A radar monopulse three-dimensional direction finding method and system based on a cross antenna array

Abstract

The application discloses a radar single-pulse three-dimensional direction-finding method and system based on a cross antenna array. The method comprises the following steps: firstly, M times of fast snapping are performed on a current frame signal in an intermediate frequency signal obtained by frequency reduction, and FFT transformation is performed on a single-frame east-west processing data vector and a single-frame south-north processing data vector obtained by the fast snapping, respectively, to determine positions of amplitude spectrum peaks; and then, based on the positions of the amplitude spectrum peaks, an echo incidence angle of the single frame signal is determined; and then, fast snapping and processing are continuously performed on a next frame signal until the frame number of the processed signal reaches a frame length of the frame processing. The three-dimensional direction-finding method based on the cross antenna array can realize single-pulse direction-finding on the basis of noise suppression capability of quasi matching reception, and utilizes accumulation of multiple fast snapping data, so that high measurement precision is realized under a low signal-to-noise ratio, and the calculation complexity is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of radar detection, and particularly to a radar monopulse three-dimensional direction finding method and system based on a cross antenna array. BACKGROUND

[0002] In order to determine the spatial position of a target, the radar not only needs to determine the distance of the target, but also needs to determine the direction of the target, i.e. to determine the angular coordinates of the target, including the azimuth angle and the elevation angle of the target. Commonly used radar angle measurement methods include: amplitude method and phase method.

[0003] Amplitude method direction finding is based on the principle that the voltage amplitude induced on a directional antenna has a certain directional characteristic, and when the antenna rotates or is equivalent to rotating, the output voltage amplitude changes according to the polar pattern. Therefore, amplitude method direction finding is also called polar pattern direction finding. Amplitude method direction finding can be further divided into three categories: minimum signal method direction finding, maximum signal method direction finding, and amplitude comparison method direction finding. Minimum signal method direction finding is also called small sound point direction finding or "silence point" direction finding. It requires the polar pattern of the directional antenna to have one or more zero receiving points. When direction finding, the antenna is rotated. When the output signal of the direction finder is at a minimum value or is a small sound point (silence point) in hearing, it indicates that the zero receiving point of the polar pattern of the antenna is aligned with the direction of arrival of the wave. According to the angle of the antenna at this time, the direction of arrival value of the target signal can be determined. Since the strength of the output signal of the antenna changes sharply near the zero receiving point of the polar pattern, a small angle of rotation of the antenna can cause a large change in the amplitude of the signal. Therefore, the direction finding accuracy is much higher than that of maximum signal method direction finding; however, the reduction in signal-to-noise ratio near the minimum value of the signal will slightly reduce the direction finding accuracy. Maximum signal method direction finding requires the antenna to have a sharp directional characteristic. When direction finding, the antenna is rotated. When the output of the direction finder reaches a maximum signal value, it indicates that the main lobe of the polar pattern of the antenna is pointing to the direction of arrival of the wave. According to the pointing direction of the main lobe of the antenna at this time, the direction of arrival value of the target signal can be determined. Since the direction finding degree is obtained when the received signal of the antenna is at a maximum value, it has the ability to direction find weak signals, but the main disadvantage is that the direction finding accuracy is low. Because the polar pattern of the antenna changes slowly near the maximum value, a large angle of rotation (10% to 25% of the half-power point beam width) of the antenna is required to measure the significant change in the output voltage. Amplitude comparison method direction finding uses the ratio of the amplitudes of the voltages induced by the incoming signal on two antennas with the same structure and electrical properties, i.e., the intersection point characteristic of the two polar patterns, to complete the direction finding task. If the directional antenna is a strong directional antenna, then amplitude comparison method direction finding can be performed by comparing whether the signals output by the two antennas are equal, which is also called equal signal method direction finding. If the antenna has a slight rotation at this time, there will be a large difference in the amplitudes of the voltages output by the two antennas. Therefore, it has a high direction finding accuracy, just like minimum signal method direction finding, and also has a high direction finding receiving sensitivity because it uses the main lobe of the polar pattern to direction find. If the antenna is an "8" shaped directional antenna, then the ratio of the voltages output by the two antennas needs to be calculated to complete the direction finding task.

[0004] Phase direction finding is to measure the phase difference between the induced voltages on each antenna element in the direction finding antenna system. The induced voltages on each antenna element have the same amplitude, but due to the different locations of each antenna element, the paths of the wave propagation are different, resulting in different propagation times, and finally forming the phase difference between the induced voltages. In the actual application of the direction finding method, the interferometer direction finding, Doppler direction finding and time difference direction finding all belong to the category of phase direction finding. Considering Figure 1 The receiving voltages of the four antenna elements uniformly distributed on the circular array are

[0005]

[0006] The phase differences formed when the incident wave reaches the NS antenna pair and the EW antenna pair are respectively:

[0007]

[0008]

[0009] Since Therefore, the azimuth angle is:

[0010]

[0011] The elevation angle is:

[0012]

[0013] Phase direction finding requires channel amplitude and phase mismatch correction for multiple receiving channels, has high computational complexity, complex equipment, and requires high signal-to-noise. SUMMARY

[0014] The purpose of the present application is to provide a radar single pulse three-dimensional direction finding method and system based on a cross antenna array, to achieve high measurement accuracy at a lower signal-to-noise ratio, and to reduce the complexity of calculation.

[0015] To achieve the above purpose, the present application provides the following scheme:

[0016] A radar single pulse three-dimensional direction finding method based on a cross antenna array, the method comprising the following steps:

[0017] Obtaining the echo signal reflected by the target object received by the cross antenna array, and reducing the frequency of the echo signal to intermediate frequency to obtain an intermediate frequency signal;

[0018] M times of the current frame signal in the intermediate frequency signal are snapped to obtain a single frame east-west processing data vector and a single frame south-north processing data vector;

[0019] performing FFT (Fast Fourier Transform) transform on the single-frame east-west processing data vector and the single-frame north-south processing data vector respectively to determine a position of an amplitude spectrum peak of the single-frame east-west processing data vector and a position of an amplitude spectrum peak of the single-frame north-south processing data vector;

[0020] determining an echo incidence angle of the single-frame signal based on the position of the amplitude spectrum peak of the single-frame east-west processing data vector and the position of the amplitude spectrum peak of the single-frame north-south processing data vector; the echo incidence direction includes an incidence azimuth angle and an incidence elevation angle;

[0021] taking a next frame signal of the current frame signal in the intermediate frequency signal as a new current frame signal, and returning to the step of performing M times of fast sampling on the current frame signal in the intermediate frequency signal to obtain the single-frame east-west processing data vector and the single-frame north-south processing data vector until the frame number of the processed signal reaches the frame length of the frame-by-frame processing;

[0022] determining the direction of the target object based on the echo incidence angle of each frame signal.

[0023] Optionally, the method further includes:

[0024] determining the frame length Z of the frame-by-frame processing as follows: wherein c is the speed of light.

[0025] determining the fast sampling interval S as follows: T S T = N*d / c; wherein N is the number of single-column array elements of the cross antenna array, and d is the distance between adjacent array elements of the cross antenna array.

[0026] determining the number M of fast sampling as follows: wherein floor(·) represents a floor function.

[0027] Optionally, the intermediate frequency signal satisfies the following condition:

[0028]

[0029] wherein f m is the frequency of the intermediate frequency signal, d is the distance between adjacent array elements of the cross antenna array, and c is the speed of light.

[0030] Optionally, the method of determining the echo incidence angle of the single-frame signal based on the position of the amplitude spectrum peak of the single-frame east-west processing data vector and the position of the amplitude spectrum peak of the single-frame north-south processing data vector specifically includes:

[0031] The single-frame east-west echo coefficient and the single-frame north-south echo coefficient are respectively calculated based on a position of a peak of an amplitude spectrum of the single-frame east-west processing data vector and a position of a peak of an amplitude spectrum of the single-frame north-south processing data vector.

[0032]

[0033] wherein A EWZ and A NSZ are respectively the single-frame east-west echo coefficient and the single-frame north-south echo coefficient, I EWZ is the position of the peak of the amplitude spectrum of the single-frame east-west processing data vector, I NSZ is the position of the peak of the amplitude spectrum of the single-frame north-south processing data vector, c is the speed of light, f m is the frequency of the intermediate frequency signal, M is the number of snapshots, N is the number of single-column elements of the cross antenna array, and d is the distance between adjacent elements of the cross antenna array; K EW and K NS are respectively a compensation coefficient of east-west data processing and a compensation coefficient of north-south data processing.

[0034] The echo incidence angle of the single-frame signal is calculated based on the single-frame east-west echo coefficient and the single-frame north-south echo coefficient.

[0035]

[0036] wherein, and are respectively the incidence azimuth angle and the incidence elevation angle of the single-frame signal.

[0037] A radar single-pulse three-dimensional direction finding system based on a cross antenna array, the system is applied to the method, the system comprises:

[0038] A signal acquisition module is configured to acquire a return signal of a target object received by a cross antenna array, and to down-convert the return signal to an intermediate frequency to obtain an intermediate frequency signal.

[0039] A snapshot module is configured to perform M times of snapshots on a current frame signal in the intermediate frequency signal to obtain a single-frame east-west processing data vector and a single-frame north-south processing data vector.

[0040] A position determination module is configured to perform FFT transformation on the single-frame east-west processing data vector and the single-frame north-south processing data vector respectively to determine a position of a peak of an amplitude spectrum of the single-frame east-west processing data vector and a position of a peak of an amplitude spectrum of the single-frame north-south processing data vector.

[0041] The echo incidence angle determination module is configured to determine the echo incidence angle of the single frame signal based on the position of the amplitude spectrum peak of the single frame east-west processing data vector and the position of the amplitude spectrum peak of the single frame north-south processing data vector.

[0042] The return module is configured to take the next frame signal of the current frame signal in the intermediate frequency signal as a new current frame signal, call the fast sampling module until the frame number of the processed signal reaches the frame length of the frame-by-frame processing.

[0043] The target object direction determination module is configured to determine the direction of the target object based on the echo incidence angle of each frame signal.

[0044] An electronic device includes a memory, a processor, and a computer program stored on the memory and executable on the processor, and the processor implements the method described above when executing the computer program.

[0045] A computer readable storage medium has a computer program stored thereon, and the computer program implements the method described above when executed.

[0046] According to the specific embodiments of the present application, the following technical effects are achieved:

[0047] The present application discloses a radar single-pulse three-dimensional direction finding method and system based on a cross antenna array, which comprises the following steps: obtaining the echo signal reflected by a target object received by the cross antenna array, and reducing the frequency of the echo signal to an intermediate frequency to obtain an intermediate frequency signal; performing M times of fast sampling on the current frame signal in the intermediate frequency signal to obtain a single frame east-west processing data vector and a single frame north-south processing data vector; performing FFT transformation on the single frame east-west processing data vector and the single frame north-south processing data vector respectively to determine the position of the amplitude spectrum peak of the single frame east-west processing data vector and the position of the amplitude spectrum peak of the single frame north-south processing data vector; determining the echo incidence angle of the single frame signal based on the position of the amplitude spectrum peak of the single frame east-west processing data vector and the position of the amplitude spectrum peak of the single frame north-south processing data vector; taking the next frame signal of the current frame signal in the intermediate frequency signal as a new current frame signal, returning to the step of performing M times of fast sampling on the current frame signal in the intermediate frequency signal to obtain a single frame east-west processing data vector and a single frame north-south processing data vector until the frame number of the processed signal reaches the frame length of the frame-by-frame processing; and determining the direction of the target object based on the echo incidence angle of each frame signal. The three-dimensional direction finding method based on the cross antenna array can realize single-pulse direction finding on the basis of the noise suppression capability of the approximate matching reception, and utilizes the accumulation of multiple fast sampling data to realize high measurement accuracy at a low signal-to-noise ratio and reduce the complexity of the calculation. BRIEF DESCRIPTION OF DRAWINGS

[0048] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed in the embodiments. Obviously, the drawings described below only illustrate some of the embodiments of the present application, and other drawings can be obtained by those of ordinary skill in the art without any creative effort based on these drawings.

[0049] Figure 1 A schematic diagram of echo signal incident to a four-element antenna array in the background art of the present application;

[0050] Figure 2 A schematic diagram of echo signal incident to a cross antenna array provided by the embodiments of the present application;

[0051] Figure 3 A flowchart of a radar monopulse three-dimensional direction finding method based on a cross antenna array provided by the embodiments of the present application;

[0052] Figure 4 A schematic diagram of angle estimation error under different signal-to-noise ratios provided by the embodiments of the present application. DETAILED DESCRIPTION

[0053] 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 only some 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 of ordinary skill in the art without any creative effort fall within the scope of protection of the present application.

[0054] The purpose of the present application is to provide a radar monopulse three-dimensional direction finding method and system based on a cross antenna array, so as to achieve higher measurement accuracy under lower signal-to-noise ratio and reduce the complexity of calculation.

[0055] In order to make the above-mentioned purposes, features and advantages of the present application more apparent and easy to understand, the present application will be further described in detail below with reference to the drawings and specific embodiments.

[0056] Embodiment 1

[0057] The embodiments of the present application provide a radar monopulse three-dimensional direction finding method based on a cross antenna array. The three-dimensional direction finding in the embodiments of the present application refers to two three-dimensional solid incident angles, i.e. azimuth angle and pitch angle. For two-dimensional direction finding, there is only one incident angle, i.e. azimuth angle or pitch angle. The method provided by the embodiments of the present application can achieve monopulse direction finding on the basis of approximating the noise suppression capability of received signals, and the calculation complexity is about O(NlogN), where N is the number of single-column array elements of the cross antenna array. The embodiments of the present application adopt an N×N cross antenna array, such as Figure 2The method is shown in the figure and is realized in a digital signal processing manner.

[0058] As shown in the figure, the method provided by the embodiment of the application comprises the following steps: Figure 3

[0059] Step 301, determining a frame length Z of a frame processing of a received echo signal, a snapshot interval S T , and a snapshot number M of a single frame.

[0060] In actual application, a pulse repetition period Q is generally much larger than a pulse width T. That is, if the received echo signal is processed according to the entire pulse repetition period, a calculation amount will be too large. The radar measures a distance by measuring a pulse time delay, and the pulse repetition period corresponds to a maximum unambiguous distance, therefore, the frame length Z can also be measured by the distance. From Figure 4 It can be seen that increasing the processing frame length does not necessarily improve the direction finding precision. Therefore, the processing frame length can be determined by a time length corresponding to a 10-kilometer detection range, that is,

[0061]

[0062] In the formula, c represents a light speed. According to a distance d between adjacent elements and a single array element number N, the snapshot interval S T and the snapshot number M can be determined by the following formula:

[0063] S T =N*d / c

[0064]

[0065] In the formula, floor(·) represents a floor function.

[0066] Step 302, transmitting a pulse signal, receiving an echo signal, and down-converting the echo signal to an intermediate frequency f m . To ensure that a spectrum is not mixed, it is generally required to ensure that

[0067]

[0068] Step 303, performing M times of snapshot sampling on the intermediate frequency signals output by the elements with a snapshot interval S T , to obtain a frame of to-be-processed data, that is, a total time of about (M-1)·S T is required for a frame of data collection. One snapshot data of the N×N cross antenna array is N data in the north-south direction and N data in the east-west direction, that is,

[0069]

[0070] In the formula, s EW,n represents received data of the nth element in the east-west antenna array, s​NS,n Let the received data of the nth element in the north-south antenna array be denoted as s

[0071]

[0072] The single-frame processing data in the east-west direction and the north-south direction are obtained by sequentially rearranging the above M pairs of received sequences, respectively:

[0073]

[0074] In the formula, s EWZ , s NSZ are both 1xMN row vectors.

[0075] In step 304, the compensation coefficient K EW , K NS is set according to the search space range. Let α∈(70, 90), β∈(0, 20), then the compensation coefficient K EW , K NS can be set according to Table 1 and Table 2.

[0076] Table 1 Compensation coefficient for east-west data processing

[0077]

[0078]

[0079] Table 2 Compensation coefficient for north-south data processing

[0080] K NS ]]> β∈(0，5] β∈(5，10] β∈(10，15] β∈(15，20] α∈(70，75] 0.3004 0.2981 0.2936 0.2868 α∈(75，80] 0.2162 0.2146 0.2113 0.2064 α∈(80，85] 0.1304 0.1294 0.1274 0.1245 α∈(85，90] 0.0436 0.0432 0.0426 0.0416

[0081] In step 305, FFT is performed on s EWZ , s NSZ respectively, and the positions of the respective amplitude spectrum peaks searched are I EWZ , I NSZ , and then the coefficient is calculated:

[0082]

[0083] The echo incidence angle in the frame is finally estimated as:

[0084]

[0085] In step 306, return to step 303, collect the next frame of data to be processed for estimation, and sequentially frame process until the maximum detection distance (i.e., reach the Zth frame).

[0086] Example 2

[0087] Embodiment 2 of the present application is set as follows to illustrate the specific implementation mode and technical effect of the method provided in Embodiment 1 of the present application.

[0088] 1. Determine the frame length Z of the frame processing of the received echo signal, the snapshot interval S T , the number M of snapshots in which the single frame is located.

[0089] Suppose the speed of light is 3×10 8 meters per second, the processing frame length is determined by the time length corresponding to the 10-kilometer detection range, that is

[0090]

[0091] According to the adjacent element spacing d=0.1 and the number N=12 of single-column elements, the snapshot interval S T and the number M of snapshots can be determined as follows:

[0092] S T =4 nanoseconds

[0093] M=16666

[0094] 2. Transmit the pulse signal, receive the target echo, and down-convert the echo signal to the intermediate frequency f m =50 MHz.

[0095] 3. Perform M=16666 snapshot samplings on the intermediate frequency signals output by each element to obtain a frame of data to be processed s EWZ , s NSZ , which are both 1×199992 row vectors.

[0096] 4. According to the search space range α∈(80, 85] and β∈(10, 15], set the compensation coefficients as K EW =0.9679 and K NS =0.1274.

[0097] Perform FFT on s EWZ and s NSZ , search for the positions of the respective amplitude spectrum peaks as I EWZ =3326 and I NSZ =3334, then calculate the coefficients as A EWZ =0.9655 and A NSZ =0.1274, and finally estimate the echo incidence angle in the frame as: The above estimation result is α=82, β=13, and the single estimation result under the signal-to-noise ratio of 10 decibels. Figure 4For alpha=82, beta=13, the root mean square error of 100 simulation results under each signal-to-noise ratio in the range of [-25, 20], it can be seen that the application still has high estimation accuracy at lower signal-to-noise ratio.

[0098] Embodiment 3

[0099] A radar monopulse three-dimensional direction finding system based on a cross antenna array, the system is applied to the method, the system comprises:

[0100] A signal acquisition module is configured to acquire echo signals reflected by a target object received by the cross antenna array, and to down-convert the echo signals to intermediate frequency to obtain intermediate frequency signals.

[0101] A fast sampling module is configured to perform M times of fast sampling on a current frame of the intermediate frequency signals to obtain a single-frame east-west processing data vector and a single-frame north-south processing data vector.

[0102] An amplitude spectrum peak position determination module is configured to perform FFT transformation on the single-frame east-west processing data vector and the single-frame north-south processing data vector respectively to determine a position of an amplitude spectrum peak value of the single-frame east-west processing data vector and a position of an amplitude spectrum peak value of the single-frame north-south processing data vector.

[0103] An echo incidence angle determination module is configured to determine an echo incidence angle of a single frame of signals based on the position of the amplitude spectrum peak value of the single-frame east-west processing data vector and the position of the amplitude spectrum peak value of the single-frame north-south processing data vector.

[0104] A return module is configured to take a next frame of the current frame of the intermediate frequency signals as a new current frame of signals, and to call the fast sampling module until the frame number of the processed signals reaches a frame length of the frame processing.

[0105] A target object direction determination module is configured to determine a direction of the target object based on the echo incidence angle of each frame of signals.

[0106] The system provided by Embodiment 3 has similar working principles and beneficial effects to the method in Embodiment 1, and thus will not be described in detail here, and the specific content can be referred to the introduction of the method embodiment.

[0107] Embodiment 4

[0108] An electronic device includes a memory, a processor, and a computer program stored in the memory and executable on the processor, and the processor executes the computer program to implement the method.

[0109] In addition, the computer program in the memory described above is realized in the form of a software function unit and sold or used as an independent product, which can be stored in a computer readable storage medium. Based on such understanding, the technical solutions of the present application essentially or the part that contributes to the prior art or part of the technical solutions can be embodied in the form of a software product. The computer software product is stored in a storage medium, including a plurality of instructions to make a computer device (which can be a personal computer, a server or a network device, etc.) execute all or part of the steps of the method described in various embodiments of the present application. The foregoing storage medium includes: a U disk, a mobile hard disk, a read-only memory, a random access memory, a magnetic disk or an optical disk, and various media that can store program codes.

[0110] Embodiment 5

[0111] A computer readable storage medium having stored thereon a computer program which, when executed, implements the method described above.

[0112] A radar single-pulse three-dimensional direction finding method and system based on a cross antenna array, the method comprising the following steps: obtaining echo signals of a target object reflected by a cross antenna array, and down-converting the echo signals to intermediate frequency to obtain intermediate frequency signals; performing M times of fast sampling on a current frame signal in the intermediate frequency signals to obtain a single-frame east-west processing data vector and a single-frame north-south processing data vector; performing FFT transformation on the single-frame east-west processing data vector and the single-frame north-south processing data vector respectively to determine a position of an amplitude spectrum peak value of the single-frame east-west processing data vector and a position of an amplitude spectrum peak value of the single-frame north-south processing data vector; determining an echo incidence angle of a single frame signal based on the position of the amplitude spectrum peak value of the single-frame east-west processing data vector and the position of the amplitude spectrum peak value of the single-frame north-south processing data vector; taking a next frame signal of the current frame signal in the intermediate frequency signals as a new current frame signal, and returning to the step of performing M times of fast sampling on the current frame signal in the intermediate frequency signals to obtain a single-frame east-west processing data vector and a single-frame north-south processing data vector until the frame number of the processed signals reaches a frame length of the frame processing; and determining a direction of the target object based on the echo incidence angle of each frame signal. The three-dimensional direction finding method based on the cross antenna array can realize single-pulse direction finding on the basis of the noise suppression capability of quasi match reception, thereby realizing higher measurement accuracy under a lower signal-to-noise ratio and reducing the complexity of calculation.

[0113] The embodiments in the specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other. For the system disclosed in the embodiments, the description is relatively simple because it corresponds to the method disclosed in the embodiments. The relevant parts can be referred to the method part.

[0114] The principles and implementations of the present application are described in the specific examples herein, and the above examples are only used to help understand the method of the present application and its core idea; meanwhile, for those skilled in the art, according to the idea of the present application, there will be changes in the specific implementation and application range. In summary, the content of the specification should not be understood as a limitation of the present application.

Claims

1. A radar monopulse 3D direction finding method based on a cross antenna array, characterized in that, The method comprises the following steps: Obtaining echo signals reflected by the target object received by the cross antenna array and reducing the frequency of the echo signals to intermediate frequency to obtain intermediate frequency signals; M times of fast sampling are performed on the current frame signal in the intermediate frequency signal to obtain a single-frame east-west processing data vector and a single-frame north-south processing data vector; FFT transformation is performed on the single-frame east-west processing data vector and the single-frame north-south processing data vector respectively to determine the position of the amplitude spectrum peak value of the single-frame east-west processing data vector and the position of the amplitude spectrum peak value of the single-frame north-south processing data vector; Based on the position of the amplitude spectrum peak value of the single-frame east-west processing data vector and the position of the amplitude spectrum peak value of the single-frame north-south processing data vector, the echo incidence angle of the single-frame signal is determined; the echo incidence angle includes an incident azimuth angle and an incident elevation angle; The next frame signal of the current frame signal in the intermediate frequency signal is taken as a new current frame signal, and the step of "M times of fast sampling are performed on the current frame signal in the intermediate frequency signal to obtain a single-frame east-west processing data vector and a single-frame north-south processing data vector" is returned until the frame number of the processed signal reaches the frame length of the frame processing; Based on the echo incidence angle of each frame signal, the direction of the target object is determined.

2. The radar mono-pulse 3-D direction finding method based on cross antenna array according to claim 1, characterized in that, The step of obtaining echo signals reflected by the target object received by the cross antenna array and reducing the frequency of the echo signals to intermediate frequency to obtain intermediate frequency signals further comprises: Determining frame length for frame splitting processing Z For: ; wherein, c is the speed of light; Determining a snapshot interval S T To: S T N d c ; wherein N is the number of elements in a single column of the cross antenna array, d is the distance between adjacent elements of the cross antenna array.​​ Determining number of snaps M To: ; where floor( ) denotes a floor function.

3. The radar mono-pulse 3-D direction finding method based on cross antenna array of claim 1, wherein, The intermediate frequency signal satisfies the following conditions: ； wherein is the frequency of the intermediate frequency signal, is the distance between adjacent elements of the cross antenna array, is the speed of light.

4. The radar mono-pulse 3-D direction finding method based on cross antenna array of claim 1, wherein, The step of determining the echo incidence angle of the single-frame signal based on the position of the amplitude spectrum peak value of the single-frame east-west processing data vector and the position of the amplitude spectrum peak value of the single-frame north-south processing data vector specifically comprises: Based on the position of the amplitude spectrum peak value of the single-frame east-west processing data vector and the position of the amplitude spectrum peak value of the single-frame north-south processing data vector, the single-frame east-west echo coefficient and the single-frame north-south echo coefficient are calculated as follows: ； wherein, and are respectively a single-frame east-west echo coefficient and a single-frame north-south echo coefficient, is a single-frame east-west processed data vector amplitude spectrum peak position, is a single-frame north-south processed data vector amplitude spectrum peak position, is the speed of light, is the frequency of the intermediate frequency signal, M is the number of fast shots, N is the number of single-column array elements of the cross antenna array, d is the distance between adjacent array elements of the cross antenna array; and are respectively an east-west data processing compensation coefficient and a north-south data processing compensation coefficient; Based on the single-frame east-west echo coefficient and the single-frame north-south echo coefficient, the echo incidence angle of the single-frame signal is calculated as follows: ； wherein and are the incident azimuth and incident elevation angles, respectively, of the single frame signal.

5. A radar mono-pulse 3-D direction finding system based on a cross antenna array, characterized in that, The system is applied to the method of any one of claims 1-4, and the system comprises: A signal acquisition module is configured to obtain echo signals reflected by the target object received by the cross antenna array and reduce the frequency of the echo signals to intermediate frequency to obtain intermediate frequency signals; A fast sampling module is configured to perform M times of fast sampling on the current frame signal in the intermediate frequency signal to obtain a single-frame east-west processing data vector and a single-frame north-south processing data vector; An amplitude spectrum peak position determination module is configured to perform FFT transformation on the single-frame east-west processing data vector and the single-frame north-south processing data vector respectively to determine the position of the amplitude spectrum peak value of the single-frame east-west processing data vector and the position of the amplitude spectrum peak value of the single-frame north-south processing data vector; An echo incidence angle determination module is configured to determine the echo incidence angle of the single-frame signal based on the position of the amplitude spectrum peak value of the single-frame east-west processing data vector and the position of the amplitude spectrum peak value of the single-frame north-south processing data vector; the echo incidence angle includes an incident azimuth angle and an incident elevation angle; The returning module is configured to call the snapshot module with the next frame signal of the current frame signal in the intermediate frequency signal as a new current frame signal until the frame number of the processed signals reaches the frame length of the frame processing. The direction determining module of the target object is configured to determine the direction of the target object based on the echo incidence angle of each frame signal.

6. An electronic device, comprising: A computer program product comprising a memory, a processor, and a computer program stored on the memory and loadable on the processor, the processor implementing the method according to any one of claims 1 to 4 when executing the computer program.

7. A computer readable storage medium characterized in that, A computer program product comprising a memory, a processor, and a computer program stored on the memory and loadable on the processor, the processor implementing the method according to any one of claims 1 to 4 when executing the computer program.

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