Method and apparatus for low speed non-radial motion target detection using radar

Abstract

The application discloses a method and device for detecting low-speed non-radial motion targets by using radar, and relates to the technical field of radar signal processing, and solves the problem that the Doppler characteristics of targets and background clutter are similar in radar data in the prior art. The method comprises the following steps: performing pulse compression on a received signal received by a radar, performing Fourier transform, and selecting a plurality of one-dimensional Doppler data on a distance unit where a target is located in an azimuth direction; searching each Doppler center signal, performing signal frequency domain decomposition, and obtaining high-frequency components and low-frequency components corresponding to each Doppler center signal; performing frequency shifting processing on the components respectively, estimating the Doppler frequency modulation of the received signal by using the components after frequency shifting, and obtaining the Doppler frequency modulation of the target. The method realizes the detection of weak targets according to the focusing characteristics of radar data reflected by the target in non-radial motion in Doppler-pseudospectrum.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of radar signal processing, and in particular to a method and device for detecting low-speed non-radial motion targets using radar. BACKGROUND

[0002] Radar has the advantages of all-weather and all-day, and can complete the detection and tracking task of moving targets. The core idea of using radar to monitor moving targets is to find an image domain so that the characteristics of the target and the characteristics of the clutter in the scene are obviously distinguished. The main difference between moving targets and background clutter is reflected in the range-doppler spectrum. Usually, the constant false alarm rate (CFAR) algorithm is used in the range-doppler domain to complete target detection. In recent years, with the development of deep learning, deep learning methods have also been applied to target detection. When a low-speed moving target moves non-radially relative to the radar (radial motion means that the moving target moves linearly towards the radar receiving antenna), the radial projection of the target speed (i.e. the speed of the target relative to the radar) will further decrease. At this time, the Doppler characteristics of the target and the background clutter in the radar data are similar. Therefore, there is a certain coupling between the target data and the background clutter in the range-doppler domain, and it is difficult to complete the detection task of low-speed moving targets in the traditional range-doppler domain.

[0003] Therefore, how to distinguish the Doppler characteristics of the target and the background clutter in the radar data is a problem that needs to be solved at present. SUMMARY

[0004] The present application provides a method and device for detecting low-speed non-radial motion targets using radar, which solves the problem that the Doppler characteristics of the target and the background clutter in the radar data are similar in the prior art, and realizes the detection of weak targets according to the focusing characteristics of the Doppler-pseudo spectrum of the radar data reflected by the non-radial motion of the target.

[0005] In a first aspect, the present application provides a method for detecting low-speed non-radial motion targets using radar, which comprises:

[0006] Pulse compression is performed on the received signal received by the radar to obtain a pulse compression signal;

[0007] The pulse compression signal is subjected to Fourier transform along the direction bit to obtain azimuth two-dimensional data;

[0008] A plurality of one-dimensional Doppler data is extracted from the distance unit where the target is located in the azimuth direction to obtain a processed data set;

[0009] A Doppler center signal set is obtained by searching for the Doppler center signal of each processed data in the processed data set;

[0010] performing signal frequency domain decomposition on each Doppler center signal in the set of Doppler center signals to obtain a high frequency component and a low frequency component corresponding to each Doppler center signal;

[0011] performing frequency shifting on the high frequency component and the low frequency component corresponding to each Doppler center signal respectively to obtain a frequency shifted high frequency component and a frequency shifted low frequency component corresponding to each Doppler center signal;

[0012] estimating the Doppler frequency modulation of the received signal by using the frequency shifted high frequency component and the frequency shifted low frequency component to obtain the Doppler frequency modulation of the target.

[0013] With reference to the first aspect, in a possible implementation manner, the pulse compression signal is denoted as:

[0014]

[0015] wherein B is a bandwidth of the transmitted signal; is a sampling time sequence of a radar receiver; t m is a time sequence of a radar transmitter transmitting a pulse; is a delay time of a radar transmitted signal reflected by a target and received by the receiver; is a relative distance of the target to the radar; R0, X n is an initial position coordinate of the target, v is a target motion speed; c is a light speed; exp(·) represents an exponential function with a natural constant e as a base; j represents an imaginary unit; λ is a center wavelength of the radar transmitted signal; π is a circular constant.

[0016] With reference to the first aspect, in a possible implementation manner, the azimuth two-dimensional data is denoted as:

[0017]

[0018] wherein, γ a represents the Doppler frequency modulation of the target f a is a Doppler frequency point.

[0019] With reference to the first aspect, in a possible implementation manner, the performing signal frequency domain decomposition on each Doppler center signal to obtain a high frequency component and a low frequency component corresponding to each Doppler center signal comprises:

[0020] filtering each Doppler center signal by using a high-pass filter and a low-pass filter to obtain a high frequency component and a low frequency component corresponding to each Doppler center signal.

[0021] With reference to the first aspect, in a possible implementation manner, the estimating the Doppler frequency modulation of the target from the received signal by using the frequency-shifted high-frequency component and the frequency-shifted low-frequency component comprises:

[0022] calculating a first conjugate component of the frequency-shifted low-frequency component, and multiplying the first conjugate component with the frequency-shifted high-frequency component to obtain a first result;

[0023] performing Fourier transform on the first result to obtain transform data;

[0024] determining a column with a maximum value in the transform data as the Doppler frequency of the target, and determining the movement speed of the target by using the Doppler frequency of the target;

[0025] determining that the target exists and completing detection according to the movement speed.

[0026] With reference to the first aspect, in a possible implementation manner, the processed data is represented as:

[0027]

[0028] wherein γ a represents the Doppler frequency modulation of the target; f a represents a Doppler frequency point; and A represents a constant,

[0029] With reference to the first aspect, in a possible implementation manner, the Doppler center signal is represented as:

[0030]

[0031] wherein f dc represents a Doppler value of the traversal search; f a represents a Doppler frequency point; and A represents a constant, γ a represents the Doppler frequency modulation of the target.

[0032] The second aspect of the present application provides a device for detecting a low-speed non-radial motion target by using a radar, which comprises:

[0033] a signal compression module, configured to perform pulse compression on a received signal received by the radar to obtain a pulse compression signal;

[0034] a signal transform module, configured to perform Fourier transform on the pulse compression signal along a direction bit to obtain direction bit azimuth two-dimensional data;

[0035] The signal processing module is configured to extract one-dimensional Doppler data on a distance unit where the target is located in the direction bit azimuth direction, and obtain processed data.

[0036] The signal searching module is configured to search for Doppler center signals in the processed data, and obtain a plurality of Doppler center signals.

[0037] The signal decomposition module is configured to perform signal frequency domain decomposition on each Doppler center signal, and obtain high-frequency components and low-frequency components corresponding to each Doppler center signal.

[0038] The signal frequency shifting module is configured to perform frequency shifting processing on the high-frequency components and the low-frequency components corresponding to each Doppler center signal respectively, and obtain frequency-shifted high-frequency components and frequency-shifted low-frequency components corresponding to each Doppler center signal.

[0039] The estimation module is configured to estimate the Doppler frequency modulation of the received signal by using the frequency-shifted high-frequency components and the frequency-shifted low-frequency components, and obtain the Doppler frequency modulation of the target.

[0040] In a third aspect, the present application provides a server for completing low-speed non-radial motion target detection using a radar, the server comprising a memory and a processor;

[0041] The memory is configured to store computer executable instructions;

[0042] The processor is configured to execute the computer executable instructions to implement the method for completing low-speed non-radial motion target detection using a radar.

[0043] In a fourth aspect, the present application provides a computer readable storage medium having executable instructions, and a computer executing the executable instructions can implement the method for completing low-speed non-radial motion target detection using a radar.

[0044] The one or more technical solutions provided in the present application have at least the following technical effects or advantages:

[0045] (1) The present application proposes a Doppler frequency modulation in the process of detecting a non-radial motion target, and in the Doppler image corresponding to the Doppler frequency modulation, the target and the background clutter have new different characteristics, and the slow target detection can be completed according to the new characteristic difference.

[0046] (2) The present application first performs pulse compression and azimuth Fourier transform on the non-radial motion target, preliminarily completes target energy accumulation, and then converts to the Doppler frequency modulation, and the target detection performance for small targets and clutter edges (target and background clutter coupling in the characteristic domain) is good. BRIEF DESCRIPTION OF DRAWINGS

[0047] Figure 1 A method step flow chart for using radar to complete low-speed non-radial motion target detection is provided for the embodiments of the present application.

[0048] Figure 2 A target non-radial motion model schematic diagram is provided for the embodiments of the present application.

[0049] Figure 3 An azimuth two-dimensional data range-Doppler map is provided for the embodiments of the present application.

[0050] Figure 4 A target corresponding distance unit range-Doppler profile map is provided for the embodiments of the present application.

[0051] Figure 5 A pseudo-spectrum generated by the target corresponding distance unit range-Doppler profile map is provided for the embodiments of the present application. DETAILED DESCRIPTION

[0052] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the present application.

[0053] In a first aspect, the present application provides a method for using radar to complete low-speed non-radial motion target detection, which comprises the following steps S101-S107. Referring to Figure 1 A method step flow chart for using radar to complete low-speed non-radial motion target detection is provided for the embodiments of the present application.

[0054] S101, pulse compression is performed on the received signal received by the radar to obtain a pulse compression signal. After the radar transmits a linear frequency modulation signal, the radar receiver receives the linear frequency modulation signal reflected back by the target.

[0055] Specifically, in step S101, the pulse compression signal is denoted as:

[0056]

[0057] Wherein, B is the bandwidth of the transmitted signal; is a radar receiver sampling time sequence; t m is a radar transmitter pulse transmission time sequence; is a delay time of the radar transmitted signal reflected by the target and received by the receiver; is the relative distance between the target and the radar; R0, X nis the initial position coordinate of the target, v is the target motion velocity; c is the light speed; exp(·) represents the exponential function with the natural constant e as the base; j represents the imaginary unit; λ is the center wavelength of the radar transmitted signal; and π is the circular constant.

[0058] For example, refer to Figure 2 is a schematic diagram of a non-radial motion model of a target.

[0059] In step S101, pulse compression is performed on the received signal of the radar, and the implementation includes radar receiver hardware and signal processing methods.

[0060] In step S102, the pulse compression signal is subjected to Fourier transform along the direction bit to obtain the azimuth two-dimensional data.

[0061] Specifically, in step S102, the azimuth two-dimensional data is represented as:

[0062]

[0063] wherein, γ a represents the Doppler frequency modulation of the target f a is the Doppler frequency point.

[0064] In step S102, Fourier transform is performed on the pulse compression signal after pulse compression of the radar, and the specific implementation includes Fourier transform (FFT) and discrete Fourier transform (DFT), or the purpose can also be achieved through inverse Fourier transform (IFFT) and discrete inverse Fourier transform (IDFT).

[0065] In step S103, a plurality of one-dimensional Doppler data is taken out on the distance unit where the target is located in the azimuth direction to obtain the processed data set S(f a ). For example, Figure 3 is a range-Doppler plot of the azimuth two-dimensional data.

[0066] Specifically, in step S103, the one-dimensional Doppler data is taken out by selecting the distance unit where the target is located, and only the term in the data that varies with the Doppler frequency point is left to obtain the processed data set. The processed data is represented as:

[0067]

[0068] wherein, γ a represents the Doppler frequency modulation of the target; f a represents the Doppler frequency point; and A represents a constant,

[0069] For example, in this step, the distance unit is selected, and the specific implementation steps are as follows:

[0070] (1) Calculate the range cell of radar data. Each cell in the raw one-dimensional range image data of the radar corresponds to the actual distance in the physical space. The distance interval corresponding to adjacent range cells is consistent with the radar range resolution (some embodiments choose to use distance super-resolution algorithms such as data extrapolation, frequency domain zero padding, etc. In these scenarios, the distance interval corresponding to adjacent range cells is affected by the radar range resolution and the resolution enhancement multiple), which is determined by the bandwidth B of the radar transmission pulse.

[0071] (2) Calculate the range cell of the target in advance and select the appropriate range cell. For example, in this embodiment, the target is in the area flying close to the radar at a distance of 400-450 meters. The range cell in this area can be selected for subsequent steps.

[0072] S104, search for the Doppler center signal set for each processed data in the processed data set.

[0073] The Doppler center signal is represented as:

[0074]

[0075] where f dc represents the Doppler value of the traversal search; f a represents the Doppler frequency point; A represents a constant, γ a represents the Doppler frequency of the target.

[0076] Sliding traversal search Doppler center. Since the target is a non-cooperative target, the target's range Doppler center cannot be obtained in advance. In this embodiment, the simplest traversal search method is selected, which searches for each Doppler value in the Doppler interval. The search step is determined by the corresponding step of the input Doppler spectrum of the original radar data (in some embodiments, an integer multiple of the corresponding step of the input Doppler spectrum can be selected as the search step). In this embodiment, the input Doppler spectrum is -100Hz-100Hz, and the step is 8Hz. In some embodiments, the general Doppler center position of the target is known in advance, and this part of the Doppler center can be selected for traversal search.

[0077] S105, signal frequency domain decomposition is performed on each Doppler center signal in the Doppler center signal set to obtain the high-frequency component and the low-frequency component corresponding to each Doppler center signal.

[0078] Specifically, in step S105, signal frequency domain decomposition is performed on each Doppler center signal to obtain high frequency components and low frequency components corresponding to each Doppler center signal, including: filtering each Doppler center signal by using a high-pass filter and a low-pass filter to obtain high frequency components and low frequency components corresponding to each Doppler center signal. For example, a low-pass filter and a high-pass filter are selected. The low-pass filter can be selected to filter the signal to obtain the low frequency component, and the high-pass filter can be selected to filter the signal to obtain the high frequency component. As much as possible, high-order low-pass filters and high-order high-pass filters are selected to ensure the filtering effect. In this embodiment, the demarcation line of the high frequency component and the low frequency component is zero frequency, and the frequency passing range of the low-pass filter and the high-pass filter needs to be set correspondingly, for example, the low-pass filter can pass below zero frequency and filter out above zero frequency, and the high-pass filter is opposite to the low-pass filter.

[0079] Specifically, another implementation in step S105 is data addressing. The data received by the radar and subsequently processed is discrete data, which is arranged neatly in a matrix. The data address corresponding to the high frequency data can be directly selected in the frequency domain data to obtain the high frequency component, and the data address corresponding to the low frequency data can be directly selected in the frequency domain data to obtain the low frequency component. In this embodiment, the demarcation line of the high frequency component and the low frequency component is zero frequency, which corresponds to the center position of the data address, and the frequency division effect can be achieved by separating from the center.

[0080] Specifically, in step S105, the signal frequency of each Doppler center is decomposed into high frequency components S U and low frequency components S L , which can be represented as:

[0081]

[0082]

[0083] S106, respectively, the high frequency components and low frequency components corresponding to each Doppler center signal are frequency shifting processed to obtain the frequency shifted high frequency components and frequency shifted low frequency components corresponding to each Doppler center signal.

[0084] For example, the high frequency component S U is left frequency shifted by Δf, and the low frequency component S L is right frequency shifted by Δf, which can be represented as:

[0085]

[0086]

[0087] This step requires shifting the frequency of high-frequency components to the left and low-frequency components to the right. The shifting method is similar, and a detailed description will be given using the high-frequency component as an example. First, the filtered high-frequency component is converted to the time domain; second, the time domain is multiplied by a phase factor; finally, it is converted back to the frequency domain to complete the frequency shifting process. Those skilled in the art will clearly understand the frequency shifting method.

[0088] The selection of the frequency shift amount Δf is also protected by this invention. The motion of the target relative to the radar generates a Doppler bandwidth, and those skilled in synthetic aperture radar signal processing can clearly understand the factors affecting the Doppler bandwidth. The target's tangential velocity, the radar signal accumulation time, and the carrier frequency all affect the size of the Doppler bandwidth. In this embodiment, Δf is selected as half of the target's Doppler bandwidth (0.2 times the bandwidth to half the bandwidth are all possible ranges for Δf).

[0089] S107 uses the high-frequency component and the low-frequency component after frequency shifting to estimate the Doppler modulation frequency of the received signal, and obtains the Doppler modulation frequency of the target.

[0090] Specifically, in step S107, the Doppler modulation frequency of the received signal is estimated using the high-frequency component and the low-frequency component after frequency shifting to obtain the Doppler modulation frequency of the target, including the following steps S1071 to S1074.

[0091] S1071, calculate the first conjugate component of the low-frequency component after frequency shifting, and multiply the first conjugate component shown by the high-frequency component after frequency shifting to obtain the first result.

[0092] Specifically, by multiplying the conjugate of the frequency-shifted high-frequency component and the frequency-shifted low-frequency component, we obtain:

[0093]

[0094] S1072, Perform a Fourier transform on the first result to obtain the transformed data. Specifically, the transformed data is represented as follows:

[0095]

[0096] Where δ(·) is the impact function.

[0097] S1073, determine the column with the largest value in the transformation result to deduce the target Doppler frequency, and use the target Doppler frequency to determine the target's velocity. At this point, the target's Doppler modulation frequency γ can be deduced from the column position of the strongest value in the data. a , combined Determine the target's speed

[0098] S1074, since the background clutter does not exist the above non-radial motion speed, according to the motion speed, it is determined that the target exists and detection is completed.

[0099] The technical effects of the present application will be further described below in combination with simulation experiments:

[0100] 1. Simulation experiment conditions and contents:

[0101] (1a) Simulation experiment conditions:

[0102] CPU: Intel(R) Xeon(R) CPU E5-2637 v2 @ 3.50GHz;

[0103] Memory: 64.00GB;

[0104] Operating system: Windows 10 Education 64-bit operating system;

[0105] Simulation software: MATLAB R2021a;

[0106] Some parameters of the simulation experiment are shown in Table 1.

[0107] Table 1

[0108]

[0109] Simulation content:

[0110] The simulation verification is carried out using the technology of the present application, and a target with only radial velocity and a non-radial motion target are simulated in the scene. In the original range-Doppler profile of the radar, it is difficult to distinguish the two targets, and on the velocity-pseudospectrum, the targets can be detected according to the different tangential velocities of the targets.

[0111] Referring to Figure 4 the range-Doppler profile of the target corresponding distance unit, the target with only radial velocity produces a low-speed peak value, and the non-radial motion target of the radar produces a relatively high-speed peak value; referring to Figure 5 the velocity-pseudospectrum generated, Figure 4 on the spectrum domain, the characteristic spectrum diagram offset spectrum center generated by the non-radial motion target can be seen.

[0112] The above description is only a specific example of the present application and does not constitute any limitation on the present application. Obviously, for those skilled in the art, after understanding the content and principles of the present application, various modifications and changes in form and details can be made without departing from the principles and structures of the present application, but these modifications and changes based on the idea of the present application are still within the protection scope of the claims of the present application.

[0113] In a second aspect, the present application provides a device for detecting low-speed non-radial motion target using radar, comprising a signal compression module, a signal transformation module, a signal processing module, a signal searching module, a signal decomposition module, a signal frequency shifting module and an estimation module.

[0114] The signal compression module is configured to pulse-compress a received signal received by the radar to obtain a pulse-compressed signal.

[0115] The signal transformation module is configured to perform Fourier transform on the pulse-compressed signal along a direction bit to obtain a direction bit azimuth two-dimensional data.

[0116] The signal processing module is configured to select a one-dimensional Doppler data on a distance unit where the target is located in the direction bit azimuth to obtain processed data.

[0117] The signal searching module is configured to search for a plurality of Doppler center signals from the processed data.

[0118] The signal decomposition module is configured to perform signal frequency domain decomposition on each Doppler center signal to obtain a high-frequency component and a low-frequency component corresponding to each Doppler center signal.

[0119] The signal frequency shifting module is configured to perform frequency shifting on the high-frequency component and the low-frequency component corresponding to each Doppler center signal respectively to obtain a frequency-shifted high-frequency component and a frequency-shifted low-frequency component corresponding to each Doppler center signal.

[0120] The estimation module is configured to estimate a Doppler frequency of the received signal by using the frequency-shifted high-frequency component and the frequency-shifted low-frequency component to obtain a Doppler frequency of the target.

[0121] Although the present application provides the method operation steps as described in the embodiments or flowcharts, more or less operation steps can be included based on conventional or non-inventive labor. The order of steps listed in the embodiments is only one of the many step execution orders, and does not represent the only execution order. When the device or client product is executed in practice, the method order shown in the embodiments or the drawings can be executed in sequence or in parallel (for example, in a parallel processor or multi-thread processing environment).

[0122] The device or module illustrated in the above embodiments can be specifically implemented by a computer chip or entity, or by a product having certain functions. For the convenience of description, the above device is described as various modules respectively described in terms of functions. When the present application is implemented, the functions of the modules can be implemented in the same or multiple software and / or hardware. Of course, the modules implementing certain functions can also be implemented by multiple sub-modules or sub-units.

[0123] The methods, devices or modules described in the present application can be implemented in a computer readable program code manner, and the controller can be implemented in any appropriate manner, for example, the controller can take the form of a microprocessor or processor and a computer readable medium storing computer readable program code (such as software or firmware) executable by the (micro) processor, logic gates, switches, application specific integrated circuits (Application Specific Integrated Circuit, ASIC for short), programmable logic controllers and embedded microcontrollers, examples of the controller include but are not limited to the following microcontrollers: ARC 625D, Atmel AT91SAM, Microchip PIC18F26K20 and Silicone Labs C8051F320, and the memory controller can also be implemented as part of the control logic of the memory. Those skilled in the art also know that in addition to implementing the controller in a pure computer readable program code manner, the same function can also be implemented by logically programming the method steps in the form of logic gates, switches, application specific integrated circuits, programmable logic controllers and embedded microcontrollers. Therefore, such a controller can be considered as a hardware component, and the devices included therein for implementing various functions can also be regarded as structures within the hardware component. Alternatively, the devices for implementing various functions can be regarded as both software modules for implementing the method and structures within the hardware component.

[0124] Some of the modules in the device described in the present application can be described in the general context of computer-executable instructions, such as program modules. Generally, program modules include routines, programs, objects, components, data structures, classes, etc. that perform particular tasks or implement particular abstract data types. The present application can also be practiced in a distributed computing environment, in which tasks are performed by remote processing devices that are connected through a communication network. In a distributed computing environment, program modules can be located in both local and remote computer storage media, including storage devices.

[0125] The present application provides a server for completing low-speed non-radial motion target detection using radar, the server comprising a memory and a processor; the memory is used to store computer executable instructions; the processor is used to execute the computer executable instructions to realize the method for completing low-speed non-radial motion target detection using radar.

[0126] The present application provides a computer readable storage medium, the computer readable storage medium has executable instructions, and the computer executable instructions can realize the method for completing low-speed non-radial motion target detection using radar.

[0127] The storage medium described above includes, but is not limited to, a random access memory (RAM), a read-only memory (ROM), a cache, a hard disk drive (HDD), or a memory card. The storage medium can be used to store computer program instructions.

[0128] From the above description of the embodiments, those skilled in the art can clearly understand that the present application can be implemented by means of software and the necessary hardware. Based on such an understanding, the technical solutions of the present application, in essence or in the part that contributes to the prior art, can be embodied in the form of a software product or through the implementation of data migration. The computer software product can be stored in a storage medium, such as a ROM / RAM, a magnetic disk, an optical disk, etc., and includes a plurality of instructions for causing a computer device (which can be a personal computer, a mobile terminal, a server, or a network device, etc.) to execute the method described in each embodiment or some part of the embodiments of the present application.

[0129] The embodiments in the specification are described in a progressive manner, and the same or similar parts between the embodiments can be referred to each other. Each embodiment mainly describes the difference from other embodiments. The whole or part of the present application can be used in many general or special computer system environments or configurations. For example: personal computers, server computers, handheld devices or portable devices, tablet devices, mobile communication terminals, multi-processor systems, microprocessor-based systems, programmable electronic devices, network PCs, small computers, large computers, distributed computing environments including any of the above systems or devices, etc.

[0130] The above embodiments are only used to illustrate the technical solutions of the present application, and are not limited to the present application. Although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that the technical solutions recorded in the foregoing embodiments can be modified, or some or all of the technical features can be replaced by equivalents. The modification or replacement does not make the essence of the corresponding technical solution deviate from the scope of the technical solutions of the present application.

Claims

1. A method for detecting low-speed non-radial moving targets using radar, characterized in that, include: The received signal from the radar is pulse-compressed to obtain a pulse-compressed signal; The pulse compression signal is subjected to a Fourier transform along the azimuth direction to obtain azimuth-oriented two-dimensional data; the azimuth-oriented two-dimensional data is represented as: ; in, , Indicates the Doppler modulation frequency of the target ; Doppler frequency; The time series is sampled by the radar receiver; The delay time between the radar signal being reflected by the target and being received by the receiver; Represents the imaginary unit; Pi; The center wavelength of the radar transmitted signal; Let the initial position coordinates of the target be... The target speed of motion; This is a time sequence of pulses transmitted by the radar transmitter. Multiple one-dimensional Doppler data points are extracted from the distance cell where the target is located in the azimuth direction to obtain the processed dataset. For each processed data point in the processed dataset, a Doppler center signal search is performed to obtain a Doppler center signal set; the Doppler center signal is represented as: ； in, Indicates the Doppler values ​​used in the traversal search; Indicates a constant. ; Perform frequency domain decomposition on each Doppler center signal in the Doppler center signal set to obtain the high-frequency component and low-frequency component corresponding to each Doppler center signal; The high-frequency and low-frequency components corresponding to each Doppler center signal are frequency-shifted respectively to obtain the frequency-shifted high-frequency and low-frequency components corresponding to each Doppler center signal. The Doppler modulation frequency of the received signal is estimated by using the high-frequency component and the low-frequency component after frequency shifting, and the Doppler modulation frequency of the target is obtained.

2. The method for detecting low-speed non-radial moving targets using radar according to claim 1, characterized in that, The pulse compression signal is represented as: in, The bandwidth of the transmitted signal; The time series is sampled by the radar receiver; This is a time sequence of pulses transmitted by the radar transmitter. The delay time between the radar signal being reflected by the target and being received by the receiver; The relative distance between the target and the radar; Let the initial position coordinates of the target be... The target speed of motion; c The speed of light; Represented by natural constant An exponential function with base 0; Represents the imaginary unit; The center wavelength of the radar transmitted signal; Pi is the mathematical constant of a circle.

3. The method for detecting low-speed non-radial moving targets using radar according to claim 1, characterized in that, The step of performing frequency domain decomposition on each Doppler center signal to obtain the high-frequency and low-frequency components corresponding to each Doppler center signal includes: Each Doppler center signal is filtered using a high-pass filter and a low-pass filter to obtain the high-frequency and low-frequency components corresponding to each Doppler center signal.

4. The method for detecting low-speed non-radial moving targets using radar according to claim 1, characterized in that, The step of estimating the Doppler modulation frequency of the received signal using the frequency-shifted high-frequency component and the frequency-shifted low-frequency component to obtain the Doppler modulation frequency of the target includes: Calculate the first conjugate component of the low-frequency component after frequency shifting, and multiply the first conjugate component by the high-frequency component after frequency shifting to obtain the first result; Perform a Fourier transform on the first result to obtain the transformed data; The target Doppler frequency is retrieved from the column with the largest value in the transformed data, and the target velocity is determined using the target Doppler frequency. Based on the speed of movement, the presence of the target is determined and the detection is completed.

5. The method for detecting low-speed non-radial moving targets using radar according to claim 1, characterized in that, The processed data is represented as follows: in, Indicates the Doppler modulation frequency of the target; Indicates the Doppler frequency; Indicates a constant. .

6. A device for detecting low-speed non-radial moving targets using radar, characterized in that, include: The signal compression module is used to compress the received signal from the radar to obtain a pulse compressed signal. The signal transformation module is used to perform a Fourier transform on the pulse compressed signal along the direction position to obtain two-dimensional azimuth data; the two-dimensional azimuth data is represented as: ； in, , Indicates the Doppler modulation frequency of the target ; Doppler frequency; The time series is sampled by the radar receiver; The delay time between the radar signal being reflected by the target and being received by the receiver; Represents the imaginary unit; Pi; The center wavelength of the radar transmitted signal; Let the initial position coordinates of the target be... The target speed of motion; This is a time sequence of pulses transmitted by the radar transmitter. The signal processing module is used to extract one-dimensional Doppler data from the distance cell where the target is located in the azimuth direction to obtain processed data; The signal search module is used to search for Doppler center signals in the processed data to obtain multiple Doppler center signals; the Doppler center signals are represented as follows: ； in, Indicates the Doppler values ​​used in the traversal search; Indicates a constant. ; The signal decomposition module is used to perform frequency domain decomposition on each Doppler center signal to obtain the high-frequency and low-frequency components corresponding to each Doppler center signal. The signal frequency shifting module is used to perform frequency shifting processing on the high-frequency component and low-frequency component corresponding to each Doppler center signal, so as to obtain the frequency-shifted high-frequency component and frequency-shifted low-frequency component corresponding to each Doppler center signal. An estimation module is used to estimate the Doppler modulation frequency of the received signal using the frequency-shifted high-frequency component and the frequency-shifted low-frequency component, so as to obtain the Doppler modulation frequency of the target.

7. A server that uses radar to detect low-speed non-radial moving targets, characterized in that, Including memory and processor; The memory is used to store computer-executable instructions; The processor is configured to execute the computer-executable instructions to implement the method for detecting low-speed non-radial moving targets using radar as described in any one of claims 1-5.

8. A computer-readable storage medium, characterized in that, The computer-readable storage medium has executable instructions, and when the computer executes the executable instructions, it can implement the method for detecting low-speed non-radial moving targets using radar as described in any one of claims 1-5.

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