Interference target detection method and device, radar equipment and storage medium

Abstract

The invention provides an interference target detection method and device, radar equipment and a storage medium, and the method is used for detecting an interference target generated by an interference radar to the radar, and comprises the steps: configuring a first waveform and a second waveform to be transmitted by the radar; obtaining a distance Doppler spectrum matrix of the first waveform and the second waveform; obtaining a distance index and a Doppler index of a target according to the distance Doppler spectrum matrix; acquiring amplitudes of the first waveform and the second waveform according to the distance index and the Doppler index; and judging whether the target is a real target or an interference target according to the amplitudes of the first waveform and the second waveform. In a parallel interference scene, a real target and a false target caused by interference are effectively distinguished so that a false alarm rate is reduced.

Description

Technical Field

[0001] The present application relates to the field of radar target detection technology, and in particular to an interference target detection method, device, radar equipment and storage medium. Background Art

[0002] Millimeter-wave radars usually transmit linear frequency modulated continuous wave signals. When two radars work at the same time and transmit signals in the same frequency band, interference will occur. This interference can be divided into two types: parallel interference and cross interference. Parallel interference means that the modulation frequencies of the two radars are consistent. In this case, false targets will be generated, thereby increasing the false alarm rate. Cross interference means that the modulation frequencies of the two radars are inconsistent. In this case, the noise floor will be increased, thereby increasing the false alarm rate. Summary of the invention

[0003] The present application provides an interference target detection method, device, radar equipment and storage medium to solve the problem of effectively reducing the false alarm rate in the case of parallel interference.

[0004] In a first aspect, the present application provides an interference target detection method for detecting an interference target generated by an interference radar to the radar, the interference target detection method comprising:

[0005] Configuring a first waveform and a second waveform to be transmitted by the radar;

[0006] Acquire the range Doppler spectrum matrix of the first waveform and the second waveform;

[0007] According to the range-Doppler spectrum matrix, obtaining a range index and a Doppler index of the target;

[0008] Acquire the amplitudes of the first waveform and the second waveform according to the distance index and the Doppler index;

[0009] According to the amplitudes of the first waveform and the second waveform, it is determined whether the target is a real target or an interference target.

[0010] In one embodiment of the present application, configuring the first waveform and the second waveform to be transmitted by the radar includes:

[0011] Transmit a certain number of chirps for each frame signal, and divide the certain number of chirps into two groups with odd and even indexes, corresponding to the first waveform and the second waveform respectively, so that each group of waveforms has its own number of chirps;

[0012] A phase shifter is used to shift each transmitting antenna by a preset frequency to achieve DDMA coding of the waveform.

[0013] In an embodiment of the present application, acquiring the range Doppler spectrum matrix of the first waveform and the second waveform includes:

[0014] Performing a discrete Fourier transform of the intermediate frequency signals of the first waveform and the second waveform in fast time dimension and slow time dimension to obtain two sets of range Doppler spectrum matrices;

[0015] Processing the range Doppler spectrum matrix to equally divide it into a number of sub-intervals in the Doppler dimension;

[0016] A modulo operation is performed on the range-Doppler spectrum matrix in each subinterval and the matrix is ​​added together to obtain a detection matrix.

[0017] In an embodiment of the present application, acquiring the range index and Doppler index of the target according to the range-Doppler spectrum matrix includes:

[0018] Performing target detection on the detection matrix of the first waveform using a constant false alarm detection algorithm;

[0019] Using a preset decoding method and combining the range Doppler spectrum matrix of the second waveform to perform transmit antenna separation to achieve DDMA decoding;

[0020] Based on the information obtained by separating the transmitting antennas, a range index and a Doppler index of the target are determined.

[0021] In an embodiment of the present application, acquiring the amplitudes of the first waveform and the second waveform according to the distance index and the Doppler index includes:

[0022] According to the acquired range index and Doppler index of the target, locate the target on the range-Doppler spectrum matrix of the first waveform, and obtain its amplitude;

[0023] According to the acquired range index and Doppler index of the target, the target is located on the range-Doppler spectrum matrix of the second waveform, and its amplitude is acquired.

[0024] In an embodiment of the present application, judging whether the target is a real target or an interference target according to the amplitudes of the first waveform and the second waveform includes:

[0025] comparing the amplitude difference corresponding to the first waveform and the second waveform;

[0026] If the amplitude difference meets the set threshold condition, the target is determined to be a real target;

[0027] Otherwise, the target is determined to be an interference target caused by parallel interference.

[0028] In an embodiment of the present application, configuring the first waveform and the second waveform to be transmitted by the radar further includes:

[0029] For the second waveform, one or more transmitting antennas are turned off, and for the first waveform, all transmitting antennas are kept turned on;

[0030] Determine a code length according to the number of transmit antennas, and assign a code bit to each transmit antenna for each of the first waveform and the second waveform;

[0031] A coding feature is matched with each transmitting antenna to form a set of transmitting antenna coding sequences of a first waveform and a second waveform, wherein the coding feature uses binary to represent whether the transmitting antenna is in an on state and whether the transmitting antenna is in an off state.

[0032] In a second aspect, the present application further provides an interference target detection device for detecting interference targets generated by an interference radar to the radar, the interference target detection device comprising:

[0033] A waveform configuration module, used to configure the first waveform and the second waveform to be transmitted by the radar;

[0034] A Doppler spectrum acquisition module, used to acquire the range Doppler spectrum matrix of the first waveform and the second waveform;

[0035] A target index acquisition module, used to acquire the range index and Doppler index of the target according to the range-Doppler spectrum matrix;

[0036] an amplitude acquisition module, configured to acquire the amplitudes of the first waveform and the second waveform according to the distance index and the Doppler index;

[0037] The target judgment module is used to judge whether the target is a real target or an interference target according to the amplitudes of the first waveform and the second waveform.

[0038] In a third aspect, the present application also provides a radar device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the program, the steps of the interference target detection method as described in the first aspect are implemented.

[0039] In a fourth aspect, the present application further provides a non-transitory computer-readable storage medium having a computer program stored thereon, and when the computer program is executed by a processor, the steps of the interference target detection method as described in any one of the first aspects are implemented.

[0040] The interference target detection method, device, radar equipment and storage medium provided by the present application are designed to enhance the distinction between false targets and real targets in parallel interference scenarios by designing the characteristics of the first waveform and the second waveform, thereby reducing the false alarm rate. In addition, for the range Doppler spectrum matrix extracted from the first waveform and the second waveform, combined with the range index and Doppler index of the target, a more in-depth Doppler spectrum analysis is performed, and the extracted amplitude information is used to effectively distinguish between real targets and false targets (i.e., interference targets) caused by interference, thereby reducing the false alarm rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] In order to more clearly illustrate the technical solutions in the present application or the prior art, a brief introduction will be given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0042] Figure 1 It is a flowchart of the interference target detection method provided by this application;

[0043] Figure 2a is the RD diagram of waveform 1 in TDMA mode of embodiment 1 of the present application;

[0044] Figure 2b This is the RD diagram of waveform 2 in TDMA mode in Example 1 of the present application;

[0045] Figure 3a It is an index diagram of waveform 1 target 1 in TDMA mode of embodiment 1 of the present application;

[0046] Figure 3b It is an index diagram of waveform 2 target 1 in TDMA mode of embodiment 1 of the present application;

[0047] Figure 4a It is an index diagram of waveform 1 target 2 in TDMA mode of embodiment 1 of the present application;

[0048] Figure 4b is an index diagram of waveform 2 target 2 in TDMA mode of embodiment 1 of the present application;

[0049] Figure 5a It is the RD diagram of waveform 1 in DDMA mode of embodiment 2 of the present application;

[0050] Figure 5b It is the RD diagram of waveform 2 in DDMA mode of embodiment 2 of the present application;

[0051] Figure 6a It is an index diagram of waveform 1 target 1 in DDMA mode of embodiment 2 of the present application;

[0052] Figure 6b is an index diagram of waveform 2 target 1 in DDMA mode of embodiment 2 of the present application;

[0053] Figure 7a It is an index diagram of waveform 1 target 2 in DDMA mode of embodiment 2 of the present application;

[0054] Figure 7b is an index map of waveform 2 target 2 in DDMA mode of embodiment 2 of the present application;

[0055] Figure 8a It is the RD diagram of waveform 1 in DDMA mode of embodiment 3 of the present application;

[0056] Figure 8b It is the RD diagram of waveform 2 in DDMA mode of embodiment 3 of the present application;

[0057] Figure 9a It is an index diagram of waveform 1 target 1 in DDMA mode of embodiment 3 of the present application;

[0058] Figure 9b It is an index map of waveform 2 target 1 in DDMA mode of embodiment 3 of the present application;

[0059] Fig.10a It is an index diagram of waveform 1 target 2 in DDMA mode of embodiment 3 of the present application;

[0060] Fig.10b It is an index map of waveform 2 target 2 in DDMA mode of embodiment 3 of the present application;

[0061] Fig.11a It is an index diagram of waveform 1 target 3 in DDMA mode of embodiment 3 of the present application;

[0062] Fig.11b It is an index map of waveform 2 target 3 in DDMA mode of embodiment 3 of the present application;

[0063] Fig.12 A schematic diagram of the structure of an interference target detection device provided in the present application. DETAILED DESCRIPTION

[0064] In order to make the purpose, technical solutions and advantages of this application clearer, the technical solutions in this application will be clearly and completely described below in conjunction with the drawings in this application. Obviously, the described embodiments are part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0065] The terms "first", "second", etc. in the specification and claims of this application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the terms used in this way can be interchanged where appropriate, so that the embodiments described herein can be implemented in an order other than that illustrated or described herein.

[0066] When two radar systems operate simultaneously and transmit signals with similar frequencies, they will interfere with each other. If the transmitted signal of one radar is received by another radar, the receiving radar will try to process the signal through steps such as mixing, filtering and sampling. However, even after these processes, the frequency of the interfering signal will be within the intermediate frequency bandwidth of the receiving radar. Interference includes parallel interference and cross interference.

[0067] Parallel interference refers to two or more radar systems using the same modulation frequency and operating in the same frequency band, interfering with each other and generating false targets, thereby increasing the false alarm rate.

[0068] Cross-interference refers to two or more radar systems using different modulation rates and operating in the same frequency band. When the signal of one radar leaks into the receiving channel of other radars, it will cause the background noise to increase, resulting in an increase in the missed alarm rate.

[0069] In order to solve the problem of effectively reducing the false alarm rate under the parallel interference situation, the present application provides a kind of interference target detection method, device, radar equipment and storage medium, the method firstly designs waveform characteristics, makes the characteristics of real target and interference target different in the received first waveform and second waveform even in the parallel interference scene, thereby enhancing their distinguishability. Then, for the range Doppler spectrum matrix extracted from the first waveform and the second waveform, in combination with the range index and Doppler index of the target, a more in-depth Doppler spectrum analysis is performed. At the same time, the extracted amplitude information is used to effectively distinguish the real target and the false target caused by the interference, thereby reducing the false alarm rate.

[0070] That is to say, in parallel interference scenarios, it is difficult to distinguish between real targets and false targets caused by interference, thereby increasing the false alarm rate. The interference target detection method provided by the present application enhances the distinction between real targets and interference targets in the received signal by designing the characteristics of the transmission waveform, and effectively reduces the false alarm rate in parallel interference scenarios by combining Doppler spectrum analysis and amplitude information.

[0071] Combine the following Figure 1-Figure 12 The invention describes the interference target detection method, device, radar equipment and storage medium of the present application.

[0072] Please refer to Figure 1 , Figure 1The figure is a flow chart of the interference target detection method provided by the present application. A method for detecting interference targets, used to detect interference targets generated by an interference radar to the present radar, the method for detecting interference targets comprising:

[0073] Step 110, configuring the first waveform and the second waveform to be transmitted by the radar.

[0074] The first waveform and the second waveform are two different waveforms transmitted by the radar system, which are configured to separate the real target signal from the interference signal.

[0075] Step 120: Obtain the range Doppler spectrum matrix of the first waveform and the second waveform.

[0076] That is, the signals received after transmitting the first waveform and the second waveform are processed to obtain their spectrum matrices in the distance dimension and the Doppler velocity dimension. The range-Doppler spectrum matrix can be used to describe the distribution of targets in terms of distance and velocity. In a radar system, the distance of a target object is determined by measuring the round-trip time of the signal, while the velocity of the target object is calculated by the Doppler frequency shift. The range-Doppler spectrum matrix can provide the signal energy distribution at different distances and different velocities.

[0077] Step 130: Obtain the range index and Doppler index of the target according to the range-Doppler spectrum matrix.

[0078] That is to say, the distance information and Doppler velocity information of the target can be extracted from the range-Doppler spectrum matrix. The range index refers to the index of the target position in the distance dimension. In a radar system, the distance between the target and the radar system can be determined by measuring the round-trip time of the signal. The range index represents the position information of the target in the distance dimension, usually in units of range units or range resolution. The Doppler index refers to the index of the target velocity in the Doppler velocity dimension. The Doppler effect refers to the phenomenon that when a target moves at different speeds relative to the radar system, the frequency of the received signal changes. The Doppler index represents the motion state of the target in the velocity dimension, usually in units of Doppler frequency.

[0079] Step 140: Obtain the amplitudes of the first waveform and the second waveform according to the distance index and the Doppler index.

[0080] That is to say, according to the obtained distance index and Doppler index information, the corresponding amplitude information can be extracted from the signals received by the first waveform and the second waveform. Amplitude refers to the amplitude or strength of the signal, also known as the voltage, power or energy of the signal. In the radar system, the amplitude reflects the strength of the received signal at a certain moment. By obtaining the amplitude of the first waveform and the second waveform, the intensity distribution of the signal can be understood, so as to further analyze the characteristics and properties of the target.

[0081] Step 150: judging whether the target is a real target or an interference target according to the amplitudes of the first waveform and the second waveform.

[0082] That is to say, the acquired amplitude information is used for target identification to distinguish between real targets and interference targets. Real targets refer to real objects sensed by the radar system, such as aircraft, vehicles, ships, etc. False targets refer to false alarm signals caused by external interference or system errors, such as terrain reflection, atmospheric interference, clutter interference, etc. By comparing the amplitude information received by the first waveform and the second waveform, the target identification can be judged. Real targets usually have relatively stable signal characteristics, and their amplitude changes will not be too drastic; while false targets show characteristics such as unstable amplitude and obvious fluctuations.

[0083] The above steps 110 to 150 are described in detail below.

[0084] Exemplarily, in the above step 110, configuring the first waveform and the second waveform to be transmitted by the radar includes:

[0085] Step 111, a certain number of chirps are transmitted for each frame signal, and the certain number of chirps are divided into two groups with odd and even indexes, corresponding to the first waveform and the second waveform respectively, so that each group of waveforms has its own number of chirps.

[0086] Specifically, in a radar system, a certain number (which can be a pre-set number) of chirp signals need to be transmitted per frame signal. Chirp signal is a pulse signal with linear frequency modulation, which is very common in distance and speed measurement. The transmitted chirps are divided into two groups according to their index positions in the sequence, namely, an odd index group and an even index group. This division is conducive to subsequent signal processing and encoding. The chirps of the odd index group are assigned to the first waveform, and the chirps of the even index group are assigned to the second waveform. In this way, the first waveform and the second waveform will receive different chirp signal sequences during the signal transmission process. In this way, in a dual waveform radar system, different chirp signals can be effectively distinguished and processed to achieve more accurate and efficient signal processing and improve the performance and accuracy of the radar system.

[0087] For example, suppose the radar has N Tx Transmitting antennas, namely Tx 1~N Tx Each frame of signal transmits N chirps (N is an even number), and divides the N chirps into two groups with odd and even indexes, called the first waveform and the second waveform, and each group of waveforms has N / 2 chirps.

[0088] Step 112, using a phase shifter to shift each transmitting antenna by a preset frequency offset to implement DDMA coding of the waveform.

[0089] Specifically, when configuring a dual waveform radar system, a specific frequency offset is applied to each transmit antenna using a phase shifter in order to implement DDMA (Doppler Diversity Multiple Access) encoding of the waveform. A phase shifter is a device used to change the phase of a signal. By moving the phase of a signal, a frequency offset or phase shift can be achieved, thereby changing the characteristics of the signal. Applying a specific frequency offset to each transmit antenna means adding a preset frequency modulation to the signal of each transmit antenna.

[0090] DDMA coding is a radar signal-based multi-processing adaptive technology used to distinguish and process multiple signal sources in a radar system. By applying a specific frequency offset to each transmitting antenna, the signal emitted by each transmitting antenna can have unique characteristics in the spectrum, thereby realizing DDMA coding of the waveform.

[0091] Specifically, to realize the DDMA waveform, a phase shifter may be used at the front end of the transmitting antenna to shift each transmitting antenna to a specific frequency to realize DDMA coding.

[0092] For example, for the transmitting antenna k, the phase shift applied by its phase shifter is ω k ,in

[0093]

[0094] In the formula, f(N Tx ) is a constant related to the number of transmitting antennas, let Δω=2π / f(N Tx ), the phase shift configuration of the transmitting antenna of the first waveform and the second waveform is as follows:

[0095] Table 1: Transmit antenna phase shifter configuration for the first waveform

[0096]

[0097]

[0098] Table 2: Transmit antenna phase shifter configuration for the second waveform

[0099]

[0100] Specifically, the steps for transmitting antenna encoding include:

[0101] (1) For the second waveform, one or several transmitting antennas are turned off, while for the first waveform, all transmitting antennas are kept turned on.

[0102] That is, during the processing of the second waveform, a portion of the transmitting antennas can be selectively turned off. When processing the first waveform, all transmitting antennas are kept turned on. This means that during the processing of the first waveform, the system keeps all transmitting antennas in working state, that is, all transmitting antennas are sending signals. Through such operations, different transmitting antenna configurations can be implemented for different waveforms in the dual waveform radar system.

[0103] (2) The code length is determined according to the number of transmitting antennas, and a code bit is assigned to each transmitting antenna for the first waveform and the second waveform respectively.

[0104] The code length refers to the number of bits used to represent the state of each transmit antenna. The code length is determined based on the number of transmit antennas used in the system. Generally, the code length is associated with the number of transmit antennas. For the first waveform and the second waveform, the system specifies a code bit for each transmit antenna. This means that the system assigns a specific code bit to each transmit antenna to represent the state of the transmit antenna. This coding method allows different transmit antennas to be distinguished and the coded information to be used in signal processing and data analysis.

[0105] For example, for the above example, the encoding length is N Tx , corresponding to Tx 1~N respectively Tx The encoding method uses binary representation, where a coding bit of 1 indicates that the transmitting antenna is in the on state, and a coding bit of 0 indicates that the transmitting antenna is in the off state. At the same time, the transmitting antenna index set corresponding to 0 in the transmitting antenna code is recorded as set K, and all transmitting antenna index sets are recorded as set T.

[0106] (3) The coding feature is matched with each transmitting antenna to form a set of transmitting antenna coding sequences of the first waveform and the second waveform, wherein the coding feature uses binary to represent whether the transmitting antenna is in the on state and the transmitting antenna is in the off state.

[0107] Specifically, for each transmitting antenna, the system assigns a binary value to it to indicate the state of the transmitting antenna, that is, on or off. According to the state of each transmitting antenna, the system encodes it into a binary value, and then combines these binary values ​​into a set of coding sequences, corresponding to the transmitting antenna states of the first waveform and the second waveform, respectively.

[0108] For example, the dual waveform radar system includes four transmitting antennas, namely transmitting antenna 1 to transmitting antenna 4. The coding sequence of the first waveform is 1111, that is, all transmitting antennas are turned on; the coding sequence of the second waveform is 1110, that is, transmitting antenna 4 is turned off.

[0109] It should be noted that the first waveform and the second waveform configured in the present application mean that the radar system can transmit radar signals with these two waveforms. Moreover, the radar system can send these two waveforms alternately. In other words, the radar system will not use the same waveform continuously, but will send two different waveforms alternately at a certain time interval.

[0110] After receiving the echo signal, the radar system performs the above steps 120 to 150 on the intermediate frequency signals of the two waveforms respectively.

[0111] Exemplarily, in the above step 120, obtaining the range Doppler spectrum matrix of the first waveform and the second waveform includes:

[0112] Step 121 , performing a discrete Fourier transform of the intermediate frequency signals of the first waveform and the second waveform in fast time dimensions and slow time dimensions to obtain two sets of range Doppler spectrum matrices.

[0113] That is to say, the change of the signal in the fast time dimension is analyzed spectrally to understand the components of the signal at different frequencies, which can help determine the position of the target in the distance direction. The change of the signal in the slow time dimension is analyzed spectrally to understand the characteristics of the target in the Doppler frequency, that is, the speed information of the target. Through the above processing, two sets of matrices can be obtained, which are the spectrum matrices of the first waveform and the second waveform in the distance and Doppler frequency. These spectrum matrices provide information about the distance and speed of the target.

[0114] For example, when processing Doppler signals, the number of Doppler Fourier transform points is N. d After the first waveform and the second waveform are transformed in the Doppler dimension, two spectrum matrices, namely RD (range-Doppler) matrices, are obtained. These two spectrum matrices contain information about the range and Doppler frequency of the signal received by the radar. Then, the two RD matrices are modulo-operated to obtain the RD graph.

[0115] Step 122: Process the range-Doppler spectrum matrix and divide it into a number of sub-intervals in the Doppler dimension.

[0116] In the dimension of Doppler frequency, the spectrum matrix is ​​divided into several sub-intervals, which can better analyze the characteristics of target signals in different Doppler frequency ranges. For example, the two RD matrices are equally divided into f(N Tx ) sub-intervals, each sub-interval has a Doppler dimension length of N d / f(N Tx ).

[0117] Step 123 , performing a modulo operation on the range Doppler spectrum matrix in each sub-interval and adding them together to obtain a detection matrix.

[0118] After the spectrum matrix is ​​divided into several sub-intervals in the Doppler dimension, a range Doppler spectrum matrix is ​​obtained for each sub-interval. These matrices represent the signal information in different Doppler frequency ranges. Modulo operation is performed on the range Doppler spectrum matrix in each sub-interval. The modulo operation can extract the amplitude information of the complex number, that is, the energy distribution of the signal. The modulo matrix is ​​added together. The purpose of this is to combine the signal energy in different sub-intervals to obtain a smoother background noise detection matrix. In this way, the impact of noise can be reduced, making the target signal easier to detect.

[0119] Exemplarily, in the above step 130, obtaining the range index and Doppler index of the target according to the range-Doppler spectrum matrix includes:

[0120] Step 131 , performing target detection on the detection matrix of the first waveform using a constant false alarm detection algorithm.

[0121] Specifically, constant false alarm detection (CFAR) algorithm is a method for detecting interference targets in radar signal processing. Here, it is used to process and analyze the detection matrix of the first waveform to complete target detection. The CFAR algorithm can dynamically adjust the detection threshold to adapt to different background noise levels according to the statistical properties of the ambient background noise. The purpose of doing so is to reduce false alarms as much as possible under various background conditions, that is, to effectively detect targets while keeping a constant false alarm probability.

[0122] Step 132: Use a preset decoding method and combine the range Doppler spectrum matrix of the second waveform to perform transmit antenna separation to achieve DDMA decoding.

[0123] For example, the Empty-band method is used in combination with the RD matrix of the second waveform to complete the transmission antenna separation (i.e., DDMA decoding). The Empty-band method is a technology for transmitting antenna separation, which is used in radar systems that use diversity beamforming technology. In diversity beamforming technology, in order to distinguish the echo signals generated by different transmitting antennas, an empty band (Empty-band) is usually reserved in the transmitting beamforming, that is, there is no signal or the signal is very weak in a certain frequency band. This can be used as a reference signal for subsequent signal processing. After the previous processing, the second waveform has obtained the corresponding RD matrix, which contains signal information on distance and Doppler frequency.

[0124] Step 133, based on the information obtained by separating the transmitting antennas, determine the range index and Doppler index of the target.

[0125] Among them, the distance index is the time delay of the target echo signal measured by the radar system, which can determine the distance between the target and the radar system. This distance information can be expressed as a distance index, which is usually expressed in distance units (such as meters or kilometers) in the radar system. The Doppler effect refers to the change in the frequency of the echo signal when the target moves relative to the radar system. By analyzing the frequency change of the echo signal, the speed information of the target, that is, the Doppler index, can be determined. The Doppler index is usually expressed in speed units (such as meters per second) in the radar system. By determining these two types of index information, the radar system can accurately understand the position and speed of the target, thereby achieving tracking and identification of the target.

[0126] For example, the distance index and Doppler index (Tx 1) of the target are obtained, where the Doppler index is recorded as DopIdx, and the Doppler index (Tx 1) is expanded to obtain Tx 1~N Tx The Doppler index of

[0127] DopIdx+[0 N d / f(N Tx )…(N d -1) / f(N Tx )].

[0128] When the Doppler index is expanded, it may exceed a certain range. To solve this problem, the out-of-range index needs to be processed, that is, folded. Specifically, the out-of-range index is subtracted from the length of the corresponding range to keep it within a reasonable range, that is, DopIdx+[0 N d / f(N Tx )…(N d -1) / f(N Tx )] is greater than N d The elements of need to be subtracted from Nd .

[0129] That is, in the index vector after the Doppler index is expanded, if an element exceeds N d , we need to subtract N from it d , to ensure that the index is within a reasonable range.

[0130] Exemplarily, in the above step 140, obtaining the amplitudes of the first waveform and the second waveform according to the distance index and the Doppler index includes:

[0131] Step 141 , according to the acquired range index and Doppler index of the target, locate the target on the range-Doppler spectrum matrix of the first waveform, and obtain its amplitude.

[0132] Step 142: locate the target on the range-Doppler spectrum matrix of the second waveform according to the acquired range index and Doppler index of the target, and obtain its amplitude.

[0133] When the radar system sends a signal and receives an echo, the target object will reflect some of the energy. This reflected signal can be displayed on the range-Doppler spectrum matrix after processing. In these spectrum matrices, the amplitude is a parameter used to represent the strength of the signal reflected from the target, usually expressed in digital form. By detecting the amplitude at different positions, the intensity distribution of the target at different distances and speeds can be understood.

[0134] For example, in the above steps 141 to 142, the target distance index obtained above and Tx 1 to N are used. Tx The Doppler index of the first waveform and the second waveform is extracted on the RD matrix. Each RD matrix can extract N Tx Amplitudes, corresponding to Tx 1~N Tx , denoted as A1(n), n=[1,…,N Tx ] and A2(n), n=[1,…,N Tx ].

[0135] Exemplarily, in the above step 150, judging whether the target is a real target or an interference target according to the amplitudes of the first waveform and the second waveform includes:

[0136] Step 151, comparing the amplitude difference corresponding to the first waveform and the second waveform.

[0137] Step 152: if the amplitude difference satisfies the set threshold condition, the target is determined to be a real target; otherwise, the target is determined to be an interference target caused by parallel interference.

[0138] For example, the threshold condition is set as:

[0139] And i≠j

[0140]

[0141] Wherein, A1(i) represents the amplitude corresponding to the i-th transmitting antenna transmitting the first waveform, A1(j) represents the amplitude corresponding to the j-th transmitting antenna transmitting the first waveform, i and j are positive integers. A2(i) represents the amplitude corresponding to the i-th transmitting antenna transmitting the second waveform, and A2(j) represents the amplitude corresponding to the j-th transmitting antenna transmitting the second waveform. Represents any i, j. Thr A represents the set amplitude difference threshold, and K represents the set of transmitting antennas whose code is 0.

[0142] When the absolute value of the amplitude difference corresponding to any two different transmitting antennas in A1 is less than the threshold, and the absolute value of the amplitude difference corresponding to any two different transmitting antennas in A2 except the transmitting antenna corresponding to the set area K is less than the threshold, and the absolute value of the amplitude difference corresponding to any transmitting antenna not belonging to the set K and any transmitting antenna belonging to the set area K is greater than or equal to the threshold, it means that the amplitude difference meets the threshold condition set above, and the target is determined to be a real target. Otherwise, the target is determined to be an interference target caused by parallel interference.

[0143] The following describes the interference target detection method provided by the present application through an embodiment.

[0144] For example, suppose there are two radars, both operating in the same frequency band (such as 77GHz), with the same waveform parameters (sweep period, modulation frequency, etc.). The number of transmitting antennas is the same (such as N Tx =4), f(N Tx )=4, the number of chirps is 512, N d =256, and the second waveform turns off the last transmitting antenna, that is, its transmitting antenna code is

[1110] . A Set to 6dB. The following analyzes the algorithm performance of the jamming radar working in TDMA (time division multiple access) and DDMA (dynamic multiple access) modes. The first waveform can be called waveform one, and the second waveform can be called waveform two.

[0145] Embodiment 1: The jamming radar works in TDMA mode, that is, only one transmitting antenna works for each chirp.

[0146] That is to say, the jamming radar uses the time division multiple access (TDMA) mode to work. In TDMA mode, only one transmitting antenna is working for each chirp (pulse group). This means that in each chirp cycle, only one transmitting antenna is used to send signals, while the other transmitting antennas are idle or performing other tasks. TDMA mode is a multiple access communication technology that divides time into different time slots. In each time slot, only one user or device can send data or signals, and other users or devices need to wait for their time slots. In radar applications, TDMA mode can avoid multiple transmitting antennas sending signals at the same time.

[0147] Please refer to Figure 2a , Figure 2b , Figure 3a , Figure 3b , Figure 4a , Figure 4b , Figure 2a is the RD diagram of waveform 1 in TDMA mode of embodiment 1 of the present application, Figure 2b This is the RD diagram of waveform 2 in TDMA mode in the first embodiment of the present application. Figure 3a is an index diagram of a waveform target 1 in a TDMA mode of an embodiment of the present application, Figure 3b is an index diagram of waveform 2 target 1 in TDMA mode of embodiment 1 of the present application, Figure 4a is an index diagram of a waveform target 2 in a TDMA mode of an embodiment of the present application, Figure 4b It is an index diagram of waveform 2 target 2 in TDMA mode in embodiment 1 of the present application.

[0148] After CFAR detection and DDMA demodulation based on the Empty-band method, the Doppler indexes corresponding to target 1 are 25, 89, 153, and 217 (corresponding to Tx 1 to N Tx ), the Doppler indexes corresponding to target 2 should be 49, 113, 177 and 241 respectively (corresponding to Tx 1~N Tx ).

[0149] Target 1: A1 = [32, 32, 32, 32], A2 = [32, 32, 32, -10].

[0150] Target 2: A1 = [33, -18, -17, -9], A2 = [33, -15, -10, -23].

[0151] Obviously, the above conditions are met for target 1, but not for target 2. Therefore, target 1 is the real target, while target 2 is the false target caused by the jamming radar.

[0152] Embodiment 2: The jamming radar operates in DDMA mode (DDMA phase shift coding is consistent).

[0153] That is, the jammer radars are operating in dynamic distributed multiple access (DDMA) mode, and the phase shift coding of all jammer radars is consistent. DDMA is a distributed multiple access technology. In DDMA mode, different radars use different transmit phase shift coding so that they can distinguish each other and avoid collision. But in case 2, the jammer radars are operating in DDMA mode, and the phase shift coding of all jammer radars is consistent, which means that they all use the same transmit phase shift coding to communicate.

[0154] Please refer to Figure 5a , Figure 5b , Figure 6a , Figure 6b , Figure 7a , Figure 7b , Figure 5a This is the RD diagram of waveform 1 in DDMA mode of the second embodiment of the present application. Figure 5b This is the RD diagram of waveform 2 in DDMA mode of embodiment 2 of the present application. Figure 6a is an index diagram of waveform 1 target 1 in DDMA mode of the second embodiment of the present application, Figure 6b is an index diagram of waveform 2 target 1 in DDMA mode of embodiment 2 of the present application, Figure 7a is an index diagram of waveform 1 target 2 in DDMA mode of the second embodiment of the present application, Figure 7b It is an index diagram of waveform 2 target 2 in DDMA mode of embodiment 2 of the present application.

[0155] After CFAR detection and DDMA demodulation based on the Empty-band method, the Doppler indexes corresponding to target 1 are 25, 89, 153, and 217 (corresponding to Tx 1 to N Tx ), the Doppler indexes corresponding to target 2 should be 49, 113, 177 and 241 respectively (corresponding to Tx 1~N Tx ).

[0156] Target 1: A1 = [32, 32, 32, 32], A2 = [32, 32, 32, -10].

[0157] Target 2: A1 = [33, 33, 33, 33], A2 = [33, 33, 33, 33].

[0158] Obviously, the above conditions are met for target 1, but not for target 2. Therefore, target 1 is the real target, while target 2 is the false target caused by the jamming radar.

[0159] Embodiment 3: The jamming radar operates in DDMA mode (DDMA phase shift coding is inconsistent).

[0160] That is to say, the jamming radar uses the dynamic distributed multiple access (DDMA) mode to work, and the transmission phase shift coding of all jamming radars is different. In the dynamic distributed multiple access (DDMA) mode, different radars can use different transmission phase shift coding to distinguish each other and prevent collision and mutual interference. Case three assumes that the phase shift coding used by each jamming radar is different, that is, there is no coordination or unified coding method between them.

[0161] Please refer to Figure 8a , Figure 8b , Figure 9a , Figure 9b , Fig.10a , Fig.10b , Fig.11a , Fig.11b . Figure 8a This is the RD diagram of waveform 1 in DDMA mode of embodiment 3 of the present application. Figure 8b This is the RD diagram of waveform 2 in DDMA mode of embodiment 3 of the present application. Figure 9a is an index diagram of waveform 1 target 1 in DDMA mode of embodiment 3 of the present application, Figure 9b is an index diagram of waveform 2 target 1 in DDMA mode of embodiment 3 of the present application, Fig.10a is an index diagram of waveform 1 target 2 in DDMA mode of embodiment 3 of the present application, Fig.10b is an index diagram of waveform 2 target 2 in DDMA mode of embodiment 3 of the present application, Fig.11a is an index diagram of waveform 1 target 3 in DDMA mode of embodiment 3 of the present application, Fig.11b It is an index diagram of waveform 2 target 3 in DDMA mode of embodiment 3 of the present application.

[0162] After CFAR detection and DDMA demodulation based on the Empty-band method, the Doppler indexes corresponding to target 1 are 25, 89, 153, and 217 (corresponding to Tx 1 to N Tx ), in this case, target 2 will detect two targets, marked as target 2 and target 3. The corresponding Doppler indexes should be 49, 113, 177 and 241 respectively (corresponding to Tx 1~N Tx ) and 81, 145, 209 and 17 (corresponding to Tx 1~N Tx ).

[0163] Target 1: A1 = [32, 32, 32, 32], A2 = [32, 32, 32, -10].

[0164] Target 2: A1 = [33, 33, -18, -9], A2 = [33, 33, -11, -23].

[0165] Target 3: A1 = [33, 33, -13, -11], A2 = [33, 33, -13, -11].

[0166] Obviously, the above conditions are met for target 1, but not for targets 2 and 3. In this case, target 1 is the real target, while targets 2 and 3 are false targets caused by the jamming radar.

[0167] In summary, the interference target detection method described in the present application, its basic idea is that when processing the interfered radar (i.e., this radar) signal, by configuring two waveforms (i.e., the first waveform and the second waveform) and transmitting alternately, and then performing fast-time and slow-time discrete Fourier transforms on the intermediate frequency signals of the two waveforms, two range Doppler spectrum matrices (RD matrices) are obtained. Due to the characteristics of the dynamic distributed multiple access (DDMA) waveform, and the design of two waveforms with different numbers of transmitting antennas, the number of effective peaks of the same target in the Doppler dimension will correspond to the number of transmitting antennas. The false targets caused by the interference radar lack this dynamic change characteristic of the transmitting antenna, or its dynamic change characteristic is inconsistent with this radar.

[0168] Therefore, the number of effective peaks of the false targets caused by the jamming radar on the two RD matrices of this radar is inconsistent with that of the real targets. By comparing the difference in the number of effective peaks on the two RD matrices, the false targets caused by parallel jamming can be detected. This method uses the design of waveform parameters to effectively distinguish the real targets from the jamming targets, thereby realizing the detection and elimination of false targets.

[0169] The interference target detection device provided in the present application is described below. The interference target detection device described below and the interference target detection method described above can be referenced to each other.

[0170] Please refer to Fig.12 , Fig.12 The structure diagram of the interference target detection device provided by the present application is as follows. An interference target detection device 1200 is used to detect interference targets generated by an interference radar to the radar, and includes a waveform configuration module 1201, a Doppler spectrum acquisition module 1202, a target index acquisition module 1203, an amplitude acquisition module 1204, and a target judgment module 1205.

[0171] Exemplarily, the waveform configuration module 1201 is used to configure the first waveform and the second waveform to be transmitted by the radar.

[0172] Exemplarily, the Doppler spectrum acquisition module 1202 is used to acquire the range Doppler spectrum matrix of the first waveform and the second waveform.

[0173] Exemplarily, the target index acquisition module 1203 is used to acquire the range index and Doppler index of the target according to the range-Doppler spectrum matrix.

[0174] Exemplarily, the amplitude acquisition module 1204 is used to acquire the amplitudes of the first waveform and the second waveform according to the distance index and the Doppler index.

[0175] Exemplarily, the target judgment module 1205 is used to judge whether the target is a real target or an interference target according to the amplitudes of the first waveform and the second waveform.

[0176] Exemplarily, the waveform configuration module 1201 is also used for:

[0177] Transmit a certain number of chirps for each frame signal, and divide the certain number of chirps into two groups with odd and even indexes, corresponding to the first waveform and the second waveform respectively, so that each group of waveforms has its own number of chirps;

[0178] Phase shifters are used to shift the preset frequency of each transmitting antenna to achieve DDMA encoding of the waveform.

[0179] Exemplarily, the Doppler spectrum acquisition module 1202 is further used for:

[0180] Performing a discrete Fourier transform of the intermediate frequency signals of the first waveform and the second waveform in fast time dimension and slow time dimension to obtain two sets of range Doppler spectrum matrices;

[0181] Processing the range Doppler spectrum matrix to equally divide it into a number of sub-intervals in the Doppler dimension;

[0182] A modulo operation is performed on the range-Doppler spectrum matrix in each subinterval and the matrix is ​​added together to obtain a detection matrix.

[0183] Exemplarily, the target index acquisition module 1203 is further used for:

[0184] Performing target detection on the detection matrix of the first waveform using a constant false alarm detection algorithm;

[0185] Using a preset decoding method and combining the range Doppler spectrum matrix of the second waveform to perform transmit antenna separation to achieve DDMA decoding;

[0186] Based on the information obtained by separating the transmitting antennas, a range index and a Doppler index of the target are determined.

[0187] Exemplarily, the amplitude acquisition module 1204 is further used for:

[0188] According to the acquired range index and Doppler index of the target, locate the target on the range-Doppler spectrum matrix of the first waveform, and obtain its amplitude;

[0189] According to the acquired range index and Doppler index of the target, the target is located on the range-Doppler spectrum matrix of the second waveform, and its amplitude is acquired.

[0190] Exemplarily, the target determination module 1205 is further used for:

[0191] comparing the amplitude difference corresponding to the first waveform and the second waveform;

[0192] If the amplitude difference meets the set threshold condition, the target is determined to be a real target;

[0193] Otherwise, the target is determined to be an interference target caused by parallel interference.

[0194] Exemplarily, the waveform configuration module 1201 is also used for:

[0195] For the second waveform, one or more transmitting antennas are turned off, and for the first waveform, all transmitting antennas are kept turned on;

[0196] Determine a code length according to the number of transmit antennas, and assign a code bit to each transmit antenna for each of the first waveform and the second waveform;

[0197] A coding feature is matched with each transmitting antenna to form a set of transmitting antenna coding sequences of a first waveform and a second waveform, wherein the coding feature uses binary to represent whether the transmitting antenna is in an on state and whether the transmitting antenna is in an off state.

[0198] In some embodiments of the present application, the present application also provides a radar device, including a memory, a processor, and a computer program stored on the memory and running on the processor, and when the processor executes the program, the steps of the interference target detection method as described in any one of the above items are implemented.

[0199] When the processor executes this program, it will follow the steps of the interference target detection method described above. Specifically, the processor will perform fast-time and slow-time discrete Fourier transforms on the signal received by the radar to obtain two range Doppler spectrum matrices (RD matrices), and then compare the difference in the number of effective peaks on the two matrices, thereby realizing the detection of false targets caused by parallel interference.

[0200] Therefore, the radar device realizes an effective false interference target detection method through the coordinated work of the memory, the processor and the computer program, thereby improving the detection accuracy and anti-interference capability of the radar system for real targets.

[0201] On the other hand, the present application also provides a computer program product, which includes a computer program stored on a non-transitory computer-readable storage medium, and the computer program includes program instructions. When the program instructions are executed by a computer, the computer can execute the interference target detection method provided by the above-mentioned methods.

[0202] On the other hand, the present application also provides a non-transitory computer-readable storage medium having a computer program stored thereon, and when the computer program is executed by a processor, the interference target detection method provided above is implemented.

[0203] The embodiments of the present application provide a radar device, a computer program product, and a processor-readable storage medium, on which the computer program stored enables the processor to implement all the method steps implemented by the above-mentioned method embodiment and can achieve the same technical effect. The parts and beneficial effects of this embodiment that are the same as those of the method embodiment will not be described in detail here.

[0204] The device embodiments described above are merely illustrative, wherein the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the scheme of this embodiment. Ordinary technicians in this field can understand and implement it without paying creative labor.

[0205] Through the description of the above implementation methods, those skilled in the art can clearly understand that each implementation method can be implemented by means of software plus a necessary general hardware platform, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solution is essentially or the part that contributes to the prior art can be embodied in the form of a software product, and the computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, a disk, an optical disk, etc., including a number of instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in each embodiment or some parts of the embodiments.

[0206] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A method for detecting an interference target, characterized in that: Used to detect interference targets generated by interference radars to the radar, the interference target detection method includes: Configuring a first waveform and a second waveform to be transmitted by the radar; Acquire the range Doppler spectrum matrix of the first waveform and the second waveform; According to the range-Doppler spectrum matrix, obtaining a range index and a Doppler index of the target; Acquire the amplitudes of the first waveform and the second waveform according to the distance index and the Doppler index; According to the amplitudes of the first waveform and the second waveform, it is determined whether the target is a real target or an interference target.

2. The interference target detection method according to claim 1, characterized in that: The configuration of the first waveform and the second waveform to be transmitted by the radar includes: Transmitting a certain number of chirps for each frame signal, and dividing the certain number of chirps into two groups with odd and even indexes, corresponding to the first waveform and the second waveform respectively, so that each group of waveforms has its own number of chirps; A phase shifter is used to shift each transmitting antenna by a preset frequency to achieve DDMA coding of the waveform.

3. The interference target detection method according to claim 1, characterized in that: The acquiring of the range Doppler spectrum matrix of the first waveform and the second waveform comprises: Performing a discrete Fourier transform of the intermediate frequency signals of the first waveform and the second waveform in fast time dimension and slow time dimension to obtain two sets of range Doppler spectrum matrices; Processing the range-Doppler spectrum matrix to equally divide it into a number of sub-intervals in the Doppler dimension; A modulo operation is performed on the range Doppler spectrum matrix in each subinterval and the matrix is ​​added together to obtain a detection matrix.

4. The interference target detection method according to claim 3, characterized in that: The acquiring the range index and Doppler index of the target according to the range-Doppler spectrum matrix comprises: Performing target detection on the detection matrix of the first waveform using a constant false alarm detection algorithm; Using a preset decoding method and combining the range Doppler spectrum matrix of the second waveform to perform transmit antenna separation to achieve DDMA decoding; Based on the information obtained by separating the transmitting antennas, a range index and a Doppler index of the target are determined.

5. The interference target detection method according to claim 1, characterized in that: The acquiring the amplitudes of the first waveform and the second waveform according to the distance index and the Doppler index comprises: According to the acquired range index and Doppler index of the target, locate the target on the range-Doppler spectrum matrix of the first waveform, and obtain its amplitude; According to the acquired range index and Doppler index of the target, the target is located on the range-Doppler spectrum matrix of the second waveform, and its amplitude is acquired.

6. The interference target detection method according to claim 1, characterized in that: The determining, according to the amplitudes of the first waveform and the second waveform, whether the target is a real target or an interference target comprises: comparing the amplitude difference corresponding to the first waveform and the second waveform; If the amplitude difference meets the set threshold condition, the target is determined to be a real target; Otherwise, the target is determined to be an interference target caused by parallel interference.

7. The interference target detection method according to claim 2, characterized in that: The configuration of the first waveform and the second waveform to be transmitted by the radar further includes: For the second waveform, one or more transmitting antennas are turned off, and for the first waveform, all transmitting antennas are kept turned on; Determine a code length according to the number of transmit antennas, and assign a code bit to each transmit antenna for each of the first waveform and the second waveform; A coding feature is matched with each transmitting antenna to form a set of transmitting antenna coding sequences of a first waveform and a second waveform, wherein the coding feature uses binary to represent whether the transmitting antenna is in an on state and whether the transmitting antenna is in an off state.

8. An interference target detection device, characterized in that: Used to detect interference targets generated by interference radar to the radar, the interference target detection device includes: A waveform configuration module, used to configure the first waveform and the second waveform to be transmitted by the radar; A Doppler spectrum acquisition module, used to acquire the range Doppler spectrum matrix of the first waveform and the second waveform; A target index acquisition module, used to acquire the range index and Doppler index of the target according to the range-Doppler spectrum matrix; an amplitude acquisition module, configured to acquire the amplitudes of the first waveform and the second waveform according to the distance index and the Doppler index; The target judgment module is used to judge whether the target is a real target or an interference target according to the amplitudes of the first waveform and the second waveform.

9. A radar device, comprising a memory, a processor, and a computer program stored in the memory and running on the processor, characterized in that: When the processor executes the program, the steps of the interference target detection method according to any one of claims 1 to 7 are implemented.

10. A non-transitory computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the interference target detection method according to any one of claims 1 to 7 are implemented.

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