Method and system for extracting three-dimensional information of variable-speed moving target

Abstract

The invention belongs to the technical field of radar detection, and discloses a variable motion target three-dimensional information extraction method and system, and the method comprises the steps: S1, transmitting a detection signal through a single-transmitting multi-receiving uniform circular array UCA antenna device, and building a target echo equation; s2, performing line frequency resolution and fast time domain fast Fourier transform on the echo of a single array element, removing a residual video phase, obtaining a one-dimensional range profile of a target, and extracting a rotation center coordinate; s3, performing line frequency tuning solution and fast time domain fast Fourier transform on total echoes of all array elements, removing a residual video phase term, and performing derivation to obtain a target Doppler frequency shift; and S4, extracting the rotation acceleration, the initial speed, the acceleration change coefficient, the rotation radius, the inclination angle, the rotation center and the coordinates of the moving target. According to the method, a trust domain dogleg algorithm is utilized to jointly solve a nonlinear equation set of target line and angle Doppler frequency shift, and the rotation radius, the inclination angle and the three-dimensional coordinates of the rotation center of the target are extracted.

Description

Technical Field

[0001] The present invention belongs to the field of radar detection technology, and in particular relates to a method and system for extracting three-dimensional information of a variable-speed moving target. Background Art

[0002] In recent years, with the gradual opening of my country's low-altitude flight field, the detection of low-altitude slow-moving targets has gradually become a major problem facing air defense security. Such targets are represented by drones, small helicopters and propeller aircraft. Usually, while the center of mass of such aircraft is moving horizontally, there are also rotations of micro-moving parts, such as the blades of propeller aircraft and the rotors of drones. These movements will modulate the radar echo signal within a certain line of sight, causing translational Doppler and micro-Doppler effects. Traditional radar detection systems mainly rely on the above two effects to obtain target motion information. However, due to the working principle of plane electromagnetic waves, when the target's movement is perpendicular to its propagation direction, the linear Doppler and other frequency shifts of the target echo will disappear, which means that the target cannot be identified. Unlike plane electromagnetic waves, vortex electromagnetic waves carrying orbital angular momentum have spiral phase wavefronts, which can provide new dimensions of information for target detection. Using its unique rotational Doppler frequency shift, information perpendicular and parallel to the propagation direction of the electromagnetic wave can be observed simultaneously.

[0003] In the specific application of vortex electromagnetic wave detection, some scholars have studied the parameter extraction of variable speed moving targets under axial incidence conditions. The literature (Detection of Uniformly Accelerated Spinning Target Based on OAM Beams) proposed an acceleration extraction algorithm based on Wigner Ville distribution for targets that only perform uniformly accelerated rotational motion, focusing on the analysis of factors affecting acceleration resolution. The literature (Detecting targetslongitudinal and angular accelerations based on vortex electromagnetic waves) proposed a multimodal method that can simultaneously extract the translational and rotational accelerations of compound motion targets. In addition, the literature (Parameter extraction of accelerated motion targets based on vortexelectromagnetic wave radar) improved the minimum acceleration resolution of detecting compound motion targets in the existing algorithm based on the non-differentiable point feature.

[0004] However, in actual detection, quasi-axial incidence is obviously very difficult for non-cooperative targets. In the study of non-quasi-axial incidence, the literature (Detection of rotational object in arbitrary position using vortex electromagnetic waves) successfully extracted the rotation radius and tilt angle of the target under arbitrary incidence conditions based on Hough transform, and realized the separation of linear Doppler shift and angular Doppler shift. On the other hand, the literature (Real micro-Doppler parameters extraction of spinning targets based on rotating interference antenna) proposed a method for extracting the real micro-motion parameters of rotating targets based on rotating interference antenna. By interfering with the micro-motion antenna and combining it with the orthogonal matching tracking algorithm, the rotation radius and tilt angle of the target were successfully obtained. However, the above studies are all based on the uniform rotational motion of the target, and the micro-motion parameters of the variable speed motion of the target cannot be extracted. In general, the existing non-quasi-axial incidence moving target detection technology is mainly based on uniform motion, and there are few detection technologies for targets with uniform acceleration or variable acceleration. However, in the actual movement of low-altitude slow targets, the targets have various variable speed motion states such as pitch, roll, and change of direction. At the same time, for non-cooperative targets, quasi-axial incidence is very difficult, and the coupling of linear and angular Doppler shifts of accelerated moving targets under non-quasi-axial incidence conditions is more complicated. In addition, most of the existing accelerated moving target detection technologies can only extract the target's acceleration, rotation radius and tilt angle, but cannot determine the target's rotation center and other position vectors. These limit the application of this technology in actual scenarios.

[0005] Through the above analysis, the problems and defects of the existing technology are: how to comprehensively utilize the linear Doppler shift and angular Doppler shift of the accelerated moving target under non-quasi-axial incidence conditions to detect the motion information of low-altitude slow targets and how to extract the position information and structural information of the target. Summary of the invention

[0006] In view of the problems existing in the prior art, the present invention provides a method and system for extracting three-dimensional information of a variable-speed moving target.

[0007] The present invention is implemented as follows: a method for extracting three-dimensional information of a variable speed moving target, comprising: S1, using a single-transmitter, multi-receiver uniform circular array (UCA) antenna device to transmit a detection signal and establish a mathematical equation that reflects the echo characteristics of the target object; S2, the echo signal received by a single array element is demodulated, fast Fourier transform is performed in the fast time domain, and the residual video phase is removed in order to analyze and extract the one-dimensional range image of the target object and further determine the center of rotation of the target object coordinate; S3, comprehensively processes the echo signals received by all array elements, and obtains information describing the Doppler frequency shift of the target object by demultiplexing, fast Fourier transform in fast time domain, removing residual video phase and derivative operation; S4, the acquired data accurately extracts the key parameters describing the rotational motion characteristics of the target object, including rotational acceleration, initial velocity, rotational acceleration variation coefficient, rotation radius, tilt angle, rotation center Three-dimensional coordinates.

[0008] Furthermore, the steps of setting the scene and establishing the coordinate system in the mathematical equation for establishing the echo characteristics of the target object specifically include: Three coordinate systems: radar coordinate system RCS, reference coordinate system RFS and target local coordinate system TCS; used to describe the relative position and direction of the target object and the radar system; Under the assumption that the target object rotates at variable speed around a fixed axis on a plane, a mathematical model of the target object's position in the radar coordinate system is established, and the speed, acceleration and other relevant dynamic parameters of the target motion are described in detail.

[0009] Further, the extracting of the one-dimensional range image of the target object specifically includes: Implement de-modulation, fast time domain Fast Fourier transform, and residual video phase removal processes to convert and analyze the received echo signal to accurately extract the one-dimensional distance information of the target object relative to the radar system; By analyzing the processed signal frequency peak, the rotation speed information of the target object is determined, laying the foundation for subsequent three-dimensional information extraction; The Doppler shift analysis steps specifically include: Perform de-modulation, fast Fourier transform in fast time domain, remove residual video phase, and obtain Doppler frequency shift information through derivation for distinguishing and analyzing the speed and direction changes of target objects. Segment and extract the Doppler shift caused by linear and angular changes of the target object, ensuring a comprehensive understanding of the target's motion state.

[0010] Furthermore, the step of accurately extracting key parameters describing the rotational motion characteristics of the target object specifically includes: By analyzing and processing the Doppler frequency shift data, the parameters describing the motion characteristics of the target object can be accurately extracted: rotation acceleration, initial velocity, acceleration variation coefficient, rotation radius, tilt angle, rotation center Three-dimensional coordinates; further analyze the extracted parameters to confirm the acceleration change trend, rotation radius and motion trajectory of the target object, and provide accurate data support for the three-dimensional information reconstruction of the moving target; The parameter estimation and calculation steps include: using mathematical models and algorithms to conduct in-depth analysis of the one-dimensional distance and Doppler frequency shift data obtained from the echo signal to obtain the rotation center coordinates and target object motion parameters; by integrating these parameters, a complete set of mathematical models is established to describe and predict the three-dimensional motion state of the target object, providing reliable target tracking and analysis capabilities for radar-based monitoring systems.

[0011] Furthermore, the method for extracting three-dimensional information of a variable speed moving target specifically includes: set up is the radar coordinate system, is the reference coordinate system, is the target local coordinate system; if the target is in the local coordinate system The rotation speed of the target on the plane Around the local coordinate system The axis moves at a variable speed, and the target rotation radius is , then its coordinates in the radar coordinate system are: (1); in Represents the reference coordinate system Axis and target local coordinate system The angle of the axis, Indicates time, Indicates the initial phase, Indicates the origin of the target's local coordinate system Coordinates in the radar coordinate system; and because the distance between the scattering point and the receiving antenna and the azimuth of the scattering point satisfy: (2); By detection signal and The total target echo can be obtained as: (3); in is an imaginary unit, is the modal order, is the scattering coefficient, is the number of antenna elements, , It represents the total time from the emission of electromagnetic waves to the return to the receiving antenna after the electromagnetic waves detect the target. is the carrier frequency of the transmitted signal, represents the wave number, is the modulation frequency of the transmitted signal, is the speed of light, For the first category Bessel function of order, is the radius of the UCA, is the elevation angle of the scattering point, is the pulse duration, slow time is the pulse interval time series, fast time is the pulse duration sequence, and the rect function is the rectangular window function; The echo of a single array element is demodulated, fast Fourier transform is performed in the fast time domain, and the residual video phase is removed to obtain the signal: (4); but ;Bundle Substituting into the above formula, we can get , and because , so when taking The midpoint between the first and second extreme points, that is When , we can get: (5); in is the echo received by a single antenna element, is the frequency corresponding to the peak value of the signal, Indicates the distance between the antenna and the target; By performing frequency modulation and fast Fourier transform in the time domain on the total echo signal received by all array elements, we can obtain: (6); in is an exponential function, For fast time The frequency corresponding to the echo after fast Fourier transform in the domain, , is the Fourier transform function, The properties of are similar to those of the symplectic function; After removing the residual video phase term, the total echo can be written as: (7); Derivative the total echo signal to extract the total Doppler shift Specifically include: (8); Then it is easy to get the Doppler frequency shift when emitting the vortex electromagnetic wave of the opposite mode: for: (9); in Indicates slow time The domain is used to differentiate the function. is the linear Doppler shift caused by the distance change along the radar line of sight, is the rotational Doppler shift caused by the azimuth change; Combining equations (8) and (9) yields: (10); Will Substitute the median of the first, second, and third extreme points and the first and second extreme points into You can get: (11); in Respectively The time corresponding to the first and second extreme points of express The time corresponding to the median between the first extreme point and the second extreme point of express The time corresponding to the median between the second extreme point and the third extreme point Simplifying formula (11) we can get: (12); in They represent the rough estimated values ​​of the target's initial rotation velocity, rotation acceleration, and rotation acceleration variation coefficient obtained by equation (11). Many time points are required, so the errors of multiple time points will be accumulated in the calculation, resulting in The estimation error of is large; however, from the third term of formula (12), we can see that In the solution of , what is subtracted is Multiply the cubic and quadratic terms of the time difference respectively, because The values ​​themselves are relatively small, so after being raised to a power they will become even smaller, thus weakening The estimated error of The impact of solving The estimation error is still small; represents the initial rotation speed of the target, represents the rotational acceleration, represents the coefficient of variation of rotational acceleration; Will Substitute the first, third, and fifth extreme points in the frequency shift curve into You can get: (13); in Respectively represent the time corresponding to the third and fifth extreme points, and Indicates that Substitution Then, using formula (13), we can get: (14); Among them, let the capital letters Expressing the rightmost equations of the three sub-equations in equation (14), we can further obtain: (15); At this time, we can use formula (14) and Get new and , respectively set to and ; Comparing formula (14) and formula (12), it can be seen that formula (14) relies on fewer time points, so the error caused by extracting time points has little impact on formula (14); therefore, and The error is less than and Error From the first term of formula (10), we can see that when When we take the first extreme value, we get: (16); in Indicates that Substitution The obtained frequency value; Substitute the median of the first and second extreme points, the median of the second and third extreme points, and the first and second extreme points into We can get: (17); in Respectively indicate that Substitution The obtained frequency value; then the obtained Substituting into equation (16) and equation (17) respectively, and using the trust region dogleg algorithm to solve the nonlinear equations, we can get The value of .

[0012] Further, the key parameter estimation step is specifically as follows: Step 1: De-interlace the echo of a single array element, perform fast Fourier transform in the time domain, remove the residual video phase, and obtain the rotation center The coordinate value of Step 2: Demodulate the echoes of all array elements, perform fast Fourier transform in the fast time domain, remove the residual video phase, and use the vortex electromagnetic waves of the opposite mode to separate the lines and angular Doppler shift; Step 3: extract the extreme points in the line Doppler frequency shift curve, and further use the obtained extreme points to find the median between two adjacent extreme points; then substitute the obtained extreme points and median into Get a rough estimate of the rotational acceleration, initial velocity, and acceleration change coefficient ; Step 4: Substitute the extreme points extracted in step 2 into Get The ratio of the extracted Get detailed estimates of rotational acceleration and acceleration variation coefficient ; Step 5: Substitute the extreme points and median values ​​extracted in step 2 into A nonlinear system of five equations is obtained, and then the estimated values ​​obtained in steps 3 and 4 are Substitute them into the above equations and extract them using the trust region dogleg algorithm The value of .

[0013] Another object of the present invention is to provide a system for extracting three-dimensional information of a speed-varying moving target for realizing the method for extracting three-dimensional information of a speed-varying moving target, comprising: A detection signal transmitting module is used to transmit a detection signal using a single-transmit multiple-receive uniform circular array (UCA) antenna device; The echo processing module is used to establish the target echo equation, and perform frequency modulation, fast Fourier transform in the fast time domain, and remove the residual video phase on the echo of a single array element and the total echo of all array elements; A Doppler frequency shift extraction module is used to derive the echo signal and extract the Doppler frequency shift; The moving target three-dimensional information extraction module extracts the moving target's rotational acceleration, initial velocity, acceleration change coefficient, rotation radius, tilt angle, and rotation center. coordinate.

[0014] Another object of the present invention is to provide a computer device, which includes a memory and a processor, wherein the memory stores a computer program, and when the computer program is executed by the processor, the processor executes the steps of the method for extracting three-dimensional information of a variable speed moving target.

[0015] Another object of the present invention is to provide a computer-readable storage medium storing a computer program, which, when executed by a processor, enables the processor to execute the steps of the method for extracting three-dimensional information of a variable-speed moving target.

[0016] Another object of the present invention is to provide an information data processing terminal, which is used to implement the three-dimensional information extraction system for variable speed moving targets.

[0017] First, in view of the technical problems existing in the above-mentioned prior art, some creative technical effects are brought about after solving the problems. The specific description is as follows: 1. The present invention derives the echo equation of a variable speed rotating target under non-quasi-axial incidence conditions, and obtains the intrinsic relationship between the Doppler frequency shift and the rotating target motion vector, position vector and structural information from the target echo equation.

[0018] 2. The present invention quantitatively analyzes the relationship between the Doppler effect and the rotational motion parameters of the target, and proposes a method for estimating the target motion parameters by the median and extreme values.

[0019] 3. The present invention uses the trust region dogleg algorithm to jointly solve the nonlinear equations of the target line and angular Doppler shift, and extracts the rotation radius, tilt angle, and three-dimensional coordinates of the rotation center of the target.

[0020] 4. The present invention further improves the minimum detectable target acceleration and is more in line with the actual low-altitude slow-speed target movement.

[0021] The present invention proposes a method for extracting three-dimensional motion information of a variable-speed moving target in a non-coordinated detection scenario, which greatly expands the detectable scenarios of low-altitude variable-speed moving targets.

[0022] Secondly, the method for extracting three-dimensional information of a speed-varying moving target provided by the present invention realizes accurate extraction of three-dimensional information of a speed-varying moving target.

[0023] First, in terms of method design, the present invention uses a single-transmitter multi-receiver uniform circular array UCA antenna device to transmit detection signals, and through a series of mathematical processing processes, such as decomposing line frequency modulation, extracting Doppler frequency shift extreme values, median information, etc., effectively extracts key information such as rotation acceleration, initial velocity, acceleration variation coefficient, rotation radius, tilt angle, rotation center, coordinates, etc. of the variable speed moving target. This method not only improves the accuracy of information extraction, but also reduces the complexity of the processing process, thereby improving processing efficiency.

[0024] Secondly, in the key steps, the present invention considers the target's motion state in the radar coordinate system and the distance and azimuth relationship between the scattering point and the receiving antenna by constructing the target echo equation, making the model closer to the actual physical process. At the same time, when extracting parameters such as rotational acceleration and initial velocity, the present invention uses optimization algorithms such as the trust region dogleg algorithm to further improve the accuracy and stability of parameter estimation.

[0025] In addition, the method of the present invention also has a wide range of application prospects. With the continuous development of radar technology, the demand for accurate detection and information extraction of variable speed moving targets is increasing. The method provided by the present invention can be applied not only to target detection and tracking in the military field, but also to the fields of drone monitoring, intelligent transportation systems, etc. in the civilian field, providing strong technical support for the development of related fields.

[0026] The present invention realizes the accurate extraction of three-dimensional information of variable speed moving targets by using a single-transmitter multi-receiver uniform circular array (UCA) antenna device to transmit detection signals and combining a series of mathematical processing processes. The method has the advantages of high processing efficiency, accurate information extraction, and a wide range of applications, and has made important contributions to the technological progress and application development in related fields.

[0027] Third, the present invention also has advantages and positive effects in terms of mathematical models and algorithms. Specifically: First, when processing the echo signal of a variable-speed moving target, the existing technology often finds it difficult to accurately extract the target's key parameters such as rotational acceleration, initial velocity, acceleration variation coefficient, etc. The present invention constructs a refined target echo equation and introduces demultiplexing, fast time domain fast Fourier transform, and residual video phase removal technology to effectively extract these key parameters from the echo signal, greatly improving the accuracy and reliability of parameter estimation.

[0028] Secondly, the present invention uses vortex electromagnetic waves of opposite modes to separate linear and angular Doppler shifts, further improving the accuracy of parameter estimation. Through this method, the Doppler shift information of the target can be more accurately identified and extracted, providing a more reliable data basis for subsequent parameter estimation.

[0029] In addition, the present invention also achieves accurate estimation of parameters such as rotational acceleration, initial velocity, acceleration variation coefficient, etc. by solving a series of nonlinear equations. The construction and solution process of these equations fully consider the complexity and nonlinear characteristics of the target motion state, thereby ensuring the accuracy and stability of parameter estimation.

[0030] The mathematical model and algorithm of the present invention have achieved remarkable technical progress in extracting three-dimensional information of variable speed moving targets, which not only improves the accuracy and reliability of parameter estimation, but also provides strong technical support for research and application in related fields. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments of the present invention. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0032] Figure 1 is a flow chart of a method for extracting three-dimensional information of a variable speed moving target provided by an embodiment of the present invention; Figure 2 It is a structural diagram of a system for extracting three-dimensional information of a variable speed moving target provided by an embodiment of the present invention; Figure 3 is a schematic diagram of the geometric relationship between the radar and the target provided by an embodiment of the present invention; Figure 4 The embodiment of the present invention provides Schematic diagram of the change curve; Figure 5 It is a slow time-distance image of a variable speed moving target provided by an embodiment of the present invention; Figure 6 is a schematic diagram of parameter extraction errors for different motion parameter settings provided by an embodiment of the present invention; Figure 7 It is a schematic diagram of parameter extraction error under different signal-to-noise ratio conditions provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0033] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0034] like Figure 1 As shown, the method for extracting three-dimensional information of a variable speed moving target provided by an embodiment of the present invention includes: S1, using a single-transmitter and multiple-receiver uniform circular array (UCA) antenna device to transmit detection signals and establish a target echo equation; S2, the echo signal received by a single array element is demodulated, fast Fourier transform is performed in the fast time domain, and the residual video phase is removed in order to analyze and extract the one-dimensional range image of the target object and further determine the rotation center of the target object. coordinate; S3, de-modulate the total echo signal received by all array elements, perform fast Fourier transform in the fast time domain, remove the residual video phase term, and then take the derivative to obtain the target Doppler shift; S4, accurately extract key parameters of the target object's rotational motion characteristics (such as motion vector, position vector and structural information), including rotational acceleration, initial velocity, acceleration change coefficient, rotation radius, tilt angle, rotation center Three-dimensional coordinates.

[0035] like Figure 2 As shown, the system for extracting three-dimensional information of a variable speed moving target provided by an embodiment of the present invention includes: A detection signal transmitting module is used to transmit a detection signal using a single-transmit multiple-receive uniform circular array (UCA) antenna device; The echo processing module is used to establish the target echo equation, and perform frequency modulation, fast Fourier transform in the fast time domain, and remove the residual video phase on the echo of a single array element and the total echo of all array elements; A Doppler frequency shift extraction module is used to derive the echo signal and extract the Doppler frequency shift; The moving target three-dimensional information extraction module extracts the moving target's rotational acceleration, initial velocity, acceleration change coefficient, rotation radius, tilt angle, and rotation center. coordinate.

[0036] The design scheme of the present invention is specifically as follows: The first step is to use a single-transmitter multi-receiver uniform circular array (UCA) antenna device to transmit the detection signal. The geometric relationship between the radar and the target is as follows: Figure 3 As shown, is the radar coordinate system, is the reference coordinate system, is the target local coordinate system; if the target is in the local coordinate system The rotation speed of the target on the plane Around the local coordinate system The axis moves at a variable speed, and the target rotation radius is , then its coordinates in the radar coordinate system are: (1); in Represents the reference coordinate system Axis and target local coordinate system The angle of the axis, Indicates time, Indicates the initial phase, Indicates the origin of the target's local coordinate system Coordinates in the radar coordinate system; and because the distance between the scattering point and the receiving antenna and the azimuth of the scattering point satisfy: (2); The second step is to establish the target echo equation and perform de-linear frequency modulation processing on the echo of a single array element and the total echo of all array elements. The total target echo can be obtained as: (3); in is an imaginary unit, is the modal order, is the scattering coefficient, is the number of antenna elements, , It represents the total time from the emission of electromagnetic waves to the return to the receiving antenna after the electromagnetic waves detect the target. is the carrier frequency of the transmitted signal, represents the wave number, is the modulation frequency of the transmitted signal, is the speed of light, For the first category Bessel function of order, is the radius of the UCA, is the elevation angle of the scattering point, is the pulse duration, slow time is the pulse interval time series, fast time is the pulse duration sequence, and the rect function is the rectangular window function; In the third step, the echo of a single array element is demodulated, fast Fourier transform is performed in the fast time domain, and the residual video phase is removed to obtain the signal: (4); but ;Bundle Substituting into the above formula, we can get , and because , so when taking The midpoint between the first and second extreme points, that is When , we can get: (5); in is the echo received by a single antenna element, is the frequency corresponding to the peak value of the signal, Indicates the distance between the antenna and the target; By performing frequency modulation and fast Fourier transform in the time domain on the total echo signal received by all array elements, we can obtain: (6); in is an exponential function, For fast time The frequency corresponding to the echo after fast Fourier transform in the domain, , is the Fourier transform function, The properties of are similar to those of the symplectic function; After removing the residual video phase term, the total echo can be written as: (7); Derivative the total echo signal to extract the total Doppler shift Specifically include: (8); Then it is easy to get the Doppler frequency shift when emitting the vortex electromagnetic wave of the opposite mode: for: (9); in Indicates slow time The domain is used to differentiate the function. is the linear Doppler shift caused by the distance change along the radar line of sight, is the rotational Doppler shift caused by the azimuth change; Combining equations (8) and (9) yields: (10); The fourth step is to extract the target's motion vector, position vector and structural information based on the relationship between the Doppler frequency shift and the speed-varying moving target parameters, including rotation acceleration, initial velocity, acceleration variation coefficient, rotation radius, tilt angle, rotation center, etc. coordinate.

[0037] From the first term of formula (10), we can get: Change periodically over time, such as Figure 4 As shown, Only The amplitude of The extreme value of The impact, therefore The extreme points of or ,when When taking the midpoint of two adjacent extreme points, ,in .

[0038] Will Substitute the median of the first, second, and third extreme points and the first and second extreme points into You can get: (11); in Respectively The time corresponding to the first and second extreme points of express The time corresponding to the median between the first extreme point and the second extreme point of express The time corresponding to the median between the second extreme point and the third extreme point Simplifying formula (11) we can get: (12); in They represent the rough estimated values ​​of the target's initial rotation velocity, rotation acceleration, and rotation acceleration variation coefficient obtained by equation (11). Many time points are required, so the errors of multiple time points will be accumulated in the calculation, resulting in The estimation error of is large; however, from the third term of formula (12), we can see that In the solution of , what is subtracted is Multiply the cubic and quadratic terms of the time difference respectively, because The values ​​themselves are relatively small, so after being raised to a power they will become even smaller, thus weakening The estimated error of The impact of solving The estimation error is still small; Will Substitute the first, third, and fifth extreme points in the frequency shift curve into You can get: (13); in Respectively represent the time corresponding to the third and fifth extreme points, and Indicates that Substitution Then, using formula (13), we can get: (14); Among them, let the capital letters Expressing the rightmost equations of the three sub-equations in equation (14), we can further obtain: (15); At this time, we can use formula (14) and Get new and , respectively set to and ; Comparing formula (14) and formula (12), it can be seen that formula (14) relies on fewer time points, so the error caused by extracting time points has little impact on formula (14); therefore, and The error is less than and Error From the first term of formula (10), we can see that when When we take the first extreme value, we get: (16); in Indicates that Substitution The obtained frequency value; Substitute the median of the first and second extreme points, the median of the second and third extreme points, and the first and second extreme points into We can get: (17); in Respectively indicate Substitution The obtained frequency value; then the obtained Substituting into equation (16) and equation (17) respectively, and using the trust region dogleg algorithm to solve the nonlinear equations, we can get The value of .

[0039] The key parameter estimation steps are as follows: Step 1: De-interlace the echo of a single array element, perform fast Fourier transform in the time domain, remove the residual video phase, and obtain the rotation center The coordinate value of Step 2: Demodulate the echoes of all array elements, perform fast Fourier transform in the fast time domain, remove the residual video phase, and use the vortex electromagnetic waves of the opposite mode to separate the lines and angular Doppler shift; Step 3: extract the extreme points in the line Doppler frequency shift curve, and further use the obtained extreme points to find the median between two adjacent extreme points; then substitute the obtained extreme points and median into Get a rough estimate of the rotational acceleration, initial velocity, and acceleration change coefficient ; Step 4: Substitute the extreme points extracted in step 2 into Get The ratio of the extracted Get detailed estimates of rotational acceleration and acceleration variation coefficient ; Step 5: Substitute the extreme points and median values ​​extracted in step 2 into A nonlinear system of five equations is obtained, and then the estimated values ​​obtained in steps 3 and 4 are Substitute them into the above equations and extract them using the trust region dogleg algorithm The value of .

[0040] Assuming that the target motion parameters are as shown in Table 1, the experimental results show that the estimated values ​​of the target's initial rotation velocity, acceleration, and acceleration variation coefficient are 119.640πrad / s², 59.780πrad / s², and 51.590πrad / s, respectively. Then, the above estimated values ​​are substituted into equations (16) and (17), and the trust region dogleg algorithm is used to solve the above equations. The solution is: The estimated values ​​are 0.304m, 0.524rad, 0.100m, and 0.202m respectively. Obviously, the maximum error of the above parameters is less than 3.2%. In addition, using step 2, we can get The estimated error is 0.11%.

[0041] Table 1 Related parameter settings Parameter name Parameter Value Carrier frequency 10 GHz OAM Mode 4 Coefficient of variation of rotational acceleration 50π rad / s² Rotational acceleration 60π rad / s² Initial rotation speed 120π rad / s Radius of rotation 0.3 m Center of rotation （0.1,0.2,29） Tilt Angle π / 6 rad In addition, when When changes, the corresponding parameter extraction error can be obtained as Figure 6 As shown. The experimental results show that when the rotation acceleration varies in the range of [0.1πrad / s², 127πrad / s²], the detection errors of each parameter are less than 5%. In addition, in order to study the impact of noise interference on the algorithm proposed in this invention, four groups of experiments with signal-to-noise ratios of 5dB, 10dB, 15dB, and 20dB were designed. Without loss of generality, 100 Monte Carlo experiments were conducted under each signal-to-noise ratio condition. Other parameter settings are shown in Table 1. The parameter extraction errors of each group of experiments are shown in Table 1. Figure 7 As shown. From the analysis of the figure, it can be seen that the influence of noise interference on the acceleration parameter extraction is relatively large. The analysis shows that this is because the noise will cause the time-frequency curve to jitter, affecting the distribution of the extreme point position, and further causing the acceleration extraction accuracy to decrease. At the same time, because RACC requires the largest number of extreme points, it is most affected by noise. It can be seen from the figure that when the signal-to-noise ratio is 5dB, except for the RACC estimation error of 11.4%, the estimation errors of other parameters are all less than 5.0%, which also verifies the robustness of the algorithm proposed in this invention.

[0042] An application embodiment of the present invention provides a computer device, which includes a memory and a processor. The memory stores a computer program. When the computer program is executed by the processor, the processor executes the steps of a method for extracting three-dimensional information of a variable-speed moving target.

[0043] An application embodiment of the present invention provides a computer-readable storage medium storing a computer program. When the computer program is executed by a processor, the processor executes the steps of a method for extracting three-dimensional information of a variable-speed moving target.

[0044] The application embodiment of the present invention provides an information data processing terminal, which is used to implement a three-dimensional information extraction system for a variable speed moving target.

[0045] The present invention can be applied to the detection of low, slow and small targets represented by drones, small helicopters, propeller aircraft, etc., and provide more parameter support for the identification of such targets. Two specific application examples are provided here to demonstrate the application value of the technology in actual scenarios.

[0046] Example 1: Air traffic monitoring In the field of air traffic monitoring, this technology can be used to track and evaluate the motion status of aircraft, especially accurate tracking under complex spatial dynamics.

[0047] 1. Scenario setting: Set up a single-transmitter, multiple-receiver UCA device near the airport and use the system to monitor aircraft taking off, landing, or flying around the airport.

[0048] 2. Data acquisition and processing: Collect echo signals reflected from different aircraft and extract the three-dimensional information of each aircraft, including position, speed, acceleration, rotation radius, etc., through the method proposed in this invention.

[0049] 3. Practical application: Through continuous monitoring, the aircraft's motion status and abnormal behavior can be evaluated in real time, providing important data support for aviation safety.

[0050] Example 2: Industrial robot motion monitoring In the field of industrial manufacturing, this technology can be used to monitor the dynamic movement of industrial robots, ensuring the precise operation of the robots and preventing potential failures.

[0051] 1. Scenario setting: Deploy a single-transmitter, multiple-receiver UCA device in a factory workshop to monitor industrial robots responsible for assembly, welding or handling.

[0052] 2. Data acquisition and processing: Collect the echo signals generated by the movement of each component of the robot, and use the method of the present invention to extract the detailed motion parameters of the robot, such as the rotation speed and acceleration of each joint.

[0053] 3. Practical application: Real-time acquisition of robot motion information helps optimize robot path planning, predict maintenance needs, and identify motion anomalies in advance, thereby improving production efficiency and equipment reliability.

[0054] In view of the problems existing in the prior art, the present invention provides a method and system for extracting three-dimensional information of a variable-speed moving target. The present invention is described in detail below in conjunction with the accompanying drawings.

[0055] It should be noted that the embodiments of the present invention can be implemented by hardware, software, or a combination of software and hardware. The hardware portion can be implemented using dedicated logic; the software portion can be stored in a memory and executed by an appropriate instruction execution system, such as a microprocessor or dedicated design hardware. A person of ordinary skill in the art will appreciate that the above-mentioned devices and methods can be implemented using computer executable instructions and / or contained in a processor control code, such as a carrier medium such as a disk, CD or DVD-ROM, a programmable memory such as a read-only memory (firmware), or a data carrier such as an optical or electronic signal carrier. Such code is provided on the carrier medium. The device and its modules of the present invention can be implemented by hardware circuits such as very large-scale integrated circuits or gate arrays, semiconductors such as logic chips, transistors, etc., or programmable hardware devices such as field programmable gate arrays, programmable logic devices, etc., can also be implemented by software executed by various types of processors, and can also be implemented by a combination of the above-mentioned hardware circuits and software, such as firmware.

[0056] The above description is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Any modification, equivalent substitution and improvement made by any technician familiar with the technical field within the technical scope disclosed by the present invention and within the spirit and principle of the present invention should be covered by the protection scope of the present invention.

Claims

1. A method for extracting three-dimensional information of a variable speed moving target, characterized in that: include: The detection signal is transmitted using a single-transmitter, multi-receiver uniform circular array (UCA) antenna device, and a mathematical equation reflecting the echo characteristics of the target object is established; The echo signal received by a single array element is demodulated, fast Fourier transformed in the fast time domain, and the residual video phase is removed to analyze and extract the one-dimensional range image of the target object and further determine the center of rotation of the target object. coordinate; Comprehensively process the echo signals received by all array elements, and obtain information describing the Doppler shift of the target object through demultiplexing, fast Fourier transform in fast time domain, removal of residual video phase and derivative operation; The acquired data can accurately extract the key parameters describing the rotational motion characteristics of the target object, including rotational acceleration, initial velocity, rotational acceleration variation coefficient, rotation radius, tilt angle, rotation center Three-dimensional coordinates.

2. The method for extracting three-dimensional information of a variable speed moving target according to claim 1, characterized in that: The steps of scene setting and coordinate system establishment in establishing a mathematical equation that reflects the echo characteristics of the target object specifically include: Three coordinate systems: radar coordinate system RCS, reference coordinate system RFS and target local coordinate system TCS; used to describe the relative position and direction of the target object and the radar system; Under the assumption that the target object rotates at variable speed around a fixed axis on a plane, a mathematical model of the target object's position in the radar coordinate system is established, and the speed, acceleration and other relevant dynamic parameters of the target motion are described in detail.

3. The method according to claim 1, characterized in that Extracting the one-dimensional range image of the target object specifically includes: Implement de-modulation, fast time domain Fast Fourier transform, and residual video phase removal processes to convert and analyze the received echo signal to accurately extract the one-dimensional distance information of the target object relative to the radar system; By analyzing the frequency peak of the processed signal, the rotation speed information of the target object is determined; The Doppler shift analysis steps specifically include: Perform de-modulation, fast Fourier transform in fast time domain, remove residual video phase, and obtain Doppler shift information by derivative for distinguishing and analyzing the speed and direction changes of target objects. Segment and extract the Doppler shift caused by linear and angular changes of the target object, ensuring a comprehensive understanding of the target's motion state.

4. The method according to claim 1, characterized in that The steps to accurately extract the key parameters that describe the rotational motion characteristics of the target object include: By analyzing and processing the Doppler frequency shift data, the parameters describing the motion characteristics of the target object can be accurately extracted: rotation acceleration, initial velocity, acceleration variation coefficient, rotation radius, tilt angle, rotation center Three-dimensional coordinates; The extracted parameters are further analyzed to confirm the acceleration change trend, rotation radius and motion trajectory of the target object, providing accurate data support for the three-dimensional information reconstruction of the moving target; The parameter estimation and calculation steps include: Mathematical models and algorithms are used to conduct in-depth analysis of the one-dimensional distance and Doppler frequency shift data obtained from the echo signal to obtain the rotation center coordinates and target object motion parameters; By integrating these parameters, a complete mathematical model is established to describe and predict the three-dimensional motion state of the target object, providing reliable target tracking and analysis capabilities for radar-based monitoring systems.

5. The method for extracting three-dimensional information of a variable speed moving target according to claim 1, characterized in that: The method for extracting three-dimensional information of a variable speed moving target specifically includes: set up is the radar coordinate system, is the reference coordinate system, is the target local coordinate system; if the target is in the local coordinate system The rotation speed of the target on the plane Around the local coordinate system The axis moves at a variable speed, and the target rotation radius is , then its coordinates in the radar coordinate system are: （1）； in Represents the reference coordinate system Axis and target local coordinate system The angle of the axis, Indicates time, Indicates the initial phase, Indicates the origin of the target's local coordinate system Coordinates in the radar coordinate system; and because the distance between the scattering point and the receiving antenna and the azimuth of the scattering point satisfy: （2）； By detection signal and The total target echo can be obtained as: （3）； in is an imaginary unit, is the modal order, is the scattering coefficient, is the number of antenna elements, , It represents the total time from the emission of electromagnetic waves to the return to the receiving antenna after the electromagnetic waves detect the target. is the carrier frequency of the transmitted signal, represents the wave number, is the modulation frequency of the transmitted signal, is the speed of light, For the first category Bessel function of order, is the radius of the UCA, is the elevation angle of the scattering point, is the pulse duration, slow time is the pulse interval time series, fast time is the pulse duration sequence, and the rect function is the rectangular window function; The echo of a single array element is demodulated, fast Fourier transform is performed in the fast time domain, and the residual video phase is removed to obtain the signal: （4）； but ;Bundle Substituting into the above formula, we can get , and because , so when taking The midpoint between the first and second extreme points, that is When , we can get: （5）； in is the echo received by a single antenna element, is the frequency corresponding to the peak value of the signal, Indicates the distance between the antenna and the target; By performing frequency modulation and fast Fourier transform in the time domain on the total echo signal received by all array elements, we can obtain: （6）； in is an exponential function, For fast time The frequency corresponding to the echo after fast Fourier transform in the domain, , is the Fourier transform function, The properties of are similar to those of the symplectic function; After removing the residual video phase term, the total echo can be written as: （7）； Derivative the total echo signal to extract the total Doppler shift Specifically include: （8）； Then it is easy to get the Doppler frequency shift when emitting the vortex electromagnetic wave of the opposite mode: for: （9）； in Indicates slow time The domain is used to differentiate the function. is the linear Doppler shift caused by the distance change along the radar line of sight, is the rotational Doppler shift caused by the azimuth change; Combining equations (8) and (9) yields: （10）； Will Substitute the median of the first, second, and third extreme points and the first and second extreme points into You can get: （11）； in Respectively The time corresponding to the first and second extreme points of express The time corresponding to the median between the first extreme point and the second extreme point of express The time corresponding to the median between the second extreme point and the third extreme point Simplifying formula (11), we can get: （12）； in They represent the rough estimated values ​​of the target's initial rotation velocity, rotation acceleration, and rotation acceleration variation coefficient obtained by equation (11). Many time points are required, so the errors of multiple time points will be accumulated in the calculation, resulting in The estimation error of is large; however, from the third term of formula (12), we can see that In the solution of , what is subtracted is Multiply the cubic and quadratic terms of the time difference respectively, because The values ​​themselves are relatively small, so after being raised to a power they will become even smaller, thus weakening The estimated error of The impact of solving The estimation error is still small; represents the initial rotation speed of the target, represents the rotational acceleration, represents the coefficient of variation of rotational acceleration, Will Substitute the first, third, and fifth extreme points in the frequency shift curve into You can get: （13）； in Respectively represent the time corresponding to the third and fifth extreme points, and Indicates that Substitution Then, using formula (13), we can get: （14）； Among them, let the capital letters Expressing the rightmost equations of the three sub-equations in equation (14), we can further obtain: （15）； At this time, we can use formula (14) and Get new and , respectively set to and ; Comparing formula (14) and formula (12), it can be seen that formula (14) relies on fewer time points, so the error caused by extracting time points has little impact on formula (14); therefore, and The error is less than and Error From the first term of formula (10), we can see that when When we take the first extreme value, we get: （16）； in Indicates that Substitution The obtained frequency value; Substitute the median of the first and second extreme points, the median of the second and third extreme points, and the first and second extreme points into We can get: （17）； in Respectively indicate that Substitution The obtained frequency value; then the obtained Substituting into equation (16) and equation (17) respectively, and using the trust region dogleg algorithm to solve the nonlinear equations, we can get The value of .

6. The method for extracting three-dimensional information of a variable speed moving target according to claim 4, characterized in that: The key parameter estimation steps are as follows: Step 1: De-interlace the echo of a single array element, perform fast Fourier transform in the time domain, remove the residual video phase, and obtain the rotation center The coordinate value of Step 2: Demodulate the echoes of all array elements, perform fast Fourier transform in fast time domain, remove residual video phase, and separate lines and angular Doppler shift using vortex electromagnetic waves of opposite modes; Step 3: extract the extreme points in the line Doppler frequency shift curve, and further use the obtained extreme points to find the median between two adjacent extreme points; then substitute the obtained extreme points and median into Get a rough estimate of the rotational acceleration, initial velocity, and acceleration change coefficient ; Step 4: Substitute the extreme points extracted in step 2 into Get The ratio of the extracted Get detailed estimates of rotational acceleration and acceleration variation coefficient ; Step 5: Substitute the extreme points and median values ​​extracted in step 2 into A nonlinear system of five equations is obtained, and then the estimated values ​​obtained in steps 3 and 4 are Substitute them into the above equations and extract them using the trust region dogleg algorithm The value of .

7. A system for extracting three-dimensional information of a variable speed moving target for implementing the method for extracting three-dimensional information of a variable speed moving target according to any one of claims 1 to 6, characterized in that: include: A detection signal transmitting module is used to transmit a detection signal using a single-transmit multiple-receive uniform circular array (UCA) antenna device; The echo processing module is used to establish the target echo equation, and perform frequency modulation, fast Fourier transform in the fast time domain, and remove the residual video phase on the echo of a single array element and the total echo of all array elements; A Doppler frequency shift extraction module is used to derive the echo signal and extract the Doppler frequency shift; The moving target three-dimensional information extraction module extracts the moving target's rotational acceleration, initial velocity, acceleration variation coefficient, rotation radius, tilt angle, and rotation center coordinates.

8. A computer device, comprising a memory and a processor, wherein the memory stores a computer program, and when the computer program is executed by the processor, the processor executes the steps of the method for extracting three-dimensional information of a speed-varying moving target as described in any one of claims 1 to 6.

9. A computer-readable storage medium storing a computer program, which, when executed by a processor, enables the processor to execute the steps of the method for extracting three-dimensional information of a speed-varying moving target as claimed in any one of claims 1 to 6.

10. An information data processing terminal, the information data processing terminal being used to implement the three-dimensional information extraction system for a variable speed moving target as claimed in claim 7.

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