A method and system for adaptive down-conversion of arbitrary parameter radar signals

Abstract

The present application relates to a method and system for adaptive down-conversion of arbitrary parameter radar signals. The method comprises: obtaining the original signal of any data channel in the phased array radar signal acquisition system, caching the original signal, and detecting the original signal to determine the current signal frequency; when the judgment signal actually arrives, generating a DDS output signal according to the current signal frequency through a signal generator; after the DDS output signal is generated, waiting for a preset clock cycle, reading the IQ signal cached in the cache module, mixing the IQ signal and the DDS output signal through a complex multiplier, and down-converting the original signal to a baseband signal in real time. The present invention accurately down-converts the collected arbitrary parameter signal to a baseband signal, greatly reducing the data rate of the system transmission and reducing the hardware limitations; in addition, the activation of the threshold value and the adaptation to any signal significantly improve the adaptability of the present invention to complex electromagnetic environments.

Description

Technical Field

[0001] The present application relates to the technical field of radar signal processing, and in particular to a method and system for adaptive down-conversion of arbitrary parameter radar signals based on a variable threshold. Background Art

[0002] With the development of modern radars, the requirements for technical indicators such as multi-target, multi-function, and strong anti-interference have been put forward. Phased array radar has received great attention and development due to its advantages in these aspects. Phased array radar is a radar array composed of a large number of identical radiating units, each of which is independently controlled by wave control and phase shifters in phase and amplitude. In order to increase power and obtain higher performance, phased array radars usually use a large number of radiating units, and finally form multiple data channels to interact with digital transceiver systems. Faced with the increasing sampling bit width and number of channels, how to effectively reduce the data rate to ensure that the hardware system can quickly and accurately collect, store, and process radar signals has become an important issue in modern radar signal processing.

[0003] When encountering the above problems, the traditional solution is usually to choose to "window" the data - intermittent transmission; or to set the corresponding signal down-conversion in the acquisition system in advance for a specific electromagnetic environment. The former of these two methods will cause some data loss; the latter lacks flexibility and universality and cannot adapt to the complex electromagnetic environment in reality. In order to ensure fast and accurate radar signal processing, it is necessary to explore a method to effectively reduce the data rate. Summary of the invention

[0004] Based on this, it is necessary to provide a method and system for adaptive down-conversion of radar signals with arbitrary parameters that can improve the adaptability of the radar signal down-conversion method in order to solve the above technical problems.

[0005] A method for adaptive down-conversion of an arbitrary parameter radar signal, the method comprising:

[0006] Acquire the original signal of any data channel in the phased array radar signal acquisition system, and cache the original signal; the original signal includes two IQ signals;

[0007] Performing fast Fourier transform on the two IQ signals respectively and calculating the square sum to obtain a complex signal of the original signal, and determining the current signal frequency according to the peak value of the complex signal;

[0008] When the peak value is greater than a preset threshold, the current signal is determined to be a valid signal, and when it is determined to be a valid signal for a preset number of consecutive times, a DDS output signal is generated according to the current signal frequency by a signal generator;

[0009] After the DDS output signal is generated, wait for a preset clock cycle, read the IQ signal cached in the cache module, mix the IQ signal and the DDS output signal through a complex multiplier, and down-convert the original signal to a baseband signal in real time.

[0010] In one of the embodiments, the method further includes: acquiring an I signal and a Q signal of the two IQ signals;

[0011] Perform N1-point fast Fourier transform on the I signal and the Q signal respectively and then calculate the square sum to be I 2 +Q 2 ; The value of N1 is the sampling rate of the phased array radar signal acquisition system.

[0012] In one of the embodiments, the method further includes: determining a current signal frequency according to an X coordinate corresponding to a peak value of the complex signal.

[0013] In one of the embodiments, the present invention further comprises: when the peak value is greater than a preset threshold, determining that the current signal is a valid signal;

[0014] Taking N1 sampling points as one round, collect multiple rounds of original signals and generate corresponding complex signals for multiple rounds;

[0015] When the signal is determined to be valid for a preset number of times, a pulse start signal is generated;

[0016] When the pulse start signal is detected, a DDS output signal is generated according to the current signal frequency by a signal generator.

[0017] In one of the embodiments, the method further comprises: according to the current signal frequency f1;

[0018] Send the configuration parameters corresponding to -f1 to the signal generator IP core;

[0019] A DDS output signal is generated by the signal generator according to the configuration parameters.

[0020] In one of the embodiments, it further includes: after the DDS output signal is generated, after waiting for a preset clock cycle and completing the parameter reloading of the signal generator IP core, issuing a read instruction to the cache module;

[0021] After receiving the read instruction through the cache module, the IQ signal cached in the cache module is read in sequence; wherein the reading of the IQ signal is synchronized with the output of the DDS output signal.

[0022] In one of the embodiments, it further includes: waiting for a preset clock cycle after the DDS output signal is generated, and reading the IQ signal cached in the cache module; wherein the cache time length corresponding to the IQ signal cached in the cache module is greater than the time length consumed to generate the DDS output signal.

[0023] In one of the embodiments, the preset threshold is set according to different radiation source parameters.

[0024] An arbitrary parameter radar signal adaptive down-conversion system, the system comprising:

[0025] The signal detection module is used to obtain the original signal of any data channel in the phased array radar signal acquisition system; the original signal includes two IQ signals; the two IQ signals are subjected to fast Fourier transformation and then the square sum is calculated to obtain the complex signal of the original signal, and the current signal frequency is determined according to the peak value of the complex signal; when the peak value is greater than a preset threshold, the current signal is determined to be a valid signal, and when it is determined to be a valid signal for a preset number of consecutive times, it is determined that a valid pulse has arrived;

[0026] The DDS module is used to generate a DDS output signal according to the current signal frequency through a signal generator when a valid pulse arrives;

[0027] The cache module is used to cache the original signal, and wait for a preset clock cycle after the DDS output signal is generated to read the cached IQ signal;

[0028] The mixing module is used to mix the IQ signal and the DDS output signal through a complex multiplier, and down-convert the original signal to a baseband signal in real time.

[0029] In one of the embodiments, the system further includes an ADC acquisition module; the ADC acquisition module is used to convert the analog signal received by the phased array radar into a digital original signal.

[0030] A computer device comprises a memory and a processor, wherein the memory stores a computer program, and when the processor executes the computer program, the following steps are implemented:

[0031] Acquire the original signal of any data channel in the phased array radar signal acquisition system, and cache the original signal; the original signal includes two IQ signals;

[0032] Performing fast Fourier transform on the two IQ signals respectively and calculating the square sum to obtain a complex signal of the original signal, and determining the current signal frequency according to the peak value of the complex signal;

[0033] When the peak value is greater than a preset threshold, the current signal is determined to be a valid signal, and when it is determined to be a valid signal for a preset number of consecutive times, a DDS output signal is generated according to the current signal frequency by a signal generator;

[0034] After the DDS output signal is generated, wait for a preset clock cycle, read the IQ signal cached in the cache module, mix the IQ signal and the DDS output signal through a complex multiplier, and down-convert the original signal to a baseband signal in real time.

[0035] A computer-readable storage medium stores a computer program, which, when executed by a processor, implements the following steps:

[0036] Acquire the original signal of any data channel in the phased array radar signal acquisition system, and cache the original signal; the original signal includes two IQ signals;

[0037] Performing fast Fourier transform on the two IQ signals respectively and calculating the square sum to obtain a complex signal of the original signal, and determining the current signal frequency according to the peak value of the complex signal;

[0038] When the peak value is greater than a preset threshold, the current signal is determined to be a valid signal, and when it is determined to be a valid signal for a preset number of consecutive times, a DDS output signal is generated according to the current signal frequency by a signal generator;

[0039] After the DDS output signal is generated, wait for a preset clock cycle, read the IQ signal cached in the cache module, mix the IQ signal and the DDS output signal through a complex multiplier, and down-convert the original signal to a baseband signal in real time.

[0040] The above-mentioned arbitrary parameter radar signal adaptive down-conversion method and system obtains the original signal of any data channel in the phased array radar signal acquisition system, caches the original signal, and performs fast Fourier transformation on the two IQ signals in the original signal while caching, and then calculates the square sum to obtain the complex signal of the original signal, and determines the current signal frequency according to the peak value of the complex signal; when the peak value is greater than the preset threshold, the current signal is determined to be a valid signal, and when it is determined to be a valid signal for a preset number of consecutive times, a DDS output signal is generated according to the current signal frequency through a signal generator; after the DDS output signal is generated, a preset clock cycle is waited, the IQ signal cached in the cache module is read, and the IQ signal and the DDS output signal are mixed by a complex multiplier, and the original signal is down-converted to a baseband signal in real time. The present invention accurately down-converts the collected arbitrary parameter signal to a baseband signal, greatly reducing the data rate of system transmission and reducing the hardware limitation; in addition, the activation of the threshold value and the adaptation to arbitrary signals significantly improve the adaptability of the present invention to complex electromagnetic environments. The present invention plays an important role in promoting the development of software-based radar platforms towards multiple array elements and high data volume. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 This is a diagram of an application scenario of a method for adaptive down-conversion of a radar signal with arbitrary parameters in one embodiment;

[0042] Figure 2 1 is a flow chart of a method for adaptive down-conversion of a radar signal with arbitrary parameters in one embodiment;

[0043] Figure 3 It is a flowchart of a method for adaptive down-conversion of a radar signal with arbitrary parameters in a specific embodiment;

[0044] Figure 4 It is a time-frequency diagram of a 1.32 GHz center frequency LFM (Linear Frequency Modulation) signal in a specific embodiment that does not adopt the present invention;

[0045] Figure 5 It is a time-frequency diagram of a 1.32 GHz center frequency LFM signal using the present invention in a specific embodiment;

[0046] Figure 6 It is a time-frequency diagram of a 1.34 GHz center frequency LFM signal using the present invention in a specific embodiment;

[0047] Figure 7 It is a time-frequency diagram of a 1.37 GHz center frequency LFM signal using the present invention in a specific embodiment;

[0048] Figure 8FIG. 4 is a diagram showing the internal structure of a computer device in one embodiment. DETAILED DESCRIPTION

[0049] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0050] The method for adaptive down-conversion of arbitrary parameter radar signals provided in this application can be applied to Figure 1 In the application environment shown in the figure, after the ADC collects the signal, the signal is detected by the signal detection module. When a valid signal is detected, its frequency value is calculated, and the corresponding configuration parameters are fed back to the DDS module to generate a corresponding signal, which is used to mix with the original signal cached in the cache module through the mixing module, so as to down-convert the original signal to the baseband.

[0051] In one embodiment, Figure 2 As shown, a method for adaptive down-conversion of an arbitrary parameter radar signal is provided, comprising the following steps:

[0052] Step 202: Acquire the original signal of any data channel in the phased array radar signal acquisition system and cache the original signal.

[0053] The original signal includes two IQ signals, where I is the real part of the signal and Q is the imaginary part of the signal.

[0054] Phased array radar is a radar array composed of a large number of identical radiating units, each of which is independently controlled by wave control and phase shifters in terms of phase and amplitude. In order to increase power and obtain higher performance, phased array radars usually use a large number of radiating units, ultimately forming multiple data channels for data exchange with digital transceiver systems.

[0055] Step 204, perform fast Fourier transform on the two IQ signals respectively and calculate the square sum to obtain the complex signal of the original signal, and determine the current signal frequency according to the peak value of the complex signal.

[0056] Fast Fourier Transform converts time domain signals to frequency domain.

[0057] Step 206, when the peak value is greater than the preset threshold, the current signal is determined to be a valid signal. When it is determined to be a valid signal for a preset number of consecutive times, a DDS (Direct Digital Synthesis) output signal is generated according to the current signal frequency by a signal generator.

[0058] According to the actual signal strength, this method sets an amplitude threshold value A. Due to the problems of electromagnetic interference and transmission accuracy in the actual use environment, only when multiple pulses exceeding the threshold are detected continuously, it is considered that a valid pulse has arrived. At this time, a pulse start signal is generated. When the rising edge of this pulse start signal is detected, the generation of DDS coefficients begins, allowing the DDS output to move the signal to the required frequency of the baseband.

[0059] By setting corresponding threshold values ​​according to different radiation source parameters, the effective signal frequency reaching the threshold can be accurately identified, it has good universality and can adapt to different electromagnetic environments.

[0060] Step 208, after the DDS output signal is generated, wait for a preset clock cycle, read the IQ signal cached in the cache module, mix the IQ signal and the DDS output signal through a complex multiplier, and down-convert the original signal to a baseband signal in real time.

[0061] Adaptive down-conversion for arbitrary frequency signals can move complex signal spectra, including agile LFM signals, to the baseband, greatly reducing the data rate of system transmission and alleviating hardware limitations.

[0062] In the above-mentioned adaptive down-conversion method for arbitrary parameter radar signals, the original signal of any data channel in the phased array radar signal acquisition system is obtained, the original signal is cached, and the two IQ signals in the original signal are fast Fourier transformed and then the square sum is calculated while caching to obtain the complex signal of the original signal, and the current signal frequency is determined according to the peak value of the complex signal; when the peak value is greater than the preset threshold, the current signal is determined to be a valid signal, and when it is determined to be a valid signal for a preset number of consecutive times, a DDS output signal is generated according to the current signal frequency by a signal generator; after the DDS output signal is generated, a preset clock cycle is waited, the IQ signal cached in the cache module is read, and the IQ signal and the DDS output signal are mixed by a complex multiplier, and the original signal is down-converted to a baseband signal in real time. The present invention accurately down-converts the collected arbitrary parameter signal to a baseband signal, greatly reducing the data rate of system transmission and reducing the hardware limitation; in addition, the activation of the threshold value and the adaptation to any signal significantly improve the adaptability of the present invention to complex electromagnetic environments. The present invention plays an important role in promoting the development of software-based radar platforms towards multiple array elements and high data volume.

[0063] In one embodiment, the method further includes: obtaining an I signal and a Q signal from two IQ signals; performing N1-point fast Fourier transform on the I signal and the Q signal respectively and calculating the square sum to be I 2 +Q 2 ; The value of N1 is the sampling rate of the phased array radar signal acquisition system.

[0064] In one of the embodiments, the method further includes: determining the current signal frequency according to the X coordinate corresponding to the peak value of the complex signal.

[0065] In one of the embodiments, it also includes: when the peak value is greater than a preset threshold, determining that the current signal is a valid signal; taking N1 sampling points as one round, collecting multiple rounds of original signals, and generating multiple rounds of corresponding complex signals; when it is determined to be a valid signal for a preset number of consecutive times, generating a pulse start signal; when the pulse start signal is detected, generating a DDS output signal according to the current signal frequency through a signal generator.

[0066] In one of the embodiments, the method further includes: according to the current signal frequency f1; sending configuration parameters corresponding to -f1 to the signal generator IP (Intellectual Property) core; and generating a DDS output signal according to the configuration parameters by the signal generator.

[0067] In one of the embodiments, it also includes: waiting for a preset clock cycle after the DDS output signal is generated, and after completing the parameter reloading of the signal generator IP core, issuing a read instruction to the cache module; after receiving the read instruction through the cache module, sequentially reading the IQ signal cached in the cache module; wherein the reading of the IQ signal is synchronized with the output of the DDS output signal.

[0068] In one of the embodiments, it further includes: waiting for a preset clock cycle after the DDS output signal is generated, and reading the IQ signal cached in the cache module; wherein the cache time length corresponding to the IQ signal cached in the cache module is greater than the time length consumed to generate the DDS output signal.

[0069] In one of the embodiments, the preset threshold is set according to different radiation source parameters.

[0070] It should be understood that although Figure 2 The steps in the flowchart are shown in sequence as indicated by the arrows, but these steps are not necessarily executed in the order indicated by the arrows. Unless otherwise specified in this document, there is no strict order restriction for the execution of these steps, and these steps can be executed in other orders. Moreover, Figure 2 At least part of the steps may include multiple sub-steps or multiple stages. These sub-steps or stages are not necessarily executed at the same time, but can be executed at different times. The execution order of these sub-steps or stages is not necessarily sequential, but can be executed in turn or alternately with other steps or at least part of the sub-steps or stages of other steps.

[0071] In one embodiment, Figure 1As shown, a system for adaptive down-conversion of arbitrary parameter radar signals is provided, comprising: a signal detection module, a DDS module, a buffer module and a mixing module;

[0072] The signal detection module is used to obtain the original signal of any data channel in the phased array radar signal acquisition system; the original signal includes two IQ signals; the two IQ signals are subjected to fast Fourier transform respectively and then the square sum is calculated to obtain the complex signal of the original signal, and the current signal frequency is determined according to the peak value of the complex signal; when the peak value is greater than the preset threshold, the current signal is determined to be a valid signal, and when it is determined to be a valid signal for a preset number of consecutive times, it is determined that a valid pulse has arrived;

[0073] The DDS module is used to generate a DDS output signal according to the current signal frequency through a signal generator when a valid pulse arrives;

[0074] The cache module is used to cache the original signal and wait for a preset clock cycle after the DDS output signal is generated to read the cached IQ signal;

[0075] The mixing module is used to mix the IQ signal and the DDS output signal through a complex multiplier, and down-convert the original signal to a baseband signal in real time.

[0076] In one of the embodiments, the system further includes an ADC (Analog to Digital Converter) acquisition module; the ADC acquisition module is used to convert the analog signal received by the phased array radar into a digital original signal.

[0077] In a specific embodiment, Figure 3 As shown, a method for adaptive down-conversion of an arbitrary parameter radar signal is provided, comprising:

[0078] S1: Radiation source signal detection and original signal buffering

[0079] This step consists of two simultaneous branches, codenamed S1.1 and S1.2.

[0080] S1.1 Radiation source signal detection

[0081] S1.1.1 The radar signal acquisition system usually has multiple data channels. Select the two IQ signals of one of the channels and perform N1-point FFT (the value of N1 should be as close to the sampling rate as possible).

[0082] S1.1.2 Calculate the sum of squares of the above two sets of results (I 2 +Q 2 ), the complex signal of this channel is obtained, and the signal frequency F at this time can be obtained according to the X coordinate corresponding to its peak value.

[0083] S1.1.3 According to the strength of the effective signal in the actual application scenario, this method sets an amplitude threshold value A1. Only when the peak value A2 calculated by one round of the complex signal in S1.1.2 (i.e., N1 sampling points) is greater than A1, the signal at this time is judged to be a valid signal that reaches the threshold, and the signal frequency f1 corresponding to the first round of crossing the threshold is recorded.

[0084] S1.1.4 Due to electromagnetic interference and transmission accuracy issues in the actual use environment, the signal is considered to have arrived only when there are valid signals reaching the threshold in n1 consecutive rounds (the value of n1 is related to the oscillation of the actual signal).

[0085] S1.1.5 In order to move the original signal spectrum to the baseband, according to the first round of signal frequency f1 that passes the threshold recorded in S1.1.3, the configuration parameters corresponding to -f1 are sent to the DDS IP core, so that it generates a signal with a frequency of -f1.

[0086] Perform N1-point FFT on the two IQ signals of one channel (the value of N1 should be as close to the sampling rate as possible), and then calculate the square sum of the results (I 2 +Q 2 ) to obtain the complex signal of this channel. According to the strength of the actual signal, this method sets an amplitude threshold value A. Due to the problems of electromagnetic interference and transmission accuracy in the actual use environment, only when N2 pulses that exceed the threshold are detected continuously, it is considered that a valid pulse has arrived. At this time, a pulse start signal is generated. When the rising edge of this pulse start signal is detected, the generation of the DDS coefficient begins, allowing the DDS output to move the signal to the required frequency of the baseband. After the DDS coefficient is generated, wait for 4 beats (to allow DDS to complete the coefficient reload) and let the cache FIFO start reading.

[0087] S1.2 Raw signal buffer

[0088] Since the signal detection and DDS parameter reload in S1.1 take a certain amount of time, in order to synchronize the original signal with the signal output by DDS, the original signal must be cached. It should be noted that the cache capacity must be greater than the total time consumed by S1.1, otherwise part of the original signal will be lost and cannot be fully collected.

[0089] S2: Synchronous signal reading

[0090] Once different signal frequencies are detected in S1.1, the parameters of the DDS IP core are reloaded after N3 clock cycles. At this time, the system sends a read instruction to the cache module to read out the original signal sampled by the ADC and enter the hardware system in sequence to ensure that the DDS output signal is synchronized with the original signal.

[0091] S3: Down-conversion of the original signal

[0092] Since the original signal contains two channels of IQ information, a complex multiplier is needed to mix the IQ information and the DDS output signal, and down-convert the original signal to a baseband signal in real time, effectively reducing the transmission data rate.

[0093] The advantages of the present invention are verified by actual measured data.

[0094] The actual test is based on Xilinx's ZCU111 development board, which integrates the RFSoC IP core. A -1.3GHz NCO (Numerically Controlled Oscillator) is set inside the IP core for down-conversion. The system front end uses a signal source to input an LFM signal to a channel of the board. The parameters are shown in the table. The signal collected by the board is finally stored in the disk array, and Matlab is used to analyze the signal.

[0095] Center frequency 1.32GHz Pulse Width 10us bandwidth 10M Duty Cycle 50％ Sampling rate 130MHz

[0096] Figure 4 This is the signal time-frequency diagram corresponding to when the adaptive down-conversion method of the present invention is not used. The horizontal axis represents time and the vertical axis represents signal frequency. Because 128-point FFT calculation is used when drawing the time-frequency diagram, each scale on the vertical axis represents 130 / 128≈1MHz, and the vertical axis scale 64 represents the 0MHz frequency point. It can be seen that the center frequency of the signal in the time-frequency diagram is near scale 44, and the original signal is mixed with the -1.3GHz signal to become a signal with a center frequency of 20M, and the center frequencies corresponding to the two are consistent. At this time, the LFM signal requires a sampling rate of at least 50MHz (2*f max ), and the minimum transmission data rate of this channel is: 50MHz*16bit=100MB.

[0097] Figure 5 This is the signal time-frequency diagram corresponding to the adaptive down-conversion method of the present invention. The center frequency of the signal is located near 0MHz, and the 1MHz error comes from the fact that this experiment is only designed to be 1M accurate, so it is a normal phenomenon and is completely acceptable in actual use. At this time, the LFM signal requires at least a 10MHz sampling rate (2*f max ), and the minimum transmission data rate of this channel is: 10MHz*16bit=20MB. Compared with the 100MB data rate when the present invention is not used, its data rate is only 1 / 5, and it is far away from the 1.3GHz center frequency, and the data rate decreases more significantly, which is enough to prove that the present invention can effectively reduce the transmission data rate while ensuring sampling accuracy.

[0098] In order to demonstrate the adaptive detection of any frequency by the present invention, two groups of signals with different center frequencies were added to the experiment. Figure 6 1.34GHz, Figure 7 It is a time-frequency diagram corresponding to 1.37 GHz. It can be seen that when the signal frequency changes, the adaptive down-conversion method of the present invention can still move the original signal spectrum to the baseband.

[0099] For the specific definition of the adaptive down-conversion device for arbitrary parameter radar signals, please refer to the definition of the adaptive down-conversion method for arbitrary parameter radar signals in the above text, which will not be repeated here. Each module in the above-mentioned adaptive down-conversion device for arbitrary parameter radar signals can be implemented in whole or in part by software, hardware and a combination thereof. The above-mentioned modules can be embedded in or independent of the processor in the computer device in the form of hardware, or can be stored in the memory in the computer device in the form of software, so that the processor can call and execute the operations corresponding to the above modules.

[0100] In one embodiment, a computer device is provided. The computer device may be a terminal, and its internal structure diagram may be as follows: Figure 8 As shown. The computer device includes a processor, a memory, a network interface, a display screen and an input device connected through a system bus. Among them, the processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system and a computer program. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The network interface of the computer device is used to communicate with an external terminal through a network connection. When the computer program is executed by the processor, a method for adaptive down-conversion of an arbitrary parameter radar signal is implemented. The display screen of the computer device can be a liquid crystal display screen or an electronic ink display screen, and the input device of the computer device can be a touch layer covered on the display screen, or a key, trackball or touchpad set on the computer device housing, or an external keyboard, touchpad or mouse, etc.

[0101] Those skilled in the art will understand that Figure 8 The structure shown in the figure is only a block diagram of a part of the structure related to the solution of the present application, and does not constitute a limitation on the computer device to which the solution of the present application is applied. The specific computer device may include more or fewer components than those shown in the figure, or combine certain components, or have a different arrangement of components.

[0102] In one embodiment, a computer device is provided, including a memory and a processor, wherein the memory stores a computer program, and the processor implements the steps in the above method embodiment when executing the computer program.

[0103] In one embodiment, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, the steps in the above method embodiment are implemented.

[0104] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to memory, storage, database or other media used in the embodiments provided in this application can include non-volatile and / or volatile memory. Non-volatile memory can include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM) or flash memory. Volatile memory can include random access memory (RAM) or external cache memory. As an illustration and not limitation, RAM is available in many forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link (Synchlink) DRAM (SLDRAM), memory bus (Rambus) direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM).

[0105] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0106] The above-mentioned embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the attached claims.

Claims

1. A method for adaptive down-conversion of arbitrary parameter radar signals, characterized in that: The method comprises: Acquire the original signal of any data channel in the phased array radar signal acquisition system, and cache the original signal; the original signal includes two IQ signals; Performing fast Fourier transform on the two IQ signals respectively and calculating the square sum to obtain a complex signal of the original signal, and determining the current signal frequency according to the peak value of the complex signal; When the peak value is greater than a preset threshold, the current signal is determined to be a valid signal, and when it is determined to be a valid signal for a preset number of consecutive times, a DDS output signal is generated according to the current signal frequency by a signal generator; After the DDS output signal is generated, wait for a preset clock cycle, read the IQ signal cached in the cache module, mix the IQ signal and the DDS output signal through a complex multiplier, and down-convert the original signal to a baseband signal in real time.

2. The method according to claim 1, characterized in that: Performing fast Fourier transform on the two IQ signals respectively and then calculating the square sum, including: Acquire an I signal and a Q signal from the two IQ signals; Perform N1-point fast Fourier transform on the I signal and the Q signal respectively and then calculate the square sum to be I 2 +Q 2 ; The value of N1 is the sampling rate of the phased array radar signal acquisition system.

3. The method according to claim 2, characterized in that Determining the current signal frequency according to the peak value of the complex signal includes: The current signal frequency is determined according to the X coordinate corresponding to the peak value of the complex signal.

4. The method according to claim 3, characterized in that When the peak value is greater than a preset threshold, the current signal is determined to be a valid signal. When it is determined to be a valid signal for a preset number of consecutive times, a DDS output signal is generated according to the current signal frequency by a signal generator, including: When the peak value is greater than a preset threshold, the current signal is determined to be a valid signal; Taking N1 sampling points as one round, collect multiple rounds of original signals and generate corresponding complex signals for multiple rounds; When the signal is determined to be valid for a preset number of times, a pulse start signal is generated; When the pulse start signal is detected, a DDS output signal is generated according to the current signal frequency by a signal generator.

5. The method according to claim 4, characterized in that Generating a DDS output signal according to the current signal frequency by a signal generator, including: According to the current signal frequency f1; Send the configuration parameters corresponding to -f1 to the signal generator IP core; A DDS output signal is generated by the signal generator according to the configuration parameters.

6. The method according to claim 5, characterized in that After the DDS output signal is generated, wait for a preset clock cycle and read the IQ signal cached in the cache module, including: After the DDS output signal is generated, it waits for the preset clock cycle, completes the parameter reloading of the signal generator IP core, and then issues a read instruction to the cache module; After receiving the read instruction through the cache module, the IQ signal cached in the cache module is read in sequence; wherein the reading of the IQ signal is synchronized with the output of the DDS output signal.

7. The method according to claim 6, characterized in that After the DDS output signal is generated, wait for a preset clock cycle and read the IQ signal cached in the cache module, including: After the DDS output signal is generated, wait for a preset clock cycle and read the IQ signal cached in the cache module; wherein the cache time length corresponding to the IQ signal cached in the cache module is greater than the time length consumed to generate the DDS output signal.

8. The method according to any one of claims 1 to 7, characterized in that: The preset threshold is set according to different radiation source parameters.

9. An adaptive down-conversion system for arbitrary parameter radar signals, characterized in that: The system comprises: a signal detection module, a DDS module, a buffer module and a mixing module; The signal detection module is used to obtain the original signal of any data channel in the phased array radar signal acquisition system; the original signal includes two IQ signals; the two IQ signals are subjected to fast Fourier transformation and then the square sum is calculated to obtain the complex signal of the original signal, and the current signal frequency is determined according to the peak value of the complex signal; when the peak value is greater than a preset threshold, the current signal is determined to be a valid signal, and when it is determined to be a valid signal for a preset number of consecutive times, it is determined that a valid pulse has arrived; The DDS module is used to generate a DDS output signal according to the current signal frequency through a signal generator when a valid pulse arrives; The cache module is used to cache the original signal, and wait for a preset clock cycle after the DDS output signal is generated to read the cached IQ signal; The mixing module is used to mix the IQ signal and the DDS output signal through a complex multiplier, and down-convert the original signal to a baseband signal in real time.

10. The system according to claim 9, characterized in that The system also includes an ADC acquisition module; The ADC acquisition module is used to convert the analog signal received by the phased array radar into the digital original signal.

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