Online joint calibration method, device and system for multi-source errors of active phased array antenna

Abstract

The application discloses a kind of active phased array antenna multi-source error online joint calibration method, device and system, belong to antenna technical field.The method includes: determining antenna structure parameter;Three calibration paths are executed, respectively for collecting array element channel signal to estimate IQ imbalance error and equivalent channel error matrix, collecting displacement information to reconstruct array surface displacement field and calculate spatial phase error, collect temperature information to interpolate temperature field and calculate array element excitation amplitude and phase error;After time synchronization and coordinate registration of error term obtained by three paths, electromechanical thermal coupling model under multi-source error is established, the electrical performance under antenna service condition is calculated, and then the theoretical compensation amount is obtained, and the quantization error of phase shifter / attenuator is considered, and the actual excitation current amplitude and phase compensation amount is output.The method realizes the online joint calibration of the electrical performance of active phased array antenna under service condition by parallel processing multi-source error, and can improve the environmental adaptability and pointing accuracy of antenna.

Description

Technical Field

[0001] This invention belongs to the field of antenna technology, specifically relating to an online joint calibration method, device, and system for multi-source errors of active phased array antennas. Background Technology

[0002] As radar detection and wireless communication technologies evolve towards higher frequencies, ultra-large-scale arrays, and higher power densities, phased array antennas have become core payloads in spaceborne systems, 5G / 6G base stations, and high-performance weaponry. However, these antennas face extreme force and heat environments during actual service. High-density integration leads to thermal accumulation on the array surface, causing drift in the dielectric parameters of the material. The combined effect of external loads and thermal expansion induces nonlinear deformation of the array structure, resulting in element position shifts and pointing errors. Existing calibration techniques mostly employ static or single-physics-field models, i.e., correcting thermal drift or mutual coupling errors in isolation. This method ignores the deep dynamic interaction mechanisms between various physical factors: structural deformation directly changes the physical spacing between array elements, thus significantly altering near-field electromagnetic mutual coupling characteristics; and the mismatch in mutual coupling impedance, in turn, affects the power consumption and heat distribution of the active channel, forming a complex "structure-thermal-electromagnetic" strongly coupled closed loop.

[0003] To analyze the coupling problem between the hardware non-idealities of phased array antennas and complex environments, Y. Ginzberg, S. Efimov and E. Cohen. Robust mmWave Beamforming via Integration of Digital IQImbalance Compensation and Sparse-Grid-Based Gain / Phase Calibration[C]. IEEE Transactions on Antennas and Propagation, vol. 74, no. 1, pp. 51-62, Jan.2026, doi: 10.1109 / TAP.2025.3620033. This paper proposes a cascaded all-digital calibration scheme for millimeter-wave phased array receivers to effectively compensate for complex environmental coupling effects. However, antenna arrays are not mechanically rigid systems with constant thermal environments. Structural deformation and thermal gradients generated under actual environmental loads can lead to dynamic performance degradation. Therefore, it is necessary to consider the multi-physics field strong coupling mechanism between physical geometric deformation, material property drift caused by thermal accumulation and electromagnetic mutual coupling, namely the "structure-thermal-electromagnetic" closed-loop interaction, so that the compensation system can adapt to real-time changes under extreme conditions. Furthermore, regarding the degradation of the electrical performance of active phased array antennas due to temperature loads on antenna RF devices, Zhong L, Fu G, Lu JA research for influence of temperature on T / R module in radar[C], IEEE Prognostics and System Health Management Conference, Beijing, China, Oct. 21-23, 2015: 1-9 investigated the mechanism by which the performance of T / R components and their core solid-state microwave power devices is affected by temperature changes. A simplified circuit model of the T / R components was built, and the circuit performance changes with temperature were given. However, phased array antennas under environmental loads not only experience performance degradation at the circuit and device physical level, but also require simultaneous analysis of nonlinear deformation of the array structure caused by thermal loads and the dynamic interaction between structural deformation and electromagnetic mutual coupling effects. Current active phased array antenna compensation methods typically analyze and calibrate the structural, electromagnetic, and thermal aspects separately, making it difficult to construct a multi-physics field cooperative coupling model that includes a closed loop of "structural deformation-thermal distribution-electromagnetic mutual coupling" to evaluate its comprehensive impact on phased array antenna system-level indicators, such as beam pointing and sidelobe level.

[0004] In summary, there is currently a lack of methods for simultaneously analyzing the sources of various errors and performing online joint calibration for active phased array antennas in service. Summary of the Invention

[0005] To address the aforementioned problems in the existing technology, this invention provides an online joint calibration method, device, and system for multi-source errors of active phased array antennas. By arranging temperature and displacement sensors on the phased array antenna surface, the antenna temperature and strain information under service conditions are collected in real time. An electrical performance calculation model is established, including the antenna equivalent channel error matrix, element position offset, and element feeding error. Considering the quantization errors of commonly used digital phase shifters and attenuators in engineering, the actual adjustment amounts of the element excitation current amplitude and phase are given, ensuring the reliable electrical performance of the active phased array antenna under operating conditions.

[0006] The technical problem to be solved by this invention is achieved through the following technical solution: This invention provides an online joint calibration method for multi-source errors in active phased array antennas. This method executes three calibration paths to handle channel errors, structural displacement errors, and temperature-fed errors respectively, ultimately fusing them to obtain a comprehensive compensation amount. Specifically, it includes the following steps: (1) Obtain the structural parameters and material properties of the active phased array antenna; (2) Execute the following three calibration paths: Calibration Path A: Acquire array element channel signals; estimate the IQ imbalance gain / phase error of each channel using the signal blind compensation algorithm; estimate the equivalent channel error matrix using the GPC calibration algorithm; Calibration Path B: Collect antenna array displacement information, reconstruct the array displacement field based on finite element shape functions; extract the position error of antenna elements, and calculate the spatial phase error of the array antenna based on the position error of the elements; Calibration Path C: Collect antenna array surface temperature information, interpolate the array surface temperature field, determine the temperature field distribution of the feed system; extract the T / R component temperature values ​​corresponding to the array elements, and calculate the array element excitation amplitude and phase error based on the device temperature drift performance; (3) Perform time synchronization and coordinate registration on the error terms obtained in step (2); (4) Establish an electromechanical-thermal coupling model under multi-source error and calculate the electrical performance of the phased array antenna under service conditions; (5) Calculate the amplitude error and phase error of the equivalent excitation of each array element relative to the nominal excitation; (6) Calculate the theoretical array element current amplitude / phase compensation amount; (7) Considering the quantization error of the phase shifter / attenuator, the actual excitation current amplitude and phase compensation amount after quantization is obtained.

[0007] Furthermore, in step (1), the structural parameters of the active phased array antenna include the number of antenna elements, spacing, distribution of the feed system, and coordinates of the temperature sensor; the material properties include the specific heat capacity of the material. thermal conductivity and density .

[0008] Further, in step (2), the calibration path A involves acquiring array element channel signals, specifically including: The original signal is down-converted to a 1GHz intermediate frequency signal using a local oscillator circuit. A high-speed AD converter is used to acquire each signal and transmit it to the FPGA module. Then, the signal is down-converted to baseband in the FPGA. After preliminary filtering, the processed baseband I / Q data is transmitted to the host computer.

[0009] Further, in step (2), calibration path A, the IQ imbalance gain / phase error of each channel is estimated according to the signal blind compensation algorithm, specifically including: According to the processed number Baseband sampling signal with IQ imbalance and image interference acquired by the path , ,in, Total number of channels This represents the nth data point in the digital signal stream; first, construct a string of length... FIR filter The output of the filter is calculated using the following formula: (1), Then on The statistical properties were examined, and the following adaptive formula was used to... Update: (2), In the formula, Step size, After the algorithm converges, the FIR filter automatically learns the inverse function of the hardware error, and the output... This eliminates the I / Q imbalance.

[0010] Further, in step (2), calibration path A, estimating the equivalent channel error matrix according to the GPC calibration algorithm specifically includes: (a) Place a transmitter in the far field of the phased array antenna to transmit a continuous wave (CW), and select a set of sparse angles. I / Q imbalance compensation is performed on the signal received by the phased array antenna at each angle to ensure data purity; (b) The acquired time-domain signal , Perform a discrete Fourier transform to obtain the frequency domain signal. , It is a complex array of length N, where each element represents a specific frequency component; the phase value of the signal is extracted at the CW frequency point using the following formula: (3), The total phase calculated by formula (3) consists of two parts: the geometric phase determined by the antenna position and the total phase calculated by formula (3). Phase error, including element mutual coupling and environmental coupling. in For the spacing between array elements, For wavelength, The calculation formula is as follows: (4); (c) Calculate the time-domain sequence of the signal The root mean square value, after normalization, yields the amplitude gain deviation of each channel relative to the reference: (5); (d) Using spline interpolation algorithm to obtain the gain error curve of sparse mesh and phase error curve A smooth fit is performed to generate error data for a high-density network, and finally the obtained error is encapsulated into a matrix. The specific form is as follows: (6).

[0011] Furthermore, in step (2), the calibration path B, reconstructing the antenna array displacement field specifically includes: (a) Assuming the antenna array is discretized into several elements, for a certain element Let the coordinates of any point within the unit be... The displacement vector at that point is According to finite element theory, displacements within an element can be represented by nodal displacement vectors. And shape function matrix To indicate: (7), Because the raw data measured by the sensor is strain It is the derivative function of the displacement, and the differential operator is denoted as . : (8), Substituting equation (7) into equation (8) yields: (9), Define the strain matrix Then we have: (10); (b) According to the first The coordinates are The strain value measured on the sensor , ,in Given the total number of displacement sensors, for each measuring point, the following can be listed: (11), Wherein, global node displacement vector For local units Mapping; All Solving the simultaneous equations of the sensors, we obtain a matrix form: (12), in, It is a column vector of all sensor data; It is a column vector containing the unknown degrees of freedom of all nodes; It is a transformation matrix, derived from the strain matrix of each measurement point. Assembled; Since strain is the derivative of displacement, pure strain data cannot determine the displacement of a rigid body. Therefore, boundary conditions must be introduced, assuming a sufficiently large number of sensors are deployed. Greater than the number of degrees of freedom of the unknown nodes In this case, the least squares method is used to solve the problem. (13), Find the nodal displacements Then, the displacement at any position on the plane can be calculated according to formula (7); In step (2), in calibration path B, for a linear array, the relative position error at the array element is calculated based on calibration path B. The spatial phase error of the array antenna is calculated as follows: (14), in, The free space wave constant, The wavelength of electromagnetic waves, This represents the positional error of the array elements. The unit vector in the direction of the far-field observation point. These are the unit vectors on the two coordinate axes, respectively. This refers to the pitch angle.

[0012] Furthermore, in the calibration path C of step (2), the first step is based on the antenna array arrangement. Temperature information collected by a temperature sensor is set as follows: , ,in, Given the total number of temperature sensors, the temperature field of the radome structure is interpolated using the following interpolation function: (15) (16), in, and The first The temperature sensor and the first The position coordinates of the location that needs to be interpolated; For the first Temperature values ​​measured at each location For the antenna array... Temperature at each location Weighting factors; To prevent the setting of tiny non-zero values ​​when the measurement point and interpolation point are the same, To control the factors that influence the weights based on distance, To control the weighting factor Factors; Furthermore, in step (2), the specific method for calculating the amplitude and phase error of the array element excitation based on the device temperature drift performance in calibration path C is as follows: Based on the effect of temperature on the excitation current amplitude, the normalized excitation amplitude error is calculated using the following formula: (17), In the formula, For array surface temperature, To normalize the excitation amplitude error, the amplitude error of the excitation current can be expressed as: ,in This represents the maximum value of the excitation current amplitude; Based on the effect of temperature on the phase of the excitation current, the phase error is calculated using the following formula. for: (18).

[0013] Furthermore, step (4) specifically includes: Ideally, the radiation pattern function of a linear array antenna at a distant observation point is: (19), in, This is the deflection angle; The initial excitation current amplitude of the array element. The initial excitation current phase of the array element. The wave constant; The radiation pattern function of the radiating element; Based on the equivalent channel error matrix obtained from calibration path A, the spatial phase error obtained from calibration path B, and the element excitation amplitude and phase error obtained from calibration path C, the radiation pattern function of the far-field observation point of the linear array antenna in actual operation can be established: (20), By comparing the radiation pattern function, the amplitude change rate and phase change of the array element radiation performance are calculated as follows, and equation (20) is rewritten as follows: (twenty one), In the formula, For the amplitude error of the excitation current, The feed phase error is caused by the temperature drift of the phase shifter and attenuator performance. The amplitude error is introduced by the mutual coupling of array elements and the coupling with the environment. Phase error introduced by mutual coupling of array elements and coupling with the environment.

[0014] Further, in step (6), the amplitude of the excitation current and the theoretical phase compensation for each antenna element are calculated, which are as follows: (twenty two).

[0015] Furthermore, in step (7), considering the quantization errors of the phase shifter and attenuator in the engineering process, the adaptive actual amplitude and phase compensation amount of the excitation current are obtained: (7a) Considering the number of bits in the digital phase shifter, determine the minimum phase shift of the phase shifter, i.e. ,in, The number of bits in the digital phase shifter; compared to the calculated theoretical phase adjustment. Phase shift of the phase shifter The phase adjustment amount of the antenna array element is given: (twenty three), In the formula, Theoretical phase adjustment amount Divide by the phase shift of the phase shifter The merchants, This is the phase adjustment amount of the actual excitation current of the array element; (7b) Adjust the excitation current amplitude of equation (22) Convert the adjustment amount to dB to determine the normalized excitation current amplitude adjustment amount: (twenty four), The normalized excitation current adjustment for equation (24) is: (25), Determine the minimum step value of the digital attenuator The adjustment amount of the incentive amplitude in equation (25) can be expressed as: (26), Based on equations (23) and (26), the amplitude and phase compensation of the array element excitation current that can be directly used in engineering can be quickly calculated to adaptively calibrate the electrical performance of the active phased array antenna.

[0016] The present invention also provides an online joint calibration device for multi-source errors of an active phased array antenna, comprising: an active phased array antenna body having multiple antenna elements; an independent receiving link and an ADC module arranged behind the antenna elements for acquiring element channel signals; a displacement sensor arranged on the antenna array surface for acquiring strain information of the antenna array surface; a temperature sensor arranged on the antenna array surface for acquiring temperature information of the antenna array surface; and a processor configured to execute the above method.

[0017] In addition, the present invention provides an active phased array antenna system including the above-described device; and a computer-readable storage medium storing thereon a computer program for implementing the above-described method.

[0018] Compared with the prior art, the present invention has the following advantages: 1. The active phased array antenna multi-source error online joint calibration method, device and system provided by the present invention collects antenna temperature and strain information in real time under service conditions, estimates the antenna equivalent channel error matrix, array element position offset and array element feed error, and establishes an electrical performance calculation model of active phased array antenna under the above influencing factors, which can perform online quantitative evaluation of the electrical performance of active phased array antenna under operating conditions; 2. This invention deeply reveals the cross-domain coupling mechanism by which thermal loads induce nonlinear structural deformation of the array surface, thereby altering the spatial distribution of array elements and triggering dynamic mutual coupling effects, ultimately leading to beam distortion. By constructing an iterative analysis framework, it focuses on solving the quantitative challenge of the interaction between thermal deformation and mutual coupling impedance mismatch, realizing the mapping from changes in the underlying physical structural field to the top-level electrical parameters. This provides crucial theoretical support for the high-precision real-time compensation and environmentally adaptable design of precision phased array antennas.

[0019] The present invention will now be described in further detail with reference to the accompanying drawings. Attached Figure Description

[0020] Figure 1 This is a flowchart of an online joint calibration method for multi-source errors of an active phased array antenna according to the present invention; Figure 2 This is a structural diagram of an active phased array antenna. Figure 3 This is a structural dimension diagram of an active phased array antenna; Figure 4 This is a schematic diagram of the independent receiving link and ADC module layout; Figure 5 This is a schematic diagram of the arrangement of temperature and displacement sensors on the array antenna surface; Figure 6 This is the interpolated temperature field distribution diagram of the antenna array. Figure 7 This is a diagram showing the displacement field distribution of the reconstructed antenna array. Figure 8(a) and Figure 8(b) show the amplitude of the excitation current and the phase compensation amount of the array element, respectively. Figure 9 This is the radiation pattern of the active phased array antenna before and after compensation.

[0021] Among them, 1 is the antenna array element, 2 is the array panel, 3 is the feeding system, 4 is the independent receiving link and ADC module, and 5 is the placement point of the temperature sensor and displacement sensor. Detailed Implementation

[0022] The present invention will be further described in detail below with reference to specific embodiments, but the implementation of the present invention is not limited thereto.

[0023] Reference Figure 1 This invention provides an online joint calibration method for multi-source errors in active phased array antennas. The specific steps are as follows: Step 1: Determine the structural parameters and material properties of the active phased array antenna.

[0024] See Figure 2 and Figure 3 The structural parameters of the active phased array antenna include the number and spacing of the antenna elements 1 distributed on the array panel 2, the distribution position of the feed system 3, and the position coordinates of the temperature sensor; the material properties include the specific heat capacity of the material. thermal conductivity and density .

[0025] Step 2, execute the following three calibration paths: Calibration Path A: 1) An independent receiving link and ADC module 4 are arranged behind the antenna array elements to collect the array element channel signals.

[0026] An independent receiving link and ADC module 4 are arranged behind the antenna array elements, such as Figure 4 As shown.

[0027] The original signal is down-converted to a 1GHz intermediate frequency (IF) signal using a local oscillator (LO) circuit. A high-speed AD converter is used to acquire each signal and transmit it to the FPGA module. Then, the signal is down-converted to baseband (BB) in the FPGA. After preliminary filtering, the processed baseband I / Q data is transmitted to the host computer.

[0028] 2) Estimate the IQ imbalance gain / phase error of each channel based on the signal blind compensation algorithm.

[0029] According to the processed number Baseband sampling signal with IQ imbalance and image interference acquired by the path , ,in, Total number of channels This represents the nth data point in the digital signal stream. First, construct a string of length... FIR filter The formula for calculating the output of the filter is as follows: (1), Then on The statistical properties were examined, and the following adaptive formula was used to... Update: (2), In the formula, Step size, After the algorithm converges, the FIR filter automatically learns the inverse function of the hardware error, and the output... This eliminates the I / Q imbalance.

[0030] 3) Estimate the equivalent channel error matrix based on the GPC calibration algorithm.

[0031] (a) Place a transmitter in the far field of the phased array antenna to transmit a continuous wave (CW), and select a set of sparse angles. At each angle, the signal received by the phased array antenna is compensated for I / Q imbalance according to step (3) to ensure data purity.

[0032] (b) The acquired time-domain signal , Perform a Discrete Fourier Transform (DFT) to obtain the frequency domain signal. , It is a complex array of length N, where each element represents a specific frequency component. The phase value of the signal is extracted at the CW frequency point using the following formula: (3), The total phase calculated by formula (3) consists of two parts: the geometric phase determined by the antenna position and the total phase calculated by formula (3). Phase error, including element mutual coupling and environmental coupling. in For the spacing between array elements, λ is the wavelength. The calculation formula is as follows: (4), (c) Calculate the time-domain sequence of the signal The root mean square (RMS) value, after normalization, yields the amplitude gain deviation of each channel relative to the reference: (5); (d) Using spline interpolation algorithm to obtain the gain error curve of sparse mesh and phase error curve A smooth fit is performed to generate error data for a high-density network, and finally the obtained error is encapsulated into a matrix. The specific form is as follows: (6).

[0033] Calibration Path B: 1) Arrange displacement sensors on the antenna array.

[0034] Displacement sensors are placed at point 5 on the phased array antenna surface, where temperature and displacement sensors are located. The specific locations are as follows: Figure 5 As shown.

[0035] 2) Based on the antenna array displacement acquisition information, the array displacement field is reconstructed using finite element shape functions.

[0036] (a) Assuming the antenna array is discretized into several elements, for a certain element Let the coordinates of any point within the unit be... The displacement vector at that point is ,like Figure 6 As shown.

[0037] According to finite element theory, displacements within an element can be represented by nodal displacement vectors. And shape function matrix To indicate: (7), Because the raw data measured by the sensor is strain It is the derivative function of the displacement, and the differential operator is denoted as . : (8), Substituting equation (7) into equation (8) yields: (9), Define the strain matrix Then we have: (10); (b) According to the first The coordinates are The strain value measured on the sensor , ,in Given the total number of displacement sensors, for each measuring point, the following can be listed: (11), Wherein, global node displacement vector For local units The mapping.

[0038] All Solving the simultaneous equations of the sensors, we obtain a matrix form: (12), in, It is a column vector of all sensor data; The unknown degrees of freedom of all nodes in the structure; It is a transformation matrix, derived from the strain matrix of each measurement point. It is assembled.

[0039] Since strain is the derivative of displacement, pure strain data cannot determine the displacement of a rigid body. Therefore, boundary conditions must be introduced, assuming a sufficiently large number of sensors are deployed (the number of sensors...). Greater than the number of degrees of freedom of the unknown nodes In this case, the least squares method is used to solve the problem. (13), Find the nodal displacements Then, the displacement at any position on the plane can be calculated according to formula (7).

[0040] 3) Extract the position error of the antenna array elements, and calculate the spatial phase error of the array antenna based on the position error of the array elements.

[0041] For a linear array, the relative position error at the array element is calculated according to step (6). The spatial phase error of the array antenna is calculated as follows: (14), in, The free space wave constant, The wavelength of electromagnetic waves, This represents the positional error of the array elements. The unit vector in the direction of the far-field observation point. These are the unit vectors on the two coordinate axes, respectively. For pitch angle, The azimuth angle is assumed to be used because the research object of this invention is a linear array. .

[0042] Calibration path C: 1) Arrange temperature sensors on the antenna array.

[0043] Temperature sensors are placed at point 5 on the phased array antenna surface, where temperature and displacement sensors are located. The specific locations are as follows: Figure 5 As shown.

[0044] 2) Interpolate the array temperature field based on the temperature acquisition information and determine the temperature field distribution of the power supply system.

[0045] According to the antenna array layout, the first Temperature information collected by a temperature sensor is set as follows: , ,in, Given the total number of temperature sensors, the temperature field of the radome structure is interpolated using the following interpolation function, and the result is as follows: Figure 7 As shown.

[0046] (15), (16), in, and The first The temperature sensor and the first The position coordinates of the location that needs to be interpolated; For the first Temperature values ​​measured at each location For the antenna array... Temperature at each location Weighting factors; To prevent the setting of tiny non-zero values ​​when the measurement point and interpolation point are the same, To control the factors that influence the weights based on distance, To control the weighting factor Factors.

[0047] 3) Extract the T / R component temperature values ​​corresponding to the array elements, and calculate the excitation amplitude and phase error of the array elements based on the device temperature drift performance.

[0048] Based on the effect of temperature on the amplitude of the excitation current: (17), In the formula, For array surface temperature, To normalize the excitation amplitude error, the amplitude error of the excitation current can be expressed as: ,in This represents the maximum value of the excitation current amplitude; Based on the test results and data analysis, the phase error of the array element excitation current was obtained. for: (18).

[0049] Step 3: Perform time synchronization and coordinate registration on the error terms obtained in step (2).

[0050] Step 4: Establish an electromechanical-thermal coupling model under multi-source error and calculate the electrical performance of the phased array antenna in service.

[0051] Ideally, the radiation pattern function of a linear array antenna at a distant observation point is: (19), in, This is the deflection angle; The initial excitation current amplitude of the array element. The initial excitation current phase of the array element. The wave constant; This is the radiation pattern function of the radiating element.

[0052] Based on the equivalent channel error matrix obtained from calibration path A in step (2), the spatial phase error obtained from calibration path B, and the array element excitation amplitude and phase error obtained from calibration path C, the radiation pattern function of the far-field observation point of the linear array antenna in actual operation can be established: (20).

[0053] Step 5: Calculate the amplitude error and phase error of the equivalent excitation of each array element relative to the nominal excitation.

[0054] By comparing the radiation pattern function, the amplitude change rate and phase change of the array element radiation performance are calculated as follows, and equation (20) is rewritten as follows: (twenty one), In the formula, For the amplitude error of the excitation current, The feed phase error is caused by the temperature drift of the phase shifter and attenuator performance. The amplitude error is introduced by the mutual coupling of array elements and the coupling with the environment. Phase error introduced by mutual coupling of array elements and coupling with the environment.

[0055] Step 6: Calculate the theoretical element current amplitude / phase compensation amount.

[0056] Calculate the theoretical compensation amounts for the excitation current amplitude and phase of each antenna element, which are as follows: (twenty two).

[0057] Step 7: Considering the quantization error of the phase shifter / attenuator, obtain the quantized actual excitation current amplitude and phase compensation amount.

[0058] Considering the quantization errors of the phase shifter and attenuator in the engineering process, the actual amplitude and phase compensation of the adaptive excitation current are obtained: (a) Considering the number of bits in the digital phase shifter, determine the minimum phase shift of the phase shifter, i.e. ,in, The number of bits in the digital phase shifter; compared to the calculated theoretical phase adjustment. Phase shift of the phase shifter The phase adjustment amount of the antenna array element is given: (twenty three), In the formula, Theoretical phase adjustment amount Divide by the phase shift of the phase shifter The merchants, This is the phase adjustment amount of the actual excitation current of the array element; (b) Adjust the excitation current amplitude of equation (22) Convert the adjustment amount to dB to determine the normalized excitation current amplitude adjustment amount: (twenty four), The normalized excitation current adjustment for equation (24) is: (25), Determine the minimum step value of the digital attenuator The adjustment amount of the incentive amplitude in equation (25) can be expressed as: (26), Based on equations (23) and (26), the amplitude and phase compensation of the array element excitation current that can be directly used in engineering can be quickly calculated to adaptively calibrate the electrical performance of the active phased array antenna.

[0059] In summary, the online joint calibration method for multi-source errors of active phased array antennas proposed in this invention collects antenna temperature and strain information in real time under service conditions by arranging temperature and displacement sensors on the phased array antenna surface. It obtains antenna surface displacement field information through a reconstruction algorithm and temperature field distribution of the array antenna through an interpolation algorithm. This method predicts the antenna's equivalent channel error matrix, element position offset, and element feed error, establishing an electrical performance calculation model for the active phased array antenna under the influence of these factors. Based on this model, the required excitation current amplitude and theoretical phase adjustment are calculated. Simultaneously, considering the quantization errors of commonly used digital phase shifters and attenuators in engineering, the actual adjustment amounts of the element excitation current amplitude and phase are given. This method is used for online calibration of the antenna's electrical performance and has significant engineering application value.

[0060] The online joint calibration method for multi-source errors of active phased array antennas proposed in this invention is verified through the following simulation experiments: 1. Determine the structural parameters and material properties of the active phased array antenna, and arrange temperature sensors and displacement sensors on the antenna array surface.

[0061] like Figure 2 The diagram shows the structure of a missile-borne active phased array antenna. The specific dimensions of the active phased array antenna are as follows: Figure 3 As shown, the antenna array is a linear array with a length of 0.5m. A total of 8 array elements are arranged on the antenna array, with a spacing between the elements of [missing information]. The operating frequency is 2.5 GHz, and the initial excitation current of the array elements is of equal amplitude and in-phase distribution. The antenna array material is FR4, and temperature sensors and displacement sensors are respectively arranged on the antenna array surface, such as... Figure 4 As shown in Table 1, the temperature acquisition information and the surface strain information are as follows. Table 1. Information Acquired by Active Phased Array Antenna Sensors

[0062] 2. Reconstruct the array surface displacement field based on strain information, interpolate the array surface temperature field based on temperature acquisition information, and calculate the spatial phase error of the array antenna and the amplitude and phase error of the array element excitation current.

[0063] Based on the strain acquisition information of the antenna array in Table 1, the displacement field of the entire array is reconstructed as follows: Figure 6 As shown, the position error of the array elements is extracted, and the spatial phase error of the antenna is calculated.

[0064] Based on the temperature data collected from the antenna array in Table 1, the temperature field of the entire array is interpolated, as follows: Figure 7 As shown, the temperatures of the phase shifter and attenuator are extracted, and the amplitude and phase error of the antenna array element excitation current are calculated based on the device temperature drift performance, as shown in Equations (17) and (18).

[0065] 3. Correct the signal I / Q imbalance according to the signal blind calibration algorithm, and estimate the equivalent error matrix containing array mutual coupling and environmental coupling error information based on the GPC calibration algorithm.

[0066] The mutual coupling between array elements is simulated using the property that the greater the distance between the Toplitz matrices, the closer the coupling becomes, and a random gain is applied to each channel. Multiplication and phase deviation To simulate the actual channel gain / phase error. Then, blind source I / Q imbalance compensation is performed on the signal according to equations (1) and (2), and the compensation result is shown in Figure 8(a).

[0067] After obtaining the I / Q balanced signal, the channel gain / phase error matrix containing the mutual coupling information of the array elements is calculated using the GPC algorithm according to formula (5). The calibration result is shown in Figure 8(b).

[0068] 4. Establish an electromechanical-thermal coupling model under multi-source error and calculate the electrical performance of the active phased array antenna in actual operation; Based on the spatial phase error of the antenna, the amplitude and phase error of the antenna array element excitation current, and the channel gain / phase error matrix obtained from points two and three, an electromechanical-thermal coupling model under multi-source error can be established, as shown in Equation 20. Using this model, the electrical performance of the active phased array antenna under actual working conditions can be calculated.

[0069] 5. Considering the quantization error of the phase shifter and attenuator in the project, calculate the actual amplitude and phase compensation of the adaptive excitation current.

[0070] Based on the actual working conditions of the active phased array antenna, the online joint calibration method of the phased array antenna is verified. A 6-phase shifter commonly used in engineering is adopted, and the minimum step value of the attenuator is 0.5dB. The excitation current amplitude and phase compensation of the active phased array antenna elements are calculated according to Equations (23) and (26). Figure 9 The radiation patterns of the active phased array antenna before and after compensation are given, and Table 2 lists the corresponding electrical performance indicators.

[0071] Table 2 Comparison of Electrical Performance Indicators of Missile-borne Active Phased Array Antennas

[0072] 6. Results Analysis analyze Figure 9As shown in Table 2, the electrical performance of the active phased array antenna deteriorates due to the effects of element mutual coupling, antenna feed error, and position offset. Specifically, the gain loss is 1.65 dB, the first sidelobe level is increased, and the main beam pointing also becomes inaccurate. The proposed joint electrical performance calibration method can effectively improve the antenna's electrical performance, simultaneously compensating for the antenna's gain, first sidelobe level, beamwidth, and main beam pointing. Therefore, this compensation method can determine the corresponding antenna element excitation current amplitude and phase compensation amount based on real-time channel data, displacement, and temperature values ​​collected by the active phased array antenna during operation, enabling online joint calibration of the active phased array antenna's electrical performance.

[0073] The present invention also provides an online joint calibration device for multi-source errors of an active phased array antenna, comprising: an active phased array antenna body having multiple antenna elements 1; an independent receiving link and an ADC module 4 arranged behind the antenna elements 1 for acquiring element channel signals; a displacement sensor arranged on the antenna array surface for acquiring strain information of the antenna array surface; a temperature sensor arranged on the antenna array surface for acquiring temperature information of the antenna array surface; and a processor configured to execute the above method.

[0074] The processors mentioned above can be general-purpose processors, including central processing units (CPUs), network processors (NPs), etc.; they can also be digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components.

[0075] In addition, the present invention provides an active phased array antenna system, including the above-described device; and a computer-readable storage medium, wherein when the computer program is executed by a processor, it implements the steps of the above-described active phased array antenna multi-source error online joint calibration method.

[0076] Optionally, the computer-readable storage medium may be non-volatile memory (NVM), such as at least one disk storage device.

[0077] Optionally, the computer-readable storage medium may also be at least one storage device located remotely from the aforementioned processor.

[0078] The above description, in conjunction with specific preferred embodiments, provides a further detailed explanation of the present invention. It should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, various simple deductions or substitutions can be made without departing from the concept of the present invention, and all such modifications and substitutions should be considered within the scope of protection of the present invention.

Claims

1. A method for online joint calibration of multi-source errors in an active phased array antenna, characterized in that, Includes the following steps: (1) Obtain the structural parameters and material properties of the active phased array antenna; (2) Execute the following three calibration paths: Calibration Path A: Acquire array element channel signals; Estimate IQ imbalance gain / phase error of each channel based on the signal blind compensation algorithm; Estimate the equivalent channel error matrix based on the GPC calibration algorithm; Calibration Path B: Collect antenna array displacement information, reconstruct the array displacement field based on finite element shape functions; extract the position error of antenna elements, and calculate the spatial phase error of the array antenna based on the position error of the elements; Calibration Path C: Collect antenna array surface temperature information, interpolate the array surface temperature field, determine the temperature field distribution of the feed system; extract the T / R component temperature values ​​corresponding to the array elements, and calculate the array element excitation amplitude and phase error based on the device temperature drift performance; (3) Perform time synchronization and coordinate registration on the error terms obtained in step (2); (4) Establish an electromechanical-thermal coupling model under multi-source error and calculate the electrical performance of the phased array antenna under service conditions; (5) Calculate the amplitude error and phase error of the equivalent excitation of each array element relative to the nominal excitation; (6) Calculate the theoretical array element current amplitude / phase compensation amount; (7) Considering the quantization error of the phase shifter / attenuator, the actual excitation current amplitude and phase compensation amount after quantization is obtained.

2. The method for online joint calibration of multi-source errors in an active phased array antenna according to claim 1, characterized in that, In step (1), the structural parameters of the active phased array antenna include the number of antenna elements, spacing, distribution of the feed system, and coordinates of the temperature sensor; the material properties include the specific heat capacity of the array panel material. thermal conductivity and density .

3. The method for online joint calibration of multi-source errors in an active phased array antenna according to claim 1, characterized in that, In step (2), calibration path A involves acquiring array element channel signals, specifically including: The original signal is down-converted to a 1GHz intermediate frequency signal using a local oscillator circuit. A high-speed AD converter is used to acquire each signal and transmit it to the FPGA module. Then, the signal is down-converted to baseband in the FPGA. After preliminary filtering, the processed baseband I / Q data is transmitted to the host computer. In step (2), calibration path A estimates the IQ imbalance gain / phase error of each channel according to the signal blind compensation algorithm, specifically including: According to the processed number Baseband sampling signal with IQ imbalance and image interference acquired by the path , ,in, Total number of channels This represents the nth data point in the digital signal stream; first, construct a string of length... FIR filter The output of the filter is calculated using the following formula: (1) Then on The statistical properties were examined, and the following adaptive formula was used to... Update: (2) In the formula, Step size, After the algorithm converges, the FIR filter automatically learns the inverse function of the hardware error, and the output... This eliminates the I / Q imbalance; In step (2), calibration path A, the equivalent channel error matrix is ​​estimated according to the GPC calibration algorithm, specifically including: (a) Place a transmitter in the far field of the phased array antenna to transmit a continuous wave (CW), and select a set of sparse angles. I / Q imbalance compensation is performed on the signal received by the phased array antenna at each angle to ensure data purity; (b) The acquired time-domain signal , Perform a discrete Fourier transform to obtain the frequency domain signal. , It is a complex array of length N, where each element represents a specific frequency component; the phase value of the signal is extracted at the CW frequency point using the following formula: (3)， The total phase calculated by formula (3) consists of two parts: the geometric phase determined by the antenna position and the total phase calculated by formula (3). Phase error, including element mutual coupling and environmental coupling. in For the spacing between array elements, For wavelength, The calculation formula is as follows: (4)； (c) Calculate the time-domain sequence of the signal The root mean square value, after normalization, yields the amplitude gain deviation of each channel relative to the reference: (5)； (d) Using spline interpolation algorithm to obtain the gain error curve of sparse mesh and phase error curve A smooth fit is performed to generate error data for a high-density network, and finally the obtained error is encapsulated into a matrix. The specific form is as follows: (6)。 4. The method for online joint calibration of multi-source errors in an active phased array antenna according to claim 1, characterized in that, In step (2), the calibration path B specifically includes reconstructing the antenna array displacement field: (a) Assuming the antenna array is discretized into several elements, for a certain element Let the coordinates of any point within the unit be... The displacement vector at that point is According to finite element theory, displacements within an element can be represented by nodal displacement vectors. And shape function matrix To indicate: (7)， Because the raw data measured by the sensor is strain It is the derivative function of the displacement, and the differential operator is denoted as . : (8) Substituting equation (7) into equation (8) yields: (9)， Define the strain matrix Then we have: (10)； (b) According to the first The coordinates are The strain value measured on the sensor , ,in Given the total number of displacement sensors, for each measuring point, the following can be listed: (11)， Wherein, the global node displacement vector For local units Mapping; All Solving the simultaneous equations of the sensors, we obtain a matrix form: (12)， in, It is a column vector of all sensor data; It is a column vector containing the unknown degrees of freedom of all nodes; It is a transformation matrix, derived from the strain matrix of each measurement point. Assembled; Since strain is the derivative of displacement, pure strain data cannot determine the displacement of a rigid body. Therefore, boundary conditions must be introduced, assuming a sufficiently large number of sensors are deployed. Greater than the number of degrees of freedom of the unknown nodes In this case, the least squares method is used to solve the problem: (13)， Find the nodal displacements Then, the displacement at any position on the plane can be calculated according to formula (7); In step (2), in calibration path B, for a linear array, the relative position error at the array element is calculated based on calibration path B. The spatial phase error of the array antenna is calculated as follows: (14)， in, The free space wave constant, The wavelength of electromagnetic waves, This represents the positional error of the array elements. The unit vector in the direction of the far-field observation point. These are the unit vectors on the two coordinate axes, respectively. This refers to the pitch angle.

5. The method for online joint calibration of multi-source errors in an active phased array antenna according to claim 1, characterized in that, In the calibration path C of step (2), according to the antenna array arrangement, the first... Temperature information collected by a temperature sensor is set as follows: , ,in, Given the total number of temperature sensors, the temperature field of the radome structure is interpolated using the following interpolation function: (15) (16)， in, and The first The temperature sensor and the first The position coordinates of the location that needs to be interpolated; For the first Temperature values ​​measured at each location For the antenna array Temperature at each location Weighting factors; To prevent the setting of tiny non-zero values ​​when the measurement point and interpolation point are the same, To control the factors that influence the weights based on distance, To control the weighting factor Factors; In step (2), the specific method for calculating the amplitude and phase error of the array element excitation based on the device temperature drift performance in calibration path C is as follows: Based on the effect of temperature on the excitation current amplitude, the normalized excitation amplitude error is calculated using the following formula: (17)， In the formula, For array surface temperature, To normalize the excitation amplitude error, the amplitude error of the excitation current can be expressed as: ,in This represents the maximum value of the excitation current amplitude; Based on the effect of temperature on the phase of the excitation current, the phase error is calculated using the following formula. for: (18)。 6. The method for online joint calibration of multi-source errors in an active phased array antenna according to claim 1, characterized in that, Step (4) specifically includes: Ideally, the radiation pattern function of a linear array antenna at a distant observation point is: (19)， in, This is the deflection angle; The initial excitation current amplitude of the array element. The initial excitation current phase of the array element. The wave constant; The radiation pattern function of the radiating element; Based on the equivalent channel error matrix obtained from calibration path A, the spatial phase error obtained from calibration path B, and the element excitation amplitude and phase error obtained from calibration path C, the radiation pattern function of the far-field observation point of the linear array antenna in actual operation can be established: (20)， By comparing the radiation pattern function, the amplitude change rate and phase change of the array element radiation performance are calculated as follows, and equation (20) is rewritten as follows: (21)， In the formula, For the amplitude error of the excitation current, The feed phase error is caused by the temperature drift of the phase shifter and attenuator performance. The amplitude error is introduced by the mutual coupling of array elements and the coupling with the environment. Phase error introduced by mutual coupling of array elements and coupling with the environment.

7. The method for online joint calibration of multi-source errors in an active phased array antenna according to claim 1, characterized in that, In step (6), the amplitude of the excitation current and the theoretical phase compensation for each antenna element are calculated, which are as follows: (22)。 8. The method for online joint calibration of multi-source errors in an active phased array antenna according to claim 1, characterized in that, In step (7), considering the quantization errors of the phase shifter and attenuator in the engineering process, the adaptive actual amplitude and phase compensation amount of the excitation current are obtained: (7a) Considering the number of bits in the digital phase shifter, determine the minimum phase shift of the phase shifter, i.e. ,in, The number of bits in the digital phase shifter; compared to the calculated theoretical phase adjustment. Phase shift of the phase shifter The phase adjustment amount of the antenna array element is given: (23)， In the formula, Theoretical phase adjustment amount Divide by the phase shift of the phase shifter The merchants, This is the phase adjustment amount of the actual excitation current of the array element; (7b) Adjust the excitation current amplitude of equation (22) Convert the adjustment amount to dB to determine the normalized excitation current amplitude adjustment amount: (24)， The normalized excitation current adjustment for equation (24) is: (25)， Determine the minimum step value of the digital attenuator The adjustment amount of the incentive amplitude in equation (25) can be expressed as: (26)， Based on equations (23) and (26), the amplitude and phase compensation of the array element excitation current that can be directly used in engineering can be quickly calculated to adaptively calibrate the electrical performance of the active phased array antenna.

9. A multi-source error online joint calibration device for an active phased array antenna, characterized in that, include: An independent receiving link and ADC module are arranged behind the antenna array elements to collect array element channel signals; Displacement sensors are arranged on the antenna array to collect strain information of the antenna array. Temperature sensors are placed on the antenna array to collect temperature information of the antenna array. The processor is configured to perform the method of any one of claims 1 to 8.

10. An active phased array antenna system, characterized in that, This includes the online joint calibration device for multi-source errors of active phased array antennas as described in claim 9.

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