or two or more modules can be integrated to form an independent part.

[0055] Although the present invention has been described in detail through the preferred embodiments above, it should be understood that the above description should not be considered as a limitation of the present invention. Various modifications and substitutions to the present invention will be apparent to those skilled in the art after reading the above description. Therefore, the scope of protection of the present invention should be defined by the appended claims.

Claims

1. A passive radar target return simulation system, characterized by, include: A radio frequency signal generator (20), a power divider (30), and an amplitude and phase control unit (40) are connected in sequence. The main control unit (10) is connected to the radio frequency signal generator (20) and the amplitude and phase control unit (40) respectively; The main control unit (10) is used to parse the received control commands to obtain the passive radar operating parameters and target parameters, and to convert the passive radar operating parameters and target parameters into the first control command and the second control command. The radio frequency signal generator (20) is used to generate a reference microwave signal according to the first control command; The power division unit (30) is used to divide the received reference microwave signal into N microwave signals, where N is a positive integer and N≥2; The amplitude and phase control unit (40) is used to receive the second control command, adjust the output amplitude and output phase of the N microwave signals respectively according to the second control command, and then combine the N microwave signals and output them. The amplitude and phase control unit (40) includes: amplitude and phase decoding circuit (401), N digitally controlled attenuators A1~An, N digitally controlled phase shifters B1~Bn and power combiner (402). The power amplifier (302) included in the power division unit (30) is connected to the N digitally controlled attenuators A1~An respectively, and the N digitally controlled attenuators A1~An and the N digitally controlled phase shifters B1~Bn are connected in a one-to-one correspondence. The N numerically controlled phase shifters B1~Bn are connected to the power combiner (402); The amplitude and phase decoding circuit (401) is used to parse the N-channel amplitude change command and the N-channel phase change command, obtain the phase and amplitude information of the N microwave signals, and convert them into amplitude control signals and phase control signals. The N numerically controlled attenuators A1~An are used to attenuate the power of the N microwave signals according to the amplitude control signal; The N numerically controlled phase shifters B1~Bn are used to shift the phase of the N microwave signals according to the phase control signal; The power combiner (402) is used to combine the N microwave signals after power attenuation and phase shifting into an echo signal carrying multi-target information for output; The operating bandwidth of the radio frequency signal generator (20), the numerically controlled attenuators A1~An and the numerically controlled phase shifters B1~Bn is greater than 10GHz. In the amplitude and phase control unit, a digitally controlled attenuator plus a digitally controlled phase shifter constitutes a channel, which simulates the generation of the echo signal of a single target.

2. The passive radar target echo simulation system as described in claim 1, characterized in that, The overall control unit (10) includes: a target echo modeling module (101), an amplitude and phase calibration module (102), and a communication control module (103). The communication control module (103) is connected to the target echo modeling module (101), the amplitude and phase calibration module (102), the radio frequency signal generator (20), and the amplitude and phase control unit (40), respectively. The communication control module (103) is used to receive externally input control commands, parse the control commands, obtain passive radar operating parameters and target parameters, and transmit them to the target echo modeling module (101). The target echo modeling module (101) constructs target echo simulation signals under different scenario models based on the passive radar operating parameters and target parameters, and transmits the target echo simulation signals back to the communication control module (103). The amplitude and phase calibration module (102) is used to calibrate the amplitude and phase of the N output channels of the amplitude and phase control unit (40) during the initialization phase of the passive radar target echo simulation system, and to test the initial amplitude and phase difference of the N output channels at different operating frequencies with the network analyzer, and record the calibration results. The communication control module (103) is also used to read the calibration result and the target echo analog signal, and convert them into the first control command and send them to the radio frequency signal generator (20) and convert them into the second control command and send them to the amplitude and phase control unit (40).

3. The passive radar target echo simulation system as described in claim 2, characterized in that, The first control command includes: pulse width change command, repetition rate change command, frequency change command, power change command, and signal on / off command; The second control command includes: N-channel amplitude change command and N-channel phase change command.

4. The passive radar target return analog system of claim 3, wherein, The radio frequency signal generator (20) sets the pulse width of the output reference microwave signal according to the pulse width change instruction; sets the pulse repetition period of the output reference microwave signal according to the repetition frequency change instruction; sets the frequency of the output reference microwave signal according to the frequency change instruction; sets the power of the output reference microwave signal according to the power change instruction; and sets whether to output the reference microwave signal according to the signal on / off instruction.

5. The passive radar target echo simulation system as described in claim 4, characterized in that, The power distribution unit (30) includes: a power divider (301) and a power amplifier (302) connected to each other. The power divider (301) is used to divide the reference microwave signal into the N microwave signals; The power amplifier (302) is used to output the N microwave signals after power compensation.

6. The passive radar target return analog system of claim 5, wherein, The main control unit (10) communicates with the radio frequency signal generator (20) and the amplitude and phase control unit (40) via a network cable.

7. The passive radar target echo simulation system as described in claim 6, characterized in that, The echo signal carrying multi-target information : wherein m represents the number of targets, , are the echo amplitude and the relative phase of the i first target, respectively, is the frequency of the target echo signal, and t denotes time.

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