A low-altitude radar signal processing method, system, device and medium

Abstract

The application discloses a low-altitude radar signal processing method, system, device and medium, and particularly relates to the technical field of signal processing; the main points are as follows: a low-altitude radar measures four-channel calibration baseband complex signals based on a calibration source signal; one of the channels is taken as a phase reference channel, and the remaining three channels are sequentially taken as phase calibration channels; based on the orthogonal conjugate between the phase calibration channels and the phase reference channel, the phase calibration coefficients of each channel are calculated; one of the channels is taken as an amplitude reference channel, and the remaining three channels are taken as amplitude calibration channels; based on the ratio between the amplitude reference channel and the amplitude calibration channel, the amplitude calibration coefficients of each channel are obtained; the baseband complex signals are calibrated in amplitude and phase by using the phase calibration coefficients and the amplitude calibration coefficients, so that the calibrated baseband complex signals of each channel are obtained.

Description

Technical Field

[0001] This invention relates to the field of signal processing technology, and specifically to a low-altitude radar signal processing method, system, device, and medium. Background Technology

[0002] Low-altitude targets (UAVs, helicopters, small aircraft, etc.) are characterized by low altitude, slow speed, small radar cross section, strong clutter, and significant multipath effects, which place extremely high demands on the accuracy and anti-interference capabilities of radar detection. Multi-channel monopulse angle measurement system has become the mainstream solution for low-altitude radar due to its high-precision angle measurement advantage.

[0003] However, existing multi-channel radar detection technologies suffer from inherent amplitude / phase mismatch and asynchrony due to differences in components, temperature drift, and inconsistent link losses. This directly degrades the accuracy of sum and difference beamforming, resulting in significant angle measurement errors. Furthermore, the separate pulse compression and recombination of the four channels requires four sets of pulse compression processing resources (FFT / IFFT modules, multipliers, etc.), and subsequent sum and difference synthesis necessitates precise alignment of the compressed pulses from each channel, leading to complexity, high hardware resource consumption, and high power consumption. Modular architectures (FPGA+DSP separation) suffer from complex interfaces and high latency.

[0004] Therefore, the present invention aims to provide a low-altitude radar signal processing method, system, device, and medium to solve the aforementioned problems. Summary of the Invention

[0005] The technical problem this invention aims to solve is that existing multi-channel receiving systems suffer from inherent amplitude / phase mismatch and asynchrony due to differences in components, temperature drift, and inconsistent link losses. The goal is to provide a low-altitude radar signal processing method, system, device, and medium. By capturing the phase and amplitude deviations between four channels, the invention calculates the phase and amplitude calibration coefficients for each channel. Simultaneously, each channel uses these calibration coefficients to perform amplitude and phase calibration on the measured baseband complex signal, thereby solving the problem of poor channel consistency and improving radar signal quality. Furthermore, by performing a single measurement only on the radar antenna in the initial reference direction, a fixed and applicable calibration coefficient can be obtained, solving the problems of complex dynamic calibration, large storage requirements, instability under multipath conditions, and switching delays. This achieves simple and stable calibration, delay-free switching, and resistance to multipath jitter.

[0006] This invention is achieved through the following technical solution:

[0007] A low-altitude radar signal processing method, the method comprising:

[0008] A calibration source signal is transmitted to a low-altitude radar whose antenna beam direction is set to the initial reference direction. The low-altitude radar then measures the calibration baseband complex signal of four channels based on the calibration source signal.

[0009] Using one channel as the phase reference channel, the remaining three channels are set as phase calibration channels in sequence; based on the orthogonal conjugate between the baseband complex signals of each phase calibration channel and the phase reference channel, the phase calibration coefficient of each channel is calculated.

[0010] Using one of the channels as the amplitude reference channel, the remaining three channels are set as amplitude calibration channels in sequence; based on the ratio between the baseband complex signals calibrated by the amplitude reference channel and the amplitude calibration channel, the amplitude calibration coefficient of each channel is obtained;

[0011] By using the phase calibration coefficient and amplitude calibration coefficient of each channel, the measured baseband complex signal is calibrated in both phase and amplitude to obtain the calibrated baseband complex signal for each channel.

[0012] Furthermore, after obtaining the calibrated baseband complex signal for each channel, the method also includes:

[0013] Using pre-constructed signal superposition rules, the baseband complex signals after four-channel calibration are combined by sum and difference to obtain three signals; the three beam signals include sum beam signal, azimuth difference beam signal and elevation difference beam signal;

[0014] The three signals are subjected to frequency domain pulse compression processing, and the compressed three signals and wave control parameters are transmitted to an external DSP module.

[0015] Furthermore, the initial reference direction is such that the antenna beam has a horizontal angle of 0 and a pitch angle of 0.

[0016] Furthermore, based on the orthogonal conjugate between the calibration baseband complex signals of each phase calibration channel and the phase reference channel, the phase calibration coefficient of each channel is calculated, specifically as follows: In the formula, Indicates the first Phase calibration coefficient of the road channel, Indicates the number of sampling points. , These represent the in-phase and quadrature signals in the calibration baseband complex signal, respectively.

[0017] Furthermore, based on the ratio between the calibrated baseband complex signals of the amplitude reference channel and the amplitude calibration channel, the amplitude calibration coefficient for each channel is obtained, specifically: In the formula, Indicates the first The amplitude calibration coefficient of the road channel, , These represent the in-phase and quadrature signals in the calibration baseband complex signal, respectively.

[0018] Furthermore, using the phase calibration coefficient and amplitude calibration coefficient of each channel, the measured baseband complex signal is calibrated in both phase and amplitude to obtain the calibrated baseband complex signal for each channel, specifically: In the formula, This represents the calibrated baseband complex signal. Indicates the first Phase calibration coefficient of the road channel, Indicates the first The amplitude calibration coefficient of the road channel, , They represent the first The in-phase and quadrature signals in the baseband complex signal of the road channel.

[0019] The present invention also provides a low-altitude radar signal processing system, which is used in any of the above-described low-altitude radar signal processing methods, the system comprising:

[0020] The calibration signal measurement module is used to transmit calibration source signals to the low-altitude radar with the radar antenna beam direction set to the initial reference direction. The low-altitude radar measures the calibration baseband complex signals of four channels based on the calibration source signals.

[0021] The phase correction coefficient calculation module is used to take one channel as the phase reference channel and set the remaining three channels as phase calibration channels in sequence; based on the orthogonal conjugate between the baseband complex signals of the phase calibration channel and the phase reference channel, the phase calibration coefficient of each channel is calculated.

[0022] The amplitude calibration coefficient calculation module is used to take one channel as the amplitude reference channel and set the remaining three channels as amplitude calibration channels in sequence; based on the ratio between the calibration baseband complex signals of the amplitude reference channel and the amplitude calibration channel, the amplitude calibration coefficient of each channel is obtained.

[0023] The signal amplitude and phase calibration module is used to perform amplitude and phase calibration on the measured baseband complex signal using the phase calibration coefficient and amplitude calibration coefficient of each channel, so as to obtain the calibrated baseband complex signal of each channel.

[0024] The present invention also provides a computer device, including a system memory and a processor, wherein the system memory stores a computer program, and the processor executes the computer program to implement the steps of any of the methods described above.

[0025] The present invention also provides a computer-readable storage medium having a computer program stored thereon, wherein the computer program, when executed by a processor, implements the steps of any of the methods described above.

[0026] The present invention also provides a computer program product containing instructions that, when executed by a cluster of computer devices, cause the cluster of computer devices to perform the method described in any of the preceding claims.

[0027] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0028] 1. In this invention, by capturing the phase and amplitude deviations between four channels, the phase calibration coefficient and amplitude calibration coefficient of each channel are calculated. At the same time, the measured baseband complex signal is calibrated using the phase and amplitude calibration coefficients, thereby solving the problem of poor channel consistency and improving the radar signal quality. By performing a measurement only once on the radar antenna in the initial reference direction, a fixed and applicable calibration coefficient can be obtained, solving the problems of complex dynamic calibration, large storage requirements, instability under multipath conditions, and switching delay. This achieves the effects of simple and stable calibration, no switching delay, and resistance to multipath jitter.

[0029] 2. In this invention, by placing channel correction before sum-difference synthesis, only three sets of pulse compression resources are needed to ensure that the amplitude and phase of the four signals entering the sum-difference synthesis are consistent. This results in the synthesized sum-difference beams being phase-aligned in the target direction, significantly improving the accuracy of single-pulse angle measurement, especially suitable for low-altitude multipath environments. The horizontal and vertical angles of the antenna are directly controlled in real time by the FPGA. In this state, the echo data from the received antenna is processed. The pulse-compressed three-beam signals and the accompanying horizontal and vertical angles of the antenna are transmitted to the DSP in the same data frame for subsequent sum-difference angle measurement and other processing. In this way, the pulse-compressed data and the corresponding beam control parameters are matched without going through an external high-speed interface, resulting in no delay. This allows the DSP module to accurately complete subsequent sum-difference angle measurement and other functions, achieving high integration and low latency. This solves the problems of module separation, complex interfaces, and large delays in existing technologies. Attached Figure Description

[0030] To more clearly illustrate the technical solutions of the exemplary embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of the present invention and should not be considered as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort. In the drawings:

[0031] Figure 1 This is a schematic diagram of the structure of a low-altitude radar system in this embodiment;

[0032] Figure 2 This is a flowchart illustrating a low-altitude radar signal processing method in this embodiment;

[0033] Figure 3 This is a schematic diagram of the module connection of a low-altitude radar signal processing system in this embodiment;

[0034] Figure 4 This is a schematic diagram of the structure of a computer device in this embodiment. Detailed Implementation

[0035] The exemplary embodiments of this disclosure are described below with reference to the accompanying drawings, including various details of the embodiments to aid understanding, and should be considered merely exemplary. Therefore, those skilled in the art will recognize that various changes and modifications can be made to the embodiments described herein without departing from the scope of this disclosure. Similarly, for clarity and brevity, descriptions of well-known functions and structures are omitted in the following description.

[0036] In this disclosure, unless otherwise stated, the use of terms such as "first," "second," etc., to describe various elements is not intended to limit the positional, temporal, or importance relationships of these elements; such terms are merely used to distinguish one element from another. In some examples, the first element and the second element may refer to the same instance of that element, while in other cases, based on the context, they may refer to different instances.

[0037] The terminology used in the description of the various examples in this disclosure is for the purpose of describing particular examples only and is not intended to be limiting. Unless the context explicitly indicates otherwise, an element may be one or more unless the number of elements is specifically limited. Furthermore, the term "and / or" as used in this disclosure covers any one of the listed items and all possible combinations thereof.

[0038] Example 1

[0039] See Figure 1 , Figure 1 A schematic diagram of a low-altitude radar system is shown, which divides the antenna array into four antenna subarrays, each corresponding to one of the four channels. Each channel receives the radio frequency echo signal and processes it to obtain three signals, which are then transmitted to an external DSP module. (See also...) Figure 2 , Figure 2 A flowchart illustrating a low-altitude radar signal processing method is provided. This method is used for signal processing in the aforementioned low-altitude radar system, and includes:

[0040] S1: Transmit a calibration source signal to the low-altitude radar whose radar antenna beam direction is set to the initial reference direction. The low-altitude radar measures and obtains the four-channel calibration baseband complex signal based on the calibration source signal.

[0041] Specifically, the radar antenna beam direction of the low-altitude radar is initially set to an initial reference direction with a horizontal angle of 0 and an elevation angle of 0. Then, the signal source transmits a calibration source signal to the low-altitude radar. After each channel receives the radio frequency echo signal, it is down-converted to an intermediate frequency via analog down-conversion and then converted to a calibration baseband complex signal via digital down-conversion.

[0042] S2: Using one of the channels as the phase reference channel, the remaining three channels are sequentially set as phase calibration channels; based on the orthogonal conjugate between the baseband complex signals of the phase calibration channel and the phase reference channel, the phase calibration coefficient of each channel is calculated.

[0043] Specifically, for phase calibration of signals from different channels, one channel is first used as the phase reference channel, and the remaining three channels are sequentially set as phase calibration channels. Then, the orthogonal conjugate between the phase reference channel and the respective calibration baseband complex signals of the three phase calibration channels is calculated to obtain the phase deviation of each phase calibration channel. This phase deviation is used as the phase calibration coefficient. The phase deviation calculation function is as follows: In the formula, Indicates the first Phase calibration coefficient of the road channel, Indicates the number of sampling points. , These represent the in-phase and quadrature signals in the calibration baseband complex signal, respectively. Indicates the imaginary part. This represents the phase angle calculation function. Indicates phase calibration channel The calibration baseband complex signal, Indicates phase reference channel The calibration baseband complex signal.

[0044] S3: Using one of the channels as the amplitude reference channel, set the remaining three channels as amplitude calibration channels respectively; based on the ratio between the baseband complex signals calibrated by the amplitude reference channel and the amplitude calibration channel, obtain the amplitude calibration coefficient of each channel;

[0045] Specifically, for amplitude calibration of different channel signals, after acquiring a certain number of snapshots of baseband signal, the average signal amplitude is calculated. Using one of the signals as a reference, the amplitude of the other three signals is scaled up or down. The scaling factor is calculated by the ratio between the amplitude reference channel and the amplitude calibration channel's respective calibrated baseband complex signal. The amplitude calibration coefficient is calculated as follows: In the formula, Indicates the first The amplitude calibration coefficient of the road channel, , These represent the in-phase and quadrature signals in the calibration baseband complex signal, respectively.

[0046] S4: Using the phase calibration coefficient and amplitude calibration coefficient of each channel, the measured baseband complex signal is calibrated in both phase and amplitude to obtain the calibrated baseband complex signal for each channel.

[0047] Specifically, after obtaining the phase calibration coefficient and amplitude calibration coefficient, these two calibration coefficients are used as fixed calibration coefficients for the corresponding channels and stored. Then, after measuring the baseband complex signal, the signal is calibrated using the two calibration coefficients. The calibrated baseband complex signal is represented as follows: In the formula, This represents the calibrated baseband complex signal. Indicates the first Phase calibration coefficient of the road channel, Indicates the first The amplitude calibration coefficient of the road channel, , They represent the first The in-phase and quadrature signals in the baseband complex signal of the road channel.

[0048] It should also be noted that, in this embodiment, after obtaining the calibrated baseband complex signal for each channel, the method further includes:

[0049] Using pre-constructed signal superposition rules, the baseband complex signals after four-channel calibration are combined by sum and difference to obtain three signals; the three beam signals include sum beam signal, azimuth difference beam signal and elevation difference beam signal;

[0050] The three signals are subjected to frequency domain pulse compression processing, and the compressed three signals and wave control parameters are transmitted to an external DSP module.

[0051] Specifically, after obtaining four signals, three signals will be generated using a two-stage adder according to a preset signal superposition rule, as follows: , , In the formula, These represent the baseband complex signals after calibration for the four channels; Indicates beam signal, Indicates azimuth difference beam signal, Indicates pitch difference beam signal;

[0052] Then, frequency domain pulse compression is performed on the sum beam signal, azimuth difference beam signal, and elevation difference beam signal respectively, and the compressed three signals and wave control parameters are transmitted to the external DSP module.

[0053] It should be noted that in existing technologies, beam control is achieved through DSP control and signal processing is handled by FPGA. Signal processing and corresponding beam control parameters are separated into two modules, FPGA and DSP, resulting in a lack of real-time matching between the processed signal data and the corresponding beam control parameters. Furthermore, complex interface protocols are required for communication, leading to issues such as module separation, complex interfaces, and high latency. In contrast, this technical solution directly controls the antenna's horizontal and vertical angles in real-time via the FPGA. In this state, the echo data from the antenna is received and processed. The pulse-compressed three-channel beam signals, along with the accompanying antenna horizontal and vertical angles, are transmitted to the DSP within the same data frame for subsequent sum and difference angle measurement and other processing. This allows for accurate matching of the pulse-compressed data and corresponding beam control parameters without the need for an external high-speed interface, eliminating latency and enabling the DSP module to accurately complete subsequent sum and difference angle measurement functions, achieving high integration and low latency.

[0054] To verify the technical effectiveness of this solution, tests were conducted on the four signals in this solution. The test results are shown in Table 1 below:

[0055] Table 1

[0056]

[0057] According to the research by Wang Yue and Lü Ming in "Research on Channel Consistency Correction Method of Single Pulse Radar System", when the amplitude error is <1.4 dB and the phase error is <0.27 rad, the channel mismatch will significantly affect the angle measurement accuracy. After amplitude and phase correction, the angle measurement accuracy is significantly improved, meeting the system design requirements.

[0058] Meanwhile, dynamic calibration requires real-time calculation of calibration coefficients, resulting in large storage requirements. Furthermore, the calibration coefficients exhibit significant jitter in multipath environments, and there is a delay during mode switching. Therefore, a comparative analysis of the stability of the calibration coefficients and the mode switching delay was also conducted. The results are shown in Table 2 below.

[0059] Table 2

[0060]

[0061] In addition, a comparative analysis of signal processing delay was conducted, and the results are shown in Table 3 below:

[0062] Table 3

[0063]

[0064] The above-mentioned optimization example of a multi-channel high-speed signal processing system based on FPGA shows that, through architecture optimization (parallel processing, pipeline design), the processing latency can be reduced from 120 μs to 40 μs, a reduction of 66.7%, and the throughput can be increased by 50%.

[0065] Example 2

[0066] See Figure 3 The present invention also provides a low-altitude radar signal processing system, which is used in any of the above-described low-altitude radar signal processing methods, the system comprising:

[0067] The calibration signal measurement module 100 is used to transmit calibration source signals to the low-altitude radar whose radar antenna beam direction is set to the initial reference direction. The low-altitude radar measures and obtains four-channel calibration baseband complex signals based on the calibration source signals.

[0068] The phase correction coefficient calculation module 200 is used to take one channel as the phase reference channel and set the remaining three channels as phase calibration channels in sequence; based on the orthogonal conjugate between the baseband complex signals of the phase calibration channel and the phase reference channel, the phase calibration coefficient of each channel is calculated.

[0069] The amplitude calibration coefficient calculation module 300 is used to take one channel as the amplitude reference channel and set the remaining three channels as amplitude calibration channels respectively; based on the ratio between the calibration baseband complex signals of the amplitude reference channel and the amplitude calibration channels, the amplitude calibration coefficient of each channel is obtained.

[0070] The signal amplitude and phase calibration module 400 is used to perform amplitude and phase calibration on the measured baseband complex signal using the phase calibration coefficient and amplitude calibration coefficient of each channel, so as to obtain the calibrated baseband complex signal of each channel.

[0071] It should be noted that the modules in the system of Embodiment 2 correspond to the steps in the method of Embodiment 1. The steps in the method of Embodiment 1 have been described in detail in Embodiment 1, and the module content in the system will not be described in detail in this Embodiment 2.

[0072] Example 3

[0073] See Figure 4 This embodiment also provides a computer device, including a system memory 1005 and a processor 1001. The system memory 1005 stores a computer program, and the processor 1001 executes the computer program to implement the steps of any of the methods described above.

[0074] It should be noted that the processor 1001 is used to execute the steps in the above method embodiments according to the instructions in the program code. Alternatively, when the processor 1001 executes the computer program, it implements the functions of each module / unit in the above system / device embodiments.

[0075] Specifically, in this embodiment, the computer program can be divided into one or more modules / units, which are stored in the system memory 1005 and executed by the processor 1001 to complete this application. The one or more modules / units can be a series of computer program instruction segments capable of performing specific functions, which describe the execution process of the computer program in the terminal device.

[0076] The terminal device can be a desktop computer, laptop, handheld computer, or cloud server, etc. The terminal device may include, but is not limited to, a processor 1001 and a system memory 1005. Those skilled in the art will understand that this does not constitute a limitation on the terminal device; it may include more or fewer components than shown in the figures, or a combination of certain components, or different components. For example, the terminal device may also include an input / output device 1003, a network access device 1002, a bus 1006, etc.

[0077] The processor 1001 can be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor can be a microprocessor or any conventional processor.

[0078] System memory 1005 can be an internal storage unit of the terminal device, such as a hard drive or RAM. System memory 1005 can also be a storage device 1004 of the terminal device, such as an external hard drive, SmartMedia Card (SMC), Secure Digital (SD) card, or FlashCard. Furthermore, system memory 1005 can include both internal storage units and storage device 1004. System memory 1005 is used to store computer programs and other programs and data required by the terminal device. System memory 1005 can also be used to temporarily store data that has been output or will be output.

[0079] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the systems and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0080] Example 4

[0081] This embodiment provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of any of the methods described above.

[0082] The computer-readable storage medium may be, for example, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, device, or any combination thereof. More specific examples of computer-readable storage media (a non-exhaustive list) include: an electrical connection having one or more wires, a portable computer disk, a hard disk, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM), registers, hard disks, optical fibers, compact disc read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination thereof, or any other form of computer-readable storage medium in the art.

[0083] An exemplary storage medium is coupled to a processor, enabling the processor to read information from and write information to the storage medium. Of course, the storage medium can also be a component of the processor. The processor and storage medium can reside within an application-specific integrated circuit (ASIC). In embodiments of the invention, the computer-readable storage medium can be any tangible medium containing or storing a program that can be used by or in conjunction with an instruction execution system, system, or device.

[0084] Example 5

[0085] This embodiment also provides a computer program product containing instructions that, when executed by a cluster of computer devices, cause the cluster of computer devices to perform the method described in Embodiment 1.

[0086] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A low-altitude radar signal processing method, characterized in that, The methods include: A calibration source signal is transmitted to a low-altitude radar whose antenna beam direction is set to the initial reference direction. The low-altitude radar then measures the calibration baseband complex signal of four channels based on the calibration source signal. Using one of the channels as the phase reference channel, the remaining three channels are set as phase calibration channels in sequence. The phase calibration coefficient of each channel is calculated based on the orthogonal conjugate between the calibration baseband complex signals of each phase calibration channel and the phase reference channel. Using one of the channels as the amplitude reference channel, the remaining three channels are set as amplitude calibration channels in sequence. The amplitude calibration coefficient for each channel is obtained based on the ratio between the calibrated baseband complex signals of the amplitude reference channel and the amplitude calibration channel. By using the phase calibration coefficient and amplitude calibration coefficient of each channel, the measured baseband complex signal is calibrated in both phase and amplitude to obtain the calibrated baseband complex signal for each channel.

2. The low-altitude radar signal processing method according to claim 1, characterized in that, After obtaining the calibrated baseband complex signal for each channel, the method further includes: Using pre-constructed signal superposition rules, the baseband complex signals after four-channel calibration are combined by sum and difference to obtain three signals; the three beam signals include sum beam signal, azimuth difference beam signal and elevation difference beam signal; The three signals are subjected to frequency domain pulse compression processing, and the compressed three signals and wave control parameters are transmitted to an external DSP module.

3. The low-altitude radar signal processing method according to claim 1, characterized in that, The initial reference direction is when the antenna beam has a horizontal angle of 0 and a pitch angle of 0.

4. The low-altitude radar signal processing method according to claim 1, characterized in that, Based on the orthogonal conjugate between the calibration baseband complex signals of each phase calibration channel and the phase reference channel, the phase calibration coefficients of each channel are calculated as follows: In the formula, Indicates the first Phase calibration coefficient of the road channel, Indicates the number of sampling points. , These represent the in-phase and quadrature signals in the calibration baseband complex signal, respectively.

5. The low-altitude radar signal processing method according to claim 1, characterized in that, Based on the ratio between the calibrated baseband complex signals of the amplitude reference channel and the amplitude calibration channel, the amplitude calibration coefficient of each channel is obtained, specifically: In the formula, Indicates the first The amplitude calibration coefficient of the road channel, , These represent the in-phase and quadrature signals in the calibration baseband complex signal, respectively.

6. The low-altitude radar signal processing method according to claim 1, characterized in that, Using the phase and amplitude calibration coefficients of each channel, the measured baseband complex signal is calibrated in both phase and amplitude to obtain the calibrated baseband complex signal for each channel, as follows: In the formula, This represents the calibrated baseband complex signal. Indicates the first Phase calibration coefficient of the road channel, Indicates the first The amplitude calibration coefficient of the road channel, , They represent the first The in-phase and quadrature signals in the baseband complex signal of the road channel.

7. A low-altitude radar signal processing system, characterized in that, This system is used in a low-altitude radar signal processing method according to any one of claims 1-6, the system comprising: The calibration signal measurement module is used to transmit calibration source signals to the low-altitude radar with the radar antenna beam direction set to the initial reference direction. The low-altitude radar measures the calibration baseband complex signals of four channels based on the calibration source signals. The phase correction coefficient calculation module is used to take one channel as the phase reference channel and set the remaining three channels as phase calibration channels in sequence; based on the orthogonal conjugate between the calibration baseband complex signals of each phase calibration channel and the phase reference channel, the phase calibration coefficient of each channel is calculated. The amplitude calibration coefficient calculation module is used to take one channel as the amplitude reference channel and set the remaining three channels as amplitude calibration channels in sequence; based on the ratio between the calibration baseband complex signals of the amplitude reference channel and the amplitude calibration channel, the amplitude calibration coefficient of each channel is obtained. The signal amplitude and phase calibration module is used to perform amplitude and phase calibration on the measured baseband complex signal using the phase calibration coefficient and amplitude calibration coefficient of each channel, so as to obtain the calibrated baseband complex signal of each channel.

8. A computer device comprising a system memory and a processor, wherein the system memory stores a computer program, characterized in that, When the processor executes the computer program, it implements the steps of the method according to any one of claims 1 to 6.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by a processor, it implements the steps of the method described in any one of claims 1 to 6.

10. A computer program product containing instructions, characterized in that, When the instructions are executed by a cluster of computer devices, the cluster of computer devices causes the cluster of computer devices to perform the method as described in any one of claims 1 to 6.

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