Four-plane phased array system based on multi-array-plane dynamic signal synthesis

Abstract

The invention provides a four-plane phased array system based on multi-array-plane dynamic signal synthesis, and belongs to the technical field of wireless communication. The system comprises four symmetrically distributed array planes, each array plane is provided with an independent signal processing module, and the system also comprises a dynamic overlapping region signal synthesis module, a self-adaptive array element activation module, a closed-loop phase correction module and a central synthesis control module. According to the invention, the dynamic signal synthesis of the multi-array-plane overlapping region can be realized, the phase error is reduced, the multi-path interference and nonlinear distortion can be synchronously inhibited, and the array element activation strategy is optimized to improve the response speed and gain stability of the scanning boundary region.

Description

Technical Field

[0001] The present invention belongs to the field of wireless communication technology, and particularly relates to a four-sided phased array system based on multi-array dynamic signal synthesis, which can be used for unmanned aerial vehicle and satellite communication, and is particularly suitable for signal synthesis and synchronization calibration in multi-target tracking, wide-angle scanning and high-dynamic environments. Background Art

[0002] The traditional phased array system has the following problems in wide-angle scanning:

[0003] (1) Signal interference between arrays: Adjacent arrays have inconsistent phases and gain fluctuations due to signal overlap in the scanning boundary region (such as ±45°).

[0004] (2) Low calibration efficiency: The centralized calibration architecture is difficult to compensate for multipath interference and amplifier nonlinear distortion in real time.

[0005] (3) Insufficient dynamic response: The existing array element activation strategy cannot be dynamically adjusted according to the scanning angle, resulting in a delay in beam pointing switching.

[0006] In the prior art, generally, the scanning gain loss is compensated by a fixed overlapping region, but the problem of dynamic weight optimization is not solved; the existing sub-array element group design does not involve a multi-array collaborative calibration method. Therefore, there is an urgent need for a system that integrates dynamic signal synthesis, real-time calibration, and adaptive array element switching. Summary of the Invention

[0007] In view of this, the present invention provides a four-sided phased array system based on multi-array dynamic signal synthesis. The present invention can realize the dynamic signal synthesis of the multi-array overlapping region, reduce the phase error, can synchronously suppress multipath interference and nonlinear distortion, and optimize the array element activation strategy to improve the response speed and gain stability of the scanning boundary region.

[0008] In order to achieve the above object, the technical solution adopted by the present invention is:

[0009] A four-sided phased array system based on multi-array dynamic signal synthesis, including four symmetrically distributed arrays, each array is configured with an independent signal processing module, and further includes a dynamic overlapping region signal synthesis module, an adaptive array element activation module, a closed-loop phase correction module, and a central synthesis control module;

[0010] The working process of the system is as follows:

[0011] (a) The central synthesis control module generates a scanning strategy instruction according to the combat mission, and sends beam pointing parameters and scanning period configuration information to each signal processing module;

[0012] After receiving the instruction, the signal processing module performs adaptive Kalman noise reduction processing on the original received signal, and after completing the time delay compensation, it sends the preprocessed signal to the adaptive array element activation module;

[0013] Based on the Kalman filter target beam pointing prediction model, the adaptive array element activation module calculates the optimal array element combination in the overlapping area of adjacent array surfaces, and dynamically activates the cross-polarized array elements in the 50% overlapping area of adjacent array surfaces through the switch matrix. The activation state parameters are fed back to the dynamic overlapping area signal synthesis module in real time;

[0014] The dynamic overlapping area signal synthesis module receives the preprocessed signals of each array surface, iteratively solves the optimal weights in the parallel computing unit, completes the weighted synthesis operation within the ±45° scanning range, and outputs the synthesized equivalent signal to the central synthesis control module;

[0015] The closed-loop phase correction module synchronously monitors the phase consistency of the synthesized signal, corrects the amplifier distortion in real time through the nonlinear phase compensation unit, and feeds back the updated calibration parameters to the signal processing modules of each array surface;

[0016] The central synthesis control module synthesizes the synthesized signals of each array surface, completes the multi-target detection and tracking decision, generates a scan cycle completion report, and initiates a new scan cycle according to the tactical requirements.

[0017] Furthermore, the four symmetrically distributed array surfaces satisfy all of the following conditions:

[0018] (1) The element spacing is less than or equal to half a wavelength;

[0019] (2) There is a 20%-30% overlapping coverage rate between adjacent array surfaces. The array elements in the overlapping area are arranged staggeredly, and the polarization directions of adjacent array elements are orthogonal; among them, the overlapping coverage rate refers to the proportion of the number of activated array elements in adjacent array surfaces to the total number of array elements in a single array surface.

[0020] Furthermore, the specific method for the adaptive array element activation module to dynamically activate the cross-polarized array elements in the 50% overlapping area of adjacent array surfaces through the switch matrix is as follows: dynamically switch the connection between the array elements and the T / R components through the PIN diode switch matrix, and the activation conditions are one of the following:

[0021] (1) The polarization direction of the array element matches the polarization of the target signal;

[0022] (2) The element spacing ≤ half a wavelength;

[0023] (3) The real-time signal-to-noise ratio threshold meets the preset conditions;

[0024] Among them, the PIN diode switch matrix is composed of multiple PIN diodes, and each PIN diode is connected in parallel with an RC absorption circuit and is controlled to be turned on and off by a gate drive voltage.

[0025] Furthermore, the dynamic overlapping area signal synthesis module includes:

[0026] A phase calibration unit that measures the initial phase difference between arrays based on the cross-correlation method and compensates for channel inconsistency through a PID feedback loop;

[0027] A synthesis operation unit that outputs a synthesized signal according to the following formula:

[0028]

[0029] where is the equivalent signal after synthesis; is the dynamic weight of the i-th array signal; is the number of adjacent arrays participating in the synthesis; is the original received signal of the i-th array; is the phase rotation of the imaginary signal; is the initial phase offset of the i-th array signal; is the phase synchronization error calibration value between multiple arrays;

[0030] The dynamic overlapping area signal synthesis module dynamically adjusts the dynamic weights of the signals of each array by real-time monitoring of the element activation status in the overlapping area of adjacent arrays and combining with the target beam pointing prediction model ; when the scanning angle changes, the dynamic overlapping area signal synthesis module, according to the number of adjacent arrays participating in the synthesis and the phase synchronization error calibration value between multiple arrays, iteratively optimizes through a parallel computing unit to ensure the phase consistency of the synthesized signal within the scanning range of ±45°.

[0031] Furthermore, the closed-loop phase correction module measures the initial phase difference between arrays of the synthesized signal by the cross-correlation method. For the high-order phase error introduced by amplifier distortion, a pre-distortion compensation algorithm is used to generate and distributes in real time to the signal processing modules of each array through a high-speed serial bus.

[0032] Furthermore, the specific method for dynamically adjusting the dynamic weights of the signals of each array is as follows:

[0033] (1) Construct an objective function based on the signal-to-noise ratio maximization criterion;

[0034] (2) Iteratively solve the optimal solution through subspace matching pursuit and least squares method. The subspace matching pursuit is implemented based on a pre-constructed sparse basis vector library.

[0035] The beneficial effects of the present invention are as follows:

[0036] 1. Expand the scanning range: The present invention improves the scanning angle through the collaborative coverage of four arrays.

[0037] 2. Improve the accuracy: The present invention can reduce the phase synchronization error and improve the beam pointing accuracy.

[0038] 3. Strengthen the anti-interference ability: The present invention adopts a closed-loop calibration architecture to improve the multipath interference suppression ratio.

[0039] 4. Optimize the dynamic response: The present invention reduces the element switching delay through the PIN diode switch matrix, making it more suitable for high-mobility UAV communication scenarios. Description of the Drawings

[0040] Figure 1 It is a schematic diagram of the system composition in the embodiment of the present invention. Specific Embodiments

[0041] Next, the technical solutions of the present invention will be further described in conjunction with the drawings. Obviously, these are only part of the embodiments of the present invention, rather than all embodiments. Based on the following embodiments, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the protection scope of the present invention.

[0042] A four-phase phased array system based on multi-array dynamic signal synthesis, as Figure 1 shown, the system includes:

[0043] (a) Four symmetrically distributed arrays, each array contains a dynamically activatable sub-element group, and each array is configured with an independent signal processing module;

[0044] (b) A dynamic overlapping area signal synthesis module for weighted synthesis of signals in the ±45° scanning range of adjacent arrays;

[0045] (c) An adaptive element activation module that predicts the scanning angle according to the target beam pointing and dynamically controls the element activation state in the overlapping area of adjacent arrays;

[0046] (d) A closed-loop phase correction module that adjusts the weight and phase offset based on the error signal to suppress multipath interference, suppresses the phase distortion introduced by amplifier non-linearity through a non-linear phase compensation unit, dynamically matches the calibration period with the beam scanning rate, and updates the error compensation;

[0047] (e) A central synthesis control module, which is used to initiate and control the multi-target detection and tracking decision-making process and generate a scan cycle completion report;

[0048] (f) A centralized frequency source, which provides a reference clock signal to each array face.

[0049] Among them, the four array faces are arranged in a square symmetric layout, and the sub-array element groups of each array face meet the following conditions:

[0050] (1) The element spacing is less than or equal to half a wavelength;

[0051] (2) There is an overlapping coverage rate of 20%-30% between adjacent array faces. The array elements in the overlapping area are arranged staggeredly, and the polarization directions of adjacent elements are orthogonal. The overlapping coverage rate refers to the proportion of the number of active elements in the adjacent array faces to the total number of elements in a single array face. For example, if a single array face contains 100 elements, then 20-30 elements need to be activated in the overlapping area.

[0052] In this example, all four array faces use microstrip patch antennas. The element spacing is half a wavelength, and the overlapping coverage rate of the adjacent array faces is 25%. The array elements in the overlapping area are arranged staggeredly, and the polarization directions are orthogonal (alternating horizontal and vertical polarizations). They are integrated through the LTCC (Low Temperature Co-fired Ceramic) process to reduce the mutual coupling effect to below -30 dB.

[0053] The dynamic overlapping area signal synthesis module includes:

[0054] (1) A phase calibration unit, which measures the initial phase difference between array faces based on the cross-correlation method and compensates for channel inconsistency through a PID feedback loop;

[0055] (2) A synthesis operation unit, which outputs a synthesized signal according to the following formula:

[0056]

[0057] Among them, is the synthesized equivalent signal; is the dynamic weight of the signal of the i-th array face; is the number of adjacent array faces participating in the synthesis; is the original received signal of the i-th array face; is the phase rotation of the imaginary signal; is the initial phase offset of the signal of the i-th array face; is the phase synchronization error calibration between multiple array faces.

[0058] The dynamic overlapping region signal synthesis module dynamically adjusts the parameters in the weighted synthesis algorithm by monitoring the activation status of the elements in the overlapping region of adjacent arrays (coverage rate of 20%-30%) in real time and combining the target beam pointing prediction model. When the scanning angle changes, the module, according to and , iteratively optimizes through the FPGA parallel computing unit to ensure the phase consistency of the synthesized signals within the scanning range of ±45°.

[0059] In this example, the phase calibration unit uses a Xilinx UltraScale+ FPGA to implement the cross-correlation method for measurement, with a sampling frequency of 100 MHz, a feedback loop bandwidth ≥10 kHz, and a compensation for channel inconsistency error Δϕ = 3°.

[0060] Dynamic weights are dynamically adjusted through an improved SUMPLE algorithm. The improved SUMPLE algorithm runs in the FPGA parallel computing unit, and the specific method is as follows:

[0061] (1) Construct an objective function based on the maximum signal-to-noise ratio criterion;

[0062] In this example, the sparse basis vector library is constructed based on the K-SVD algorithm, and the weight iteration convergence time ≤1 ms; 256 groups of sparse basis vector libraries are constructed within the FPGA, and each group contains pre-computed beam weight combinations.

[0063] (2) Iteratively solve the optimal weights through subspace matching pursuit and the least squares method. The subspace matching pursuit is implemented based on a pre-constructed sparse basis vector library, and the least squares iteration optimizes the complex weights through the CORDIC core. The iteration formula is , where is the step size, is the signal covariance matrix, is the gradient vector.

[0064] The adaptive element activation module performs the following operations:

[0065] (1) Dynamically activate the elements in the overlapping region of adjacent arrays according to the predicted scanning angle of the target beam pointing;

[0066] (2) When the scanning angle approaches the junction of the arrays, only activate 50% of the overlapping region elements of the two adjacent arrays to compensate for the gain loss through synthesis;

[0067] (3) Dynamically switch the connection relationship between the array elements and the T / R components through a switch matrix. The switch matrix uses a PIN diode array with a switching delay < 10 ns. The switch matrix uses a GaAs PIN diode array (reverse recovery time < 2 ns), and the measured switching delay is 8.5 ns. The dynamic activation strategy is based on Kalman filter prediction, and the beam pointing error ≤ 0.3°.

[0068] The adaptive array element activation module is based on the Kalman filter target beam pointing prediction model to calculate the optimal array element combination in the overlapping area of adjacent array surfaces. Dynamically switch the connection between the array elements and the T / R components through a PIN diode switch matrix (switching delay < 10 ns). The activation conditions include:

[0069] (1) The polarization direction of the array element matches the polarization of the target signal;

[0070] (2) The array element spacing ≤ half wavelength;

[0071] (3) The real-time signal-to-noise ratio threshold meets the preset conditions.

[0072] The PIN diode switch matrix is composed of multiple PIN diodes (such as the MA4P124 series). Each diode is connected in parallel with an RC absorption circuit (R = 50 Ω, C = 1 pF), and the on / off is controlled by the gate drive voltage (typical value +5V / -3V). The switching delay is jointly determined by the carrier transit time (< 5 ns) and the drive circuit response time (< 5 ns).

[0073] The closed-loop phase correction module measures the initial phase difference between array surfaces of the synthesized signal through the cross-correlation method. For the high-order phase error introduced by amplifier distortion, a pre-distortion compensation algorithm is used to generate , and the calibration parameters are distributed to each array surface signal processing module in real time through a high-speed serial bus, and the update period ≤ 1 μs.

[0074] The present invention can be used in vehicle-mounted phased array platforms, can realize dynamic signal synthesis in the overlapping area of multiple array surfaces, reduce phase errors, can synchronously suppress multipath interference and nonlinear distortion, and optimize the array element activation strategy to improve the response speed and gain stability in the scanning boundary area. Specifically, the present invention dynamically weights and synthesizes the signals within the scanning range of adjacent array surfaces, and combines the improved SUMPLE algorithm to optimize the weight allocation to achieve high-precision beamforming. The present invention adopts a hierarchical synchronous calibration architecture, suppresses multipath interference through centralized clock synchronization and closed-loop phase correction, and at the same time uses an adaptive array element activation strategy to optimize the gain compensation in the scanning boundary area.

[0075] In summary, the technical solution of the present invention significantly improves the coverage, signal stability, and anti-interference ability of multi-array collaborative scanning, solves the problems of signal interference between arrays, low calibration efficiency, and insufficient dynamic response in conventional phased array systems, and is applicable to the fields of UAV communication, radar detection, and satellite communication.

[0076] As described above, the above are only specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention can easily think of changes or substitutions, which should be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. A four-sided phased array system based on multi-plane dynamic signal synthesis, characterized in that: It includes four symmetrically distributed array planes, each of which is equipped with an independent signal processing module, and also includes a dynamic overlapping area signal synthesis module, an adaptive array element activation module, a closed-loop phase correction module and a central synthesis control module; The system works as follows: (a) The central synthesis control module generates scanning strategy instructions according to the combat mission and sends beam pointing parameters and scanning cycle configuration information to each signal processing module; (b) After receiving the instruction, the signal processing module performs adaptive Kalman noise reduction processing on the original received signal, and sends a pre-processing completion signal to the adaptive array element activation module after completing the delay compensation; (c) The adaptive array element activation module calculates the optimal array element combination in the overlapping area of ​​adjacent array planes based on the Kalman filter target beam pointing prediction model, and dynamically activates the staggered polarization array elements in the 50% overlapping area of ​​adjacent array planes through the switch matrix. The activation state parameters are fed back to the dynamic overlapping area signal synthesis module in real time. (d) The dynamic overlapping area signal synthesis module receives the pre-processed signals of each array surface, iteratively solves the optimal weight in the parallel computing unit, completes the weighted synthesis operation within the ±45° scanning range, and outputs the synthesized equivalent signal to the central synthesis control module; (e) The closed-loop phase correction module synchronously monitors the phase consistency of the synthesized signal, performs real-time correction of the amplifier distortion through the nonlinear phase compensation unit, and feeds back the updated calibration parameters to the signal processing modules of each array plane; (f) The central synthesis control module integrates the synthetic signals of each array surface, completes multi-target detection and tracking judgment, generates a scan cycle completion report, and initiates a new round of scan cycle according to tactical requirements.

2. The four-surface phased array system based on multi-surface dynamic signal synthesis according to claim 1, characterized in that: The four symmetrically distributed fronts satisfy all the following conditions: (1) The array element spacing is less than or equal to half the wavelength; (2) There is an overlap coverage ratio of 20%-30% between adjacent array planes. The array elements in the overlapping area are arranged in a staggered manner, and the polarization directions of adjacent array elements are orthogonal. The overlap coverage ratio refers to the ratio of the number of activated array elements in adjacent array planes to the total number of array elements in a single array plane.

3. The four-surface phased array system based on multi-surface dynamic signal synthesis according to claim 1, characterized in that: The adaptive array element activation module dynamically activates the interlaced polarization array elements in the 50% overlap area of ​​adjacent array planes through the switch matrix. The specific method is: dynamically switch the connection between the array element and the T / R component through the PIN diode switch matrix. The activation condition is one of the following: (1) The polarization direction of the array element matches the polarization of the target signal; (2) Array element spacing ≤ half wavelength; (3) The real-time signal-to-noise ratio threshold meets the preset conditions; The PIN diode switch matrix is ​​composed of a plurality of PIN diodes, each PIN diode is connected in parallel with an RC absorption circuit, and the on-off is controlled by a gate drive voltage.

4. The four-surface phased array system based on multi-surface dynamic signal synthesis according to claim 1, characterized in that: The dynamic overlapping area signal synthesis module comprises: Phase calibration unit, which measures the initial phase difference between arrays based on the cross-correlation method and compensates for channel inconsistency through a PID feedback loop; The synthesis operation unit outputs the synthesis signal according to the following formula: ； in, is the equivalent signal after synthesis; is the dynamic weight of the i-th array signal; is the number of adjacent arrays involved in the synthesis; is the original received signal of the i-th array; is the phase rotation of the imaginary signal; is the initial phase offset of the i-th array signal; is the phase synchronization error calibration value among multiple arrays; The dynamic overlap area signal synthesis module monitors the activation status of the array elements in the overlapping area of ​​adjacent arrays in real time, combines the target beam pointing prediction model, and dynamically adjusts the dynamic weights of each array signal. ; When the scanning angle changes, the dynamic overlapping area signal synthesis module is based on the number of adjacent arrays involved in the synthesis Phase synchronization error calibration value between multiple arrays , iteratively optimized through parallel computing units , ensuring the phase consistency of the synthetic signal within the ±45° scanning range.

5. The four-surface phased array system based on multi-surface dynamic signal synthesis according to claim 4, characterized in that: The closed-loop phase correction module measures the initial phase difference between the array planes of the synthetic signal by the cross-correlation method, and uses the pre-distortion compensation algorithm to generate the high-order phase error introduced by the amplifier distortion. and connects the The signal processing modules are distributed to each array in real time.

6. The four-surface phased array system based on multi-surface dynamic signal synthesis according to claim 4, characterized in that: Dynamically adjust the dynamic weight of each array signal The specific method is: (1) Constructing the objective function based on the signal-to-noise ratio maximization criterion; (2) Solve the optimal solution through subspace matching pursuit and least squares method iteration , the subspace matching pursuit is implemented based on a pre-built sparse basis vector library.

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