A phased array tracking method based on four-dimensional joint weighted dynamic pre-switching

Abstract

The present invention relates to a phased array tracking method based on four-dimensional joint weighted dynamic pre-switching, and belongs to the field of phased array communication technology. The present invention includes: updating the spatiotemporal correlation parameters to the target historical motion trajectory database, generating the target state prediction value based on the UKF prediction method; starting the four-dimensional joint gradual weighting program, performing linear phase interpolation in the time delay dimension, and generating a phase-continuous control signal; solving the mutual coupling matrix, establishing a cross-array phase mapping model based on cubic spline interpolation, and compensating for the residual phase error; dynamically adjusting the number of effective array elements participating in beam synthesis according to the real-time radar scattering cross section, generating the final beam pointing signal, and completing the stable relay tracking of the current cycle. The present invention solves the problems of phase jump and signal attenuation during multi-array switching, and is suitable for continuous tracking of UAVs in high-speed moving scenarios.

Description

Technical Field

[0001] The present invention belongs to the technical field of phased array communications, and in particular relates to a phased array tracking method based on four-dimensional joint weighted dynamic pre-switching, which is suitable for stable relay tracking of vehicle-mounted multi-band phased array antennas. Background Art

[0002] Traditional phased array multi-face switching technologies often use single-dimensional compensation strategies, such as achieving beam transitions only through linear phase interpolation in azimuth or elevation. This approach has the following drawbacks:

[0003] (1) Poor phase continuity: Single-dimensional compensation cannot suppress polarization mismatch and delay jump, resulting in high phase error peaks during array switching and reduced beam pointing accuracy;

[0004] (2) Insufficient dynamic response: The pre-switching algorithm has a large prediction error for nonlinear moving targets, and the switching delay often exceeds 2 beam cycles, resulting in tracking interruption;

[0005] (3) Limited calibration accuracy: compensation relies on the signal from the ground calibration station and is not combined with the synchronous satellite beacon. The root mean square value of the residual phase error is high, which makes it difficult to meet the requirements of high-precision tracking.

[0006] (4) Low energy efficiency: The fixed array element activation ratio strategy wastes significant power in low RCS scenarios;

[0007] In summary, existing technologies have yet to achieve the combined, gradual weighting of the four-dimensional parameters of azimuth, elevation, polarization, and delay, nor do they offer an adaptive coordination mechanism based on target motion characteristics and RCS response. Therefore, a multi-array stabilized tracking solution is urgently needed that can simultaneously address phase jumps, prediction lags, calibration errors, and optimize energy consumption. Summary of the Invention

[0008] In view of this, the present invention provides a phased array tracking method based on four-dimensional joint weighting and dynamic pre-switching. The present invention can achieve stable relay tracking of four phased arrays based on four-dimensional joint weighting and dynamic pre-switching.

[0009] In order to achieve the above object, the technical solution adopted by the present invention is:

[0010] A phased array tracking method based on four-dimensional joint weighted dynamic pre-switching is applied to a UAV phased array system and includes the following steps:

[0011] Step a: Receive the spatiotemporal parameters including the target azimuth through the target trajectory prediction module , pitch angle and speed , update the spatiotemporal correlation parameters to the target historical motion trajectory database, generate the target state prediction value based on the UKF prediction method, and send a trigger signal to the array switching control module;

[0012] Step b: After receiving the trigger signal, the array switching control module starts the four-dimensional joint gradual weighting program, performs linear phase interpolation in the delay dimension, generates a phase-continuous control signal, and sends a mutual coupling compensation request to the phase calibration module;

[0013] Step c: After receiving the mutual coupling compensation request, the phase calibration module solves the mutual coupling matrix, establishes a cross-array phase mapping model based on cubic spline interpolation, compensates the residual phase error to <10°, and sends a phase calibration completion signal to the beamforming module.

[0014] Step d, the beamforming module uses the real-time radar scattering cross section Dynamically adjust the number of effective array elements involved in beamforming , the optimization criterion is to maximize the signal-to-noise ratio ,in is the Boltzmann constant, is the system noise temperature, is the instantaneous signal bandwidth, is the system loss factor; according to the number of effective array elements The final beam pointing signal is generated according to the dynamic adjustment rules and sent to the antenna control unit to complete the stable relay tracking of the current cycle.

[0015] Furthermore, the state equation of the UKF prediction method described in step a is:

[0016] ,

[0017] Among them, the state vector , is the state transition matrix, is zero-mean Gaussian noise, Indicates the change of the corresponding parameter, and the superscript T indicates the transpose of the matrix;

[0018] Process noise covariance matrix of UKF prediction method The update rules are:

[0019] ,

[0020] in, For the forgetting factor; for Momentary state prediction value; represents the discretized time step index, corresponding to the system's duty cycle or sampling moment; Represents the prior state estimate, that is, based on All observation data before and after time Prediction of momentary status.

[0021] Furthermore, the specific method of the four-dimensional joint gradual weighting procedure described in step b is:

[0022] (1) After receiving the trigger signal, the array switching control module obtains the real-time measurement values of the current beam dwell period T and the adjacent array polarization axis offset angle θ, and initializes the time counter t=0; the beam dwell period refers to the duration of the beam staying at a single pointing wave position;

[0023] (2) Based on the real-time measurement of the polarization axis offset angle , construct the rotation matrix of polarization dimension , phase align the polarization directions of adjacent array antenna units;

[0024] (3) In the time interval Internally, synchronously calculate the exit front weight function and the cutting front weight function , where t is the pulse repetition period Increment by integer multiples and reset to zero when t reaches T;

[0025] (4) and The transmission power ratios mapped to the exit and entry planes are respectively, and the constraints are , to achieve continuous transition of radiation energy during the switching process;

[0026] (5) Based on the alignment result of step (2), the two weight functions of step (3), and the transmission power ratio of step (4), the array switching angle is calculated in the spatial dimension:

[0027] ,

[0028] ,

[0029] generating a four-dimensional jointly weighted phase control signal;

[0030] (6) The phase control signal generated in step (5) is sent to the phase calibration module in the form of a mutual coupling compensation request.

[0031] Furthermore, the polarization axis offset angle The measurement method is:

[0032] (1) Generate a polarization phase difference histogram by calibrating the polarization direction signal of the array antenna unit;

[0033] (2) Use the least squares algorithm to fit the histogram peak point, minimize the sum of squares of the residual phase difference through iterative optimization, and solve the angle between the actual polarization axis and the theoretical axis. .

[0034] Furthermore, in step c, the mutual coupling matrix is solved as follows:

[0035] (1) Receiving azimuth , pitch angle The geostationary orbit beacon satellite signal;

[0036] (2) Construct an overdetermined set of equations based on the cross-correlation function of the multi-array received signals:

[0037] ,

[0038] Where x is the mutual coupling parameter vector, obtained by basis function expansion and least squares solution, which is used to compensate for the electromagnetic coupling effect between array elements; b is the observation signal vector, generated by multiple array surfaces receiving geostationary orbit beacon signals, reflecting the coupling between array elements and the difference in propagation paths;

[0039] (3) Calculate the least squares solution using the SVD decomposition method and obtain:

[0040] .

[0041] Furthermore, in step c, a cross-plane phase mapping model is established based on cubic spline interpolation, specifically in the following manner:

[0042] In the adjacent array switching area, a piecewise cubic spline function is used to establish a cross-array phase mapping model. The phase function in each subinterval is expressed as:

[0043]

[0044] in, For the Phase mapping function within the switching interval of each array, in radians; is the spatial angle parameter for array switching, in degrees; For the The starting switching angle of each array surface is measured in real time by the attitude sensor installed on the array surface; are the cubic spline interpolation coefficients.

[0045] Furthermore, the number of effective array elements in step d is The dynamic adjustment rules are:

[0046] (1) When When the noise level is ≥10 dBsm, the lower limit of the ratio of active elements is 30% of the total number of elements.

[0047] (2) When the signal-to-noise ratio (SNR) is less than 10dB, it automatically switches to full array operation mode;

[0048] The adjustment step of the array element activation ratio is 5% of the total number of array elements.

[0049] Furthermore, the method further includes the following steps of phase continuity monitoring:

[0050] (1) Using dual-frequency comparison method, two different wavelengths are emitted simultaneously Detection signal;

[0051] (2) Calculation of equivalent wavelength , amplify the measurement accuracy of phase jump;

[0052] (3) When the differential phase jump exceeds When , the four-dimensional joint gradient weighted procedure is triggered, is the working wavelength.

[0053] The beneficial effects of the present invention are:

[0054] 1. High-precision phase continuity: This invention uses four-dimensional joint gradient weighting (azimuth / elevation / polarization / delay) and a cubic spline phase mapping model to reduce the RMS value of the residual phase error of the array switching, meeting the requirements of high-precision tracking.

[0055] 2. Improved dynamic response speed: The present invention uses the UKF prediction algorithm to predict the switching timing N cycles in advance, which can reduce the tracking interruption time.

[0056] 3. Energy efficiency optimization: The adaptive sub-array reconstruction based on RCS of the present invention can reduce system power consumption while maintaining high communication quality. DETAILED DESCRIPTION

[0057] The technical solutions of the present invention are further described below. Obviously, these contents are only some embodiments of the present invention, not all embodiments. Based on the following embodiments, all other embodiments obtained by persons of ordinary skill in the art without creative work are within the scope of protection of the present invention.

[0058] A phased array tracking method based on four-dimensional joint weighted dynamic pre-switching is applied to the UAV phased array system. During the transition period of switching between adjacent array faces, the exiting array face and the entering array face are synchronously weighted in four dimensions: azimuth, pitch, polarization, and time delay. The transition time is set to beam dwell periods, is a natural number. The method comprises the following steps:

[0059] Step a: Receive the spatiotemporal parameters including the target azimuth through the target trajectory prediction module , pitch angle and speed , the spatiotemporal correlation parameters are updated to the target historical motion trajectory database, the target state prediction value is generated based on the UKF prediction method, and a trigger signal is sent to the array switching control module; wherein, the state equation of the UKF prediction method is:

[0060] ,

[0061] Among them, the state vector , is the state transition matrix, is zero-mean Gaussian noise, Indicates the change of the corresponding parameter, and the superscript T indicates the transpose of the matrix;

[0062] Process noise covariance matrix of UKF prediction method The update rules are:

[0063] ,

[0064] in, is the forgetting factor, which can be 0.95 in this case; for Momentary state prediction value; represents the discretized time step index, corresponding to the system's duty cycle or sampling moment; Represents the prior state estimate, that is, based on All observation data before and after time Prediction of momentary status.

[0065] Step b: After receiving the trigger signal, the array switching control module starts the four-dimensional joint gradual weighting program, performs linear phase interpolation in the delay dimension, generates a phase-continuous control signal, and sends a mutual coupling compensation request to the phase calibration module. The specific method of the four-dimensional joint gradual weighting program is as follows:

[0066] (1) After receiving the trigger signal, the array switching control module obtains the current beam dwell period T and the adjacent array polarization axis offset angle The real-time measurement value of the beam is initialized and the time counter t=0 is initialized; the beam dwell period refers to the duration of the beam staying on a single pointing wave position; the polarization axis offset angle The measurement method is:

[0067] (1.1) Generate a polarization phase difference histogram by calibrating the polarization direction signal of the array antenna unit;

[0068] (1.2) Use the least squares algorithm to fit the histogram peak point, minimize the sum of squares of the residual phase difference through iterative optimization, and solve the angle between the actual polarization axis and the theoretical axis. .

[0069] (2) Based on the real-time measurement of the polarization axis offset angle , construct the rotation matrix of polarization dimension , phase align the polarization directions of adjacent array antenna units;

[0070] In this example, the test frequency band is C band, the target speed is 200m / s, the array configuration is a four-face phased array, each array face has 1024 elements, and the polarization axis offset angle is (measured values), the test results are shown in the following table:

[0071]

[0072] (3) In the time interval Internally, synchronously calculate the exit front weight function and the cutting front weight function , where t is the pulse repetition period Increment by integer multiples and reset to zero when t reaches T;

[0073] (4) and The transmission power ratios mapped to the exit and entry planes are respectively, and the constraints are , to achieve continuous transition of radiation energy during the switching process; specifically:

[0074] Exit array emission power ratio: ,

[0075] Cut-in array transmission power ratio: ,

[0076] in, , The value range is beam dwell period.

[0077] (5) Based on the alignment result of step (2), the two weight functions of step (3), and the transmission power ratio of step (4), the array switching angle is calculated in the spatial dimension:

[0078] ,

[0079] ,

[0080] generating a four-dimensional jointly weighted phase control signal;

[0081] During the phase control process, the rotation matrix of the polarization dimension is:

[0082] ,

[0083] The adjustment step accuracy is 0.1°.

[0084] (6) The phase control signal generated in step (5) is sent to the phase calibration module in the form of a mutual coupling compensation request.

[0085] In step c, after receiving the mutual coupling compensation request, the phase calibration module solves the mutual coupling matrix, establishes a cross-plane phase mapping model based on cubic spline interpolation, compensates the residual phase error to <10°, which includes the mutual coupling phase distortion introduced by the plane switching, and sends a phase calibration completion signal to the beamforming module. The specific method for solving the mutual coupling matrix is as follows:

[0086] (1) Receiving azimuth , pitch angle The geostationary orbit beacon satellite signal;

[0087] (2) Construct an overdetermined set of equations based on the cross-correlation function of the multi-array received signals:

[0088] ,

[0089] Where x is the mutual coupling parameter vector, obtained by basis function expansion and least squares solution, which is used to compensate for the electromagnetic coupling effect between array elements; b is the observation signal vector, generated by multiple array surfaces receiving geostationary orbit beacon signals, reflecting the coupling between array elements and the difference in propagation paths;

[0090] (3) Calculate the least squares solution using the SVD decomposition method and obtain:

[0091] .

[0092] The cross-plane phase mapping model is established based on cubic spline interpolation. The specific method is as follows:

[0093] In the adjacent array switching area, a piecewise cubic spline function is used to establish a cross-array phase mapping model. The phase function in each subinterval is expressed as:

[0094]

[0095] in, For the Phase mapping function within the switching interval of each array, in radians; is the spatial angle parameter for array switching, in degrees; For the The starting switching angle of each array surface is measured in real time by the attitude sensor installed on the array surface; is the cubic spline interpolation coefficient, and its value satisfies the following conditions:

[0096] 1) Phase continuity: ,in, is the measured phase reference value obtained through polarization calibration and mutual coupling compensation at the array switching starting angle;

[0097] 2) First-order derivative is continuous: ;

[0098] 3) Second-order derivative is continuous: .

[0099] Step d, the beamforming module uses the real-time radar scattering cross section Dynamically adjust the number of effective array elements involved in beamforming , the optimization criterion is to maximize the signal-to-noise ratio ,in is the Boltzmann constant, is the system noise temperature, is the instantaneous signal bandwidth, is the system loss factor; according to the number of effective array elements The dynamic adjustment rules of the array generate the final beam pointing signal and send it to the antenna control unit to complete the stable relay tracking of the current cycle; the number of effective array elements is The dynamic adjustment rules are:

[0100] (1) When When the noise level is ≥10 dBsm, the lower limit of the ratio of active elements is 30% of the total number of elements.

[0101] (2) When the signal-to-noise ratio (SNR) is less than 10dB, it automatically switches to full array operation mode;

[0102] The adjustment step of the array element activation ratio is 5% of the total number of array elements.

[0103] In one embodiment, a 5% adjustment step size comparison experiment is performed. =12dBsm, =10ms, the target distance is 50km, and the variable is the adjustment step size (2% / 5% / 10%). The beam pointing error and reconstruction time are evaluated. The experimental results are shown in Table 2 below:

[0104]

[0105] It can be seen that when the step size is greater than 5%, the beam pointing error increases by 1.2dB, and when the step size is less than 5%, the reconstruction time exceeds 30% of.

[0106] Step e: Phase continuity monitoring, specifically:

[0107] (1) Using dual-frequency comparison method, two different wavelengths are emitted simultaneously Detection signal;

[0108] (2) Calculation of equivalent wavelength , amplify the measurement accuracy of phase jump;

[0109] (3) When the differential phase jump exceeds When , the four-dimensional joint gradient weighted procedure is triggered, is the working wavelength.

[0110] The present invention addresses the problems of poor phase continuity, insufficient dynamic response, limited calibration accuracy, and low energy efficiency in conventional phased array systems. By using methods such as four-dimensional joint gradual weighting, a dynamic pre-switching mechanism, cross-array phase calibration technology, and an adaptive sub-array reconstruction strategy, the present invention solves the problems of phase jumps, prediction lag, and energy consumption in multi-array switching. The present invention is suitable for continuous tracking of high-speed moving targets and can be used in vehicle-mounted phased array platforms.

[0111] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. A phased array tracking method based on four-dimensional joint weighted dynamic pre-switching, applied to UAV phased array systems, characterized by: The steps include: Step a: Receive the spatiotemporal parameters including the target azimuth through the target trajectory prediction module , pitch angle and speed , update the spatiotemporal correlation parameters to the target historical motion trajectory database, generate the target state prediction value based on the UKF prediction method, and send a trigger signal to the array switching control module; Step b: After receiving the trigger signal, the array switching control module starts the four-dimensional joint gradual weighting program, performs linear phase interpolation in the delay dimension, generates a phase-continuous control signal, and sends a mutual coupling compensation request to the phase calibration module. The specific method of the four-dimensional joint gradual weighting program is as follows: (1) After receiving the trigger signal, the array switching control module obtains the real-time measurement values of the current beam dwell period T and the adjacent array polarization axis offset angle θ, and initializes the time counter t=0; the beam dwell period refers to the duration of the beam staying at a single pointing wave position; (2) Based on the real-time measurement of the polarization axis offset angle , construct the rotation matrix of polarization dimension , phase align the polarization directions of adjacent array antenna units; (3) In the time interval Internally, synchronously calculate the exit front weight function and the cutting front weight function , where t is the pulse repetition period Increment by integer multiples and reset to zero when t reaches T; (4) and The transmission power ratios mapped to the exit and entry planes are respectively, and the constraints are , to achieve continuous transition of radiation energy during the switching process; (5) Based on the alignment result of step (2), the two weight functions of step (3), and the transmission power ratio of step (4), the array switching angle is calculated in the spatial dimension: ， ， generating a four-dimensional jointly weighted phase control signal; (6) sending the phase control signal generated in step (5) to the phase calibration module in the form of a mutual coupling compensation request; Step c: After receiving the mutual coupling compensation request, the phase calibration module solves the mutual coupling matrix, establishes a cross-array phase mapping model based on cubic spline interpolation, compensates the residual phase error to <10°, and sends a phase calibration completion signal to the beamforming module. Step d, the beamforming module uses the real-time radar scattering cross section Dynamically adjust the number of effective array elements involved in beamforming , the optimization criterion is to maximize the signal-to-noise ratio ,in is the Boltzmann constant, is the system noise temperature, is the instantaneous signal bandwidth, is the system loss factor; according to the number of effective array elements The final beam pointing signal is generated according to the dynamic adjustment rules and sent to the antenna control unit to complete the stable relay tracking of the current cycle.

2. The phased array tracking method based on four-dimensional joint weighted dynamic pre-switching according to claim 1, characterized in that: The equation of state for the UKF prediction method described in step a is: ， Among them, the state vector , is the state transition matrix, is zero-mean Gaussian noise, Indicates the change of the corresponding parameter, and the superscript T indicates the transpose of the matrix; Process noise covariance matrix of UKF prediction method The update rules are: ， in, For the forgetting factor; for Momentary state prediction value; represents the discretized time step index, corresponding to the system's duty cycle or sampling moment; Represents the prior state estimate, that is, based on All observation data before and after time Prediction of momentary status.

3. The phased array tracking method based on four-dimensional joint weighted dynamic pre-switching according to claim 1, characterized in that: The polarization axis offset angle The measurement method is: (1) Generate a polarization phase difference histogram by calibrating the polarization direction signal of the array antenna unit; (2) Use the least squares algorithm to fit the histogram peak point, minimize the sum of squares of the residual phase difference through iterative optimization, and solve the angle between the actual polarization axis and the theoretical axis. .

4. The phased array tracking method based on four-dimensional joint weighted dynamic pre-switching according to claim 1, characterized in that: In step c, the mutual coupling matrix is solved as follows: (1) Receiving azimuth , pitch angle The geostationary orbit beacon satellite signal; (2) Construct an overdetermined set of equations based on the cross-correlation function of the multi-array received signals: ， Where x is the mutual coupling parameter vector, obtained by basis function expansion and least squares solution, which is used to compensate for the electromagnetic coupling effect between array elements; b is the observation signal vector, generated by multiple array surfaces receiving geostationary orbit beacon signals, reflecting the coupling between array elements and the difference in propagation paths; (3) Calculate the least squares solution using the SVD decomposition method and obtain: 。 5. The phased array tracking method based on four-dimensional joint weighted dynamic pre-switching according to claim 4, characterized in that: In step c, a cross-plane phase mapping model is established based on cubic spline interpolation. The specific method is as follows: In the adjacent array switching area, a piecewise cubic spline function is used to establish a cross-array phase mapping model. The phase function in each subinterval is expressed as: in, For the Phase mapping function within the switching interval of each array, in radians; is the spatial angle parameter for array switching, in degrees; For the The starting switching angle of each array surface is measured in real time by the attitude sensor installed on the array surface; are the cubic spline interpolation coefficients.

6. The phased array tracking method based on four-dimensional joint weighted dynamic pre-switching according to claim 1, characterized in that: The number of effective array elements in step d The dynamic adjustment rules are: (1) When When the noise level is ≥10 dBsm, the lower limit of the ratio of active elements is 30% of the total number of elements. (2) When the signal-to-noise ratio (SNR) is less than 10dB, it automatically switches to full array operation mode; The adjustment step of the array element activation ratio is 5% of the total number of array elements.

7. The phased array tracking method based on four-dimensional joint weighted dynamic pre-switching according to claim 1, characterized in that: Also included are the steps for phase continuity monitoring: (1) Using dual-frequency comparison method, two different wavelengths are emitted simultaneously Detection signal; (2) Calculation of equivalent wavelength , amplify the measurement accuracy of phase jump; (3) When the differential phase jump exceeds When , the four-dimensional joint gradient weighted procedure is triggered, is the working wavelength.

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