CN-121995327-A - SAR radar interference method based on high-speed data transmission

CN121995327ACN 121995327 ACN121995327 ACN 121995327ACN-121995327-A

Abstract

The invention relates to the technical field of radar interference high-speed transmission, in particular to a SAR radar interference method based on high-speed data transmission, which comprises the following steps: receiving a radio frequency signal transmitted by an interfered synthetic aperture radar, performing down-conversion and analog-to-digital conversion on the radio frequency signal to obtain an original sampling data stream, transmitting the original sampling data stream to a programmable logic part through a high-speed serial interface, extracting pulse description words comprising pulse arrival time, pulse width, pulse repetition interval and carrier frequency, reconstructing a baseband waveform of a coherent interference signal in real time according to the pulse description words, performing digital up-conversion and digital pre-distortion processing on the baseband waveform to generate a target interference intermediate frequency digital signal, and transmitting the target interference intermediate frequency digital signal to the radio frequency transmission front end through the high-speed serial interface to finish digital-to-analog conversion and up-conversion, and then radiating the interference radio frequency signal. The method can reduce the delay of data transmission and signal processing, ensure interference signal relativity and improve the generation precision and processing instantaneity of the intermediate frequency signal.

Inventors

ZHU PENG
WANG ZHEN
LIU HAIFEI
JIANG HOUJUN
WANG SHUAI

Assignees

安徽星太宇科技有限公司

Dates

Publication Date: 20260508
Application Date: 20260409

Claims (10)

1. The SAR radar interference method based on high-speed data transmission is characterized by comprising the following steps: Receiving a radio frequency signal transmitted by an interfered synthetic aperture radar, and performing down-conversion and analog-to-digital conversion on the radio frequency signal by utilizing a radio frequency receiving front end to obtain an original sampling data stream; Transmitting the original sampled data stream to a programmable logic part through a high-speed serial interface, performing digital signal processing on the original sampled data stream in the programmable logic part, and extracting pulse descriptors, wherein the pulse descriptors comprise pulse arrival time, pulse width, pulse repetition interval and carrier frequency parameters; Reconstructing an interference signal baseband waveform related to the interfered synthetic aperture radar signal in real time in the programmable logic part according to the extracted pulse description word; In the programmable logic part, performing digital up-conversion and digital predistortion processing on the reconstructed interference signal baseband waveform to generate a target interference intermediate frequency digital signal; Transmitting the target interference intermediate frequency digital signal to a radio frequency transmitting front end through a high-speed serial interface, completing digital-to-analog conversion and up-conversion in the radio frequency transmitting front end, generating and radiating the target interference radio frequency signal to space.
2. The SAR radar interference method based on high speed data transmission of claim 1, wherein the digital signal processing of the original sampled data stream in the programmable logic section extracts pulse descriptors comprising: performing digital down-conversion and filtering processing on the original sampled data stream to obtain quadrature baseband signal data; Threshold detection is carried out on the orthogonal baseband signal data, starting and ending time points of each pulse are identified, and the pulse arrival time and the pulse width are obtained through calculation; Carrying out statistical analysis on a plurality of continuous pulse arrival times, calculating a time difference sequence of adjacent pulses, and extracting a stable time interval value from the time difference sequence as the pulse repetition interval; Performing spectrum analysis on the orthogonal baseband signal data corresponding to each identified pulse, searching a frequency point corresponding to a spectrum peak value, and determining the frequency point as the carrier frequency parameter; And packaging the pulse arrival time, the pulse width, the pulse repetition interval and the carrier frequency parameter obtained by each recognition calculation into a complete group of pulse description words, and storing the pulse description words into a first-in first-out queue of the programmable logic part.
3. The SAR radar interference method based on high-speed data transmission according to claim 2, wherein said reconstructing in real time in the programmable logic portion an interfering signal baseband waveform that is related to the interfered synthetic aperture radar signal from the extracted pulse descriptors comprises: reading the latest pulse description word from the first-in first-out queue; Generating a local carrier digital oscillation signal according to the carrier frequency parameter in the pulse description word; generating pulse gating signals with the same time width according to the pulse width in the pulse description word; multiplying the local carrier digital oscillation signal with the pulse gating signal to generate an unmodulated coherent pulse signal; Receiving a modulation parameter instruction from a processing system part, and applying amplitude modulation, phase modulation or frequency modulation to the unmodulated coherent pulse signal according to the modulation parameter instruction to form a modulated coherent pulse sequence; and repeatedly generating the modulated coherent pulse sequence by taking the pulse repetition interval in the pulse description word as a period to form continuous interference signal baseband waveforms.
4. The SAR radar interference method based on high-speed data transmission according to claim 3, wherein in the programmable logic section, the digital up-conversion and digital predistortion processing are performed on the reconstructed interference signal baseband waveform to generate a target interference intermediate frequency digital signal, comprising: Setting a fixed digital intermediate frequency to generate a local intermediate frequency digital carrier signal; carrying out digital mixing operation on the interference signal baseband waveform and the local intermediate frequency digital carrier signal, and moving the frequency spectrum of the interference signal baseband waveform to a frequency band taking the digital intermediate frequency as the center; Interpolation filtering is carried out on the digital sample points of the signals after the frequency mixing operation, and the sampling rate is increased to a preset radio frequency output sampling rate; Performing amplitude and phase reverse compensation operation on each sample point of the signal after the sampling rate is increased by searching a pre-generated radio frequency channel distortion compensation table, and completing the digital predistortion processing to obtain a predistorted digital signal; And carrying out peak clipping and digital filtering on the pre-distorted digital signal to finally generate the target interference intermediate frequency digital signal meeting the requirement of the input dynamic range of the radio frequency front end.
5. The SAR radar interference method based on high speed data transmission of claim 4, further comprising the step of running an interference policy scheduling algorithm in the processing system portion: in an embedded operating system running in the processing system part, maintaining a dynamically configurable interference strategy library, wherein the interference strategy library comprises a plurality of interference patterns and corresponding modulation parameter sets thereof; receiving threat target indication and interference pattern selection instructions from an external control interface; inquiring and screening the pulse description word set matched with the threat target from the first-in first-out queue according to the threat target indication; selecting an interference pattern from the interference strategy library according to the interference pattern selection instruction, and acquiring the modulation parameter set corresponding to the interference pattern; And issuing a modulation parameter set corresponding to the selected interference pattern to the programmable logic part as the modulation parameter instruction to control the generation of the interference signal baseband waveform.
6. The SAR radar interference method based on high-speed data transmission according to claim 5, further comprising the step of implementing interference waveform pre-storing and dynamic loading with a memory in the programmable logic section: Pre-storing long time base band interference waveform data of various complex modulations in the solid state disk connected with the programmable logic part; When the modulation parameter instruction issued by the processing system part indicates that a pre-stored waveform needs to be loaded, the programmable logic part initiates a direct memory access reading operation to the solid state disk through a hard core controller; Reading pre-stored waveform data with a specified length from a specified address of the solid state disk, and loading the pre-stored waveform data into a memory inside the programmable logic part; In the interference signal generation process, circularly reading the pre-stored waveform data from a memory in the programmable logic part to replace the interference signal baseband waveform generated in real time; And combining the circularly read pre-stored waveform data with real-time pulse synchronous information to enable the pre-stored waveform data to be output in a correct pulse period.
7. The SAR radar interference method based on high-speed data transmission of claim 6, further comprising the step of implementing time synchronization control of interference signal transmission and reception signal sampling in the programmable logic portion: Deploying a high precision timing counter in the programmable logic portion; Calibrating an initial phase of the high-precision timing counter with the pulse arrival time extracted from the received original sampled data stream so as to keep synchronization with a pulse repetition period of the interfered synthetic aperture radar; Controlling the time of transmitting the target interference intermediate frequency digital signal to the radio frequency transmitting front end by taking the value of the high-precision timing counter as a time reference, so that the radiated target interference radio frequency signal and the radar echo signal of expected interference have a set delay or advance relation in the time domain; continuously monitoring the pulse arrival time of a newly received pulse in the programmable logic part, and comparing the pulse arrival time with a predicted value of the high-precision timing counter; And when the comparison error exceeds a set threshold, dynamically adjusting the counting frequency of the high-precision timing counter or performing phase jump so as to maintain long-time stable synchronization with the interfered synthetic aperture radar.
8. The SAR radar interference method based on high-speed data transmission of claim 7, further comprising the step of implementing interference effect assessment and policy self-tuning in the processing system portion: in the processing system part, receiving interference effect evaluation data fed back by external electromagnetic environment monitoring equipment through a high-speed network interface; analyzing the interference effect evaluation data, and extracting an evaluation index representing the quality and the interference effectiveness of the interference signal; Comparing the evaluation index with a preset interference effectiveness threshold value, and judging whether the current interference strategy is effective or not; If the current interference strategy is judged to be invalid, the processing system part selects a standby interference pattern different from the current interference pattern from the master-slave interference strategy library; updating the modulation parameter set corresponding to the selected standby interference pattern into a new modulation parameter instruction, and sending the new modulation parameter instruction to the programmable logic part to adjust the radiated interference signal.
9. The high-speed data transmission-based SAR radar interference method according to claim 8, further comprising the step of implementing time-sharing interference for a plurality of concurrent threat targets in said programmable logic portion: In the programmable logic portion, maintaining a plurality of independent signal processing channels and waveform generation channels in parallel; each signal processing channel independently processes radio frequency signals from different threat targets and extracts the pulse description words corresponding to the radio frequency signals; The processing system part allocates different interference time slices for each threat target according to the threat priority; In the programmable logic part, according to the time slices distributed by the processing system part, controlling the corresponding waveform generation channels to be activated in the appointed time slices, and generating the target interference intermediate frequency digital signal aiming at the specific threat target; multiplexing the multiple target interference intermediate frequency digital signals generated in different time slices into one signal through a high-speed multiple-path selection switch, and transmitting the signal to a radio frequency transmitting front end for radiation.
10. The SAR radar interference method based on high-speed data transmission according to claim 9, wherein the interpolating filtering the digital samples of the mixed signal to increase the sampling rate to a preset rf output sampling rate, comprises: determining an interpolation ratio of an initial sampling rate and an integer multiple of the preset radio frequency output sampling rate; Inserting zero value sample points with the number equal to the integer multiple interpolation proportion minus one between every two adjacent digital sample points of the signals after the frequency mixing operation to form a zero value filled sequence; designing a low-pass filter with linear phase characteristics according to the preset radio frequency output sampling rate, wherein the cut-off frequency of the low-pass filter is less than or equal to half of the initial sampling rate; Performing convolution operation on the zero-value-filled sequence through the low-pass filter, and inhibiting a high-frequency mirror image frequency spectrum introduced by zero value insertion; performing gain compensation on the output sequence after convolution operation to ensure that the signal power is not attenuated due to the interpolation process; Intercepting a part containing effective data from the output sequence after gain compensation to obtain a digital signal sequence after interpolation and filtering; The sampling rate of the digital signal sequence after interpolation filtering is the preset radio frequency output sampling rate.

Description

SAR radar interference method based on high-speed data transmission Technical Field The invention relates to the technical field of radar interference high-speed transmission, in particular to a SAR radar interference method based on high-speed data transmission. Background In the conventional synthetic aperture radar interference technology, after down-conversion and analog-to-digital conversion, an original sampling data stream is mostly transmitted to a DSP, an ARM and other general processing devices through a general parallel interface, and the extraction operation of pulse description word parameters such as pulse arrival time, pulse width, pulse repetition interval, carrier frequency and the like is finished by depending on a back-end software program of a general processor. The baseband waveform reconstruction, digital up-conversion and predistortion processing links of the interference signals are respectively and independently executed in different hardware modules or devices, and the predistortion processing is mostly realized by adopting an analog circuit mode at a radio frequency transmitting end. The data transmission rate of the universal interface has a bottleneck, the pulse description word extraction of the software layer has time sequence lag, and the real-time processing rhythm of the high-speed SAR radar signal cannot be matched. The signal interaction among different modules can generate extra delay, interfere with the separate execution of waveform reconstruction, frequency conversion and predistortion links, easily cause signal phase deviation, have inherent limitations on the processing precision of analog predistortion, difficult guarantee the relativity of an interfering signal and an interfered SAR radar signal, and have insufficient output stability of an intermediate frequency digital signal. The original sampled data stream can not directly transmit the programmable logic part through the high-speed serial interface and complete the real-time extraction of pulse description words in the programmable logic part, the reconstruction of coherent interference baseband waveforms, the digital up-conversion and the digital predistortion processing can not be synchronously completed in the same programmable logic part, and the separation state of the existing transmission and processing architecture can not be adapted to the execution requirements of coherent interference of the high-speed SAR radar. Disclosure of Invention The invention aims to solve the defects in the prior art, and provides a SAR radar interference method based on high-speed data transmission. In order to achieve the purpose, the invention adopts the following technical scheme that the SAR radar interference method based on high-speed data transmission comprises the following steps: Receiving a radio frequency signal transmitted by an interfered synthetic aperture radar, and performing down-conversion and analog-to-digital conversion on the radio frequency signal by utilizing a radio frequency receiving front end to obtain an original sampling data stream; Transmitting the original sampled data stream to a programmable logic part through a high-speed serial interface, performing digital signal processing on the original sampled data stream in the programmable logic part, and extracting pulse descriptors, wherein the pulse descriptors comprise pulse arrival time, pulse width, pulse repetition interval and carrier frequency parameters; Reconstructing an interference signal baseband waveform related to the interfered synthetic aperture radar signal in real time in the programmable logic part according to the extracted pulse description word; In the programmable logic part, performing digital up-conversion and digital predistortion processing on the reconstructed interference signal baseband waveform to generate a target interference intermediate frequency digital signal; Transmitting the target interference intermediate frequency digital signal to a radio frequency transmitting front end through a high-speed serial interface, completing digital-to-analog conversion and up-conversion in the radio frequency transmitting front end, generating and radiating the target interference radio frequency signal to space. As a further aspect of the present invention, performing digital signal processing on the original sampled data stream in the programmable logic portion, extracting pulse descriptors, includes: performing digital down-conversion and filtering processing on the original sampled data stream to obtain quadrature baseband signal data; Threshold detection is carried out on the orthogonal baseband signal data, starting and ending time points of each pulse are identified, and the pulse arrival time and the pulse width are obtained through calculation; Carrying out statistical analysis on a plurality of continuous pulse arrival times, calculating a time difference sequence of adjacent pulses, and extracting a stable time