Methods, systems, equipment, and media for dynamic compensation of antenna polarization and line-of-sight locking under maneuvering flight conditions.

Abstract

This invention relates to a method, system, equipment, and medium for dynamic compensation of the polarization surface and line-of-sight locking of a test antenna under maneuvering flight conditions, belonging to the field of radar antenna testing technology. The method includes: acquiring the instantaneous three-dimensional attitude angles and three-dimensional spatial coordinates of the UAV; calculating the theoretical spatial pointing angle of the test antenna relative to the phase center of the ground-based radar under test based on the absolute spatial coordinates and instantaneous three-dimensional spatial coordinates; performing differential control processing on the instantaneous three-dimensional attitude angles and the theoretical spatial pointing angle under the same geodetic reference, and controlling the main lobe line-of-sight of the test antenna to lock to the phase center of the ground-based radar under test based on the obtained steering compensation control quantity; and controlling the test antenna to rotate in the opposite direction based on the instantaneous roll angle in the instantaneous three-dimensional attitude angles to compensate for the dynamic parallelism between the polarization surface of the test antenna and the polarization reference plane. This invention reduces polarization crosstalk and amplitude drop errors caused by airframe disturbances, improving the reliability of high-precision in-situ testing.

Description

Technical Field

[0001] This invention relates to the field of radar antenna testing technology, and in particular to a method, system, device, and medium for dynamic compensation of the polarization surface and line-of-sight locking of a test antenna under maneuvering flight conditions. Background Technology

[0002] With the development of antenna testing technology, using UAVs to carry radio frequency measurement payloads for in-situ testing of large ground-based radars has become an important means to overcome the limitations of traditional indoor anechoic chamber testing. In antenna radiation characteristic evaluation, polarization characteristics, such as horizontal polarization, vertical polarization, and cross-polarization isolation, are core indicators for measuring radar system performance. However, when UAVs perform hovering or trajectory scanning in the air, they are inevitably affected by high-altitude airflow disturbances and the system's own flight control adjustments, resulting in high-frequency and low-frequency attitude fluctuations.

[0003] In traditional testing methods, measurement antennas or probes are typically rigidly fixed to the UAV fuselage or employ only simple damping for vibration reduction. Even a small roll angle, such as 0.5 to 1 degree, causes the polarization vector of the test probe to tilt, resulting in leakage of the originally pure horizontally polarized electromagnetic waves into the vertically polarized channel. Simultaneously, pitch and yaw movements of the fuselage cause the probe's main beam to deviate from the center of the ground-based radar, leading to drastic fluctuations in the received amplitude. These polarization couplings and line-of-sight deviations introduced by mechanical disturbances severely compromise the accuracy of cross-polarization isolation and gain measurements, representing a significant engineering bottleneck in high-precision antenna testing for UAVs.

[0004] Therefore, those skilled in the art urgently need a technical solution that can achieve dynamic compensation of the polarization surface and line-of-sight locking of the test antenna under maneuvering flight conditions. Summary of the Invention

[0005] (a) Technical problems to be solved In view of the above-mentioned shortcomings and deficiencies of the prior art, the present invention provides a method, system, device and medium for dynamic compensation of polarization surface and line-of-sight locking of test antenna under maneuvering flight conditions, which solves the technical problems of polarization crosstalk and line-of-sight deviation caused by the attitude disturbance of UAV fuselage in the prior art.

[0006] (II) Technical Solution To achieve the above objectives, the main technical solutions adopted by the present invention include: In a first aspect, embodiments of the present invention provide a method for dynamic compensation of the polarization surface and line-of-sight locking of a test antenna under maneuvering flight conditions. The method is applied to a UAV test platform equipped with a test antenna and includes: Obtain the instantaneous three-dimensional attitude angles and instantaneous three-dimensional spatial coordinates of the UAV; Based on the absolute spatial coordinates and instantaneous three-dimensional spatial coordinates of the ground-based radar under test, the theoretical spatial pointing angle of the test antenna relative to the phase center of the ground-based radar under test is calculated. Under the same geodetic reference datum, the instantaneous three-dimensional attitude angle and the theoretical spatial pointing angle are differentially controlled, and based on the obtained steering compensation control quantity, the main lobe line of sight of the test antenna is controlled to lock the phase center of the ground-based radar under test. Based on the instantaneous roll angle in the instantaneous three-dimensional attitude angle, the test antenna is controlled to perform a reverse rotation with equal amplitude to compensate for the dynamic parallelism between the polarization surface of the test antenna and the preset polarization reference surface. The line-of-sight locking control and polarization dynamic compensation of the test antenna are set as two decoupled orthogonal control degrees of freedom.

[0007] Optionally, obtaining the instantaneous three-dimensional attitude angles and instantaneous three-dimensional spatial coordinates of the UAV includes: During the UAV flight test, the onboard RTK positioning system and inertial measurement unit are used to simultaneously acquire the UAV's instantaneous three-dimensional spatial coordinates and instantaneous three-dimensional attitude angles, including roll angle, pitch angle and heading angle. Among them, the instantaneous three-dimensional spatial coordinates and instantaneous three-dimensional attitude angles are aligned with hardware timestamps using a unified PPS second pulse signal during acquisition.

[0008] Optionally, based on the absolute spatial coordinates and instantaneous three-dimensional spatial coordinates of the ground-based radar under test, the theoretical spatial pointing angle of the test antenna relative to the phase center of the ground-based radar under test is calculated, including: A local ENU coordinate system is established with the phase center of the ground-based radar under test as the origin. The instantaneous three-dimensional spatial coordinates are converted into relative position vectors in the local ENU coordinate system. The relative position vectors contain position components in three orthogonal directions. The horizontal projection distance is obtained from the horizontal projection component of the relative position vector. Based on the vertical component of the relative position vector and the horizontal projection distance, the theoretical pitch pointing angle of the test antenna relative to the phase center of the ground-based radar under test is calculated. Based on the two horizontal components of the relative position vector, the theoretical azimuth pointing angle of the test antenna relative to the phase center of the ground-based radar under test is calculated. The instantaneous three-dimensional attitude angles are transformed from the body coordinate system to the local ENU coordinate system using a coordinate rotation matrix.

[0009] Optionally, under the same geodetic reference datum, differential control processing is performed on the instantaneous three-dimensional attitude angle and the theoretical spatial pointing angle, and based on the obtained steering compensation control quantity, the main lobe line of sight of the test antenna is controlled to lock the phase center of the ground-based radar under test, including: Based on the real-time differential results between the instantaneous three-dimensional attitude angle of the UAV and the theoretical spatial pointing angle of the test antenna, a feedforward bias control quantity is generated. Based on the real-time phase difference measurement values ​​between the received signals of the same pulse signal from each channel of the array antenna, a feedback correction control quantity is generated, and the feedback correction control quantity is weighted and fused with the feedforward deviation control quantity to obtain the steering compensation control quantity of the test antenna. The steering compensation control quantity is used as the target driving command. After being calculated by the PID control algorithm, it drives the gimbal where the test antenna is located to perform servo motion so that the main lobe line of sight of the test antenna locks the phase center of the ground-based radar under test. Among them, the feedforward deviation control quantity is used to compensate for the spatial pointing deviation of the test antenna caused by the attitude disturbance of the UAV body, and the feedback correction control quantity is used to compensate for the residual pointing error of the main lobe line of the test antenna due to the mechanical error of the gimbal or the residual wind disturbance.

[0010] Optionally, the steering compensation control quantity is used as the target driving command, and after being calculated by the PID control algorithm, it drives the gimbal where the test antenna is located to perform servo motion, so that the main lobe line of sight of the test antenna locks the phase center of the ground-based radar under test, including: Obtain the current motor rotation angle in real time from the internal encoders of the pitch axis motor and yaw axis motor of the gimbal; Using the theoretical spatial pointing angle as the target value of closed-loop control and the current motor rotation angle as the feedback value of closed-loop control, deviation calculation is performed to obtain the pointing angle deviation. The steering compensation control quantity is added to the pointing angle deviation as a feedforward term, and the generated comprehensive control deviation is then subjected to PID calculation to generate the drive control signals for the pitch axis motor and the yaw axis motor. The gimbal servo motor is driven by the drive control signal until the overall control deviation converges to within the preset threshold, and the calibration information of the test antenna main lobe line of sight locking the phase center of the ground-based radar under test is output.

[0011] Optionally, based on the instantaneous roll angle in the instantaneous three-dimensional attitude angle, controlling the test antenna to perform a counter-rotation with equal amplitude to compensate for the dynamic parallelism between the polarization surface of the test antenna and the preset polarization reference surface includes: Extract the instantaneous roll angle and roll rate of change at the current moment from the instantaneous three-dimensional attitude angles; The instantaneous roll angle is inverted and used as the roll compensation control quantity to drive the roll axis motor of the gimbal where the test antenna is located to perform reverse servo control in order to compensate for the dynamic parallelism between the polarization surface and the polarization reference surface of the test antenna. When the instantaneous roll angle rate exceeds the preset angular rate threshold, Kalman filtering is used to predict the roll angle change at the next moment based on the instantaneous roll angle and the roll angle change rate. Based on the change in roll angle and the instantaneous roll angle at the current moment, a lead compensation control quantity is generated to drive a pre-compensation rotation before the instantaneous roll angle is generated.

[0012] Secondly, embodiments of the present invention provide a test antenna polarization surface dynamic compensation and line-of-sight locking system under maneuvering flight conditions, comprising: The perception module is used to acquire the instantaneous three-dimensional attitude angles and instantaneous three-dimensional spatial coordinates of the UAV; The spatial pointing calculation module is used to calculate the theoretical spatial pointing angle of the test antenna relative to the phase center of the ground-based radar under test based on the absolute spatial coordinates and instantaneous three-dimensional spatial coordinates of the ground-based radar under test. The line-of-sight locking module is used to perform differential control processing on the instantaneous three-dimensional attitude angle and the theoretical spatial pointing angle under the same geodetic reference, and control the main lobe line of sight of the test antenna to lock the phase center of the ground-based radar under test based on the obtained steering compensation control quantity. The polarization surface dynamic compensation module is used to control the test antenna to perform a counter-rotation with equal amplitude based on the instantaneous roll angle in the instantaneous three-dimensional attitude angle, so as to compensate for the dynamic parallelism between the polarization surface of the test antenna and the preset polarization reference surface; wherein, the line-of-sight locking control and the polarization surface dynamic compensation of the test antenna are set as two mutually decoupled orthogonal control degrees of freedom.

[0013] Thirdly, embodiments of the present invention provide an electronic device, comprising: At least one processor; and memory that is communicatively connected to at least one processor; The memory stores instructions that can be executed by at least one processor, which are executed by at least one processor to enable the at least one processor to perform the above-described method for dynamic compensation of the polarization surface and line-of-sight locking of a test antenna under maneuvering flight conditions.

[0014] Fourthly, embodiments of the present invention provide a computer-readable storage medium storing computer-executable instructions, which, when executed by a processor, implement the above-described method for dynamic compensation of the polarization surface and line-of-sight locking of a test antenna under maneuvering flight conditions.

[0015] (III) Beneficial Effects The beneficial effects of this invention are as follows: The method for dynamic compensation and line-of-sight locking of the polarization surface of a test antenna under maneuvering flight conditions of this invention, by using the three-dimensional attitude angle of the test antenna mounted on the UAV test platform to give two independent electromagnetic measurement physical meanings of spatial line-of-sight locking and polarization surface inverse compensation, enables the two control channels to form orthogonally decoupled degrees of freedom in three-dimensional space. Compared with the prior art, it significantly reduces the dynamic amplitude ripple and polarization crosstalk caused by wind field disturbances. Without the need for complex post-process digital polarization reconstruction, it directly ensures the metrological accuracy of antenna pattern, absolute gain and cross-polarization isolation measurements at the front-end physical layer. Attached Figure Description

[0016] Figure 1 This is a flowchart illustrating a method for dynamic compensation of the polarization surface and line-of-sight locking of a test antenna under maneuvering flight conditions, provided in an embodiment of the present invention. Figure 2 This is a schematic diagram of the principle of reverse dynamic compensation of polarization surface under body roll disturbance provided in an embodiment of the present invention. Sub-figure (a) is a schematic diagram of the polarization surface being parallel and aligned with the optimal cross isolation. Sub-figure (b) is a schematic diagram of the probe following the tilt and generating polarization mismatch. Sub-figure (c) is a schematic diagram of the gimbal reverse roll compensation probe restoring to horizontal to eliminate cross polarization error. Figure 3 This is a schematic diagram of the spatial relative geometry solution provided in an embodiment of the present invention; Figure 4 This is a schematic diagram of the process of dual-axis line-of-sight locking provided in an embodiment of the present invention; Figure 5 A schematic diagram of a closed-loop PID control loop provided in an embodiment of the present invention; Figure 6 This is a schematic diagram of the process for reverse compensation of a uniaxial polarization surface provided in an embodiment of the present invention; Figure 7 This is a schematic diagram illustrating the process of implementing fuselage monitoring according to an embodiment of the present invention. Detailed Implementation

[0017] To better explain and facilitate understanding of the present invention, the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0018] refer to Figures 1-7As shown in the embodiment of the present invention, a method for dynamic compensation of the polarization surface and line-of-sight locking of a test antenna under maneuvering flight conditions is proposed. This method is applied to a UAV test platform equipped with a test antenna. The method includes: acquiring the instantaneous three-dimensional attitude angle and instantaneous three-dimensional spatial coordinates of the UAV; calculating the theoretical spatial pointing angle of the test antenna relative to the phase center of the ground-based radar under test based on the absolute spatial coordinates and instantaneous three-dimensional spatial coordinates of the ground-based radar under test; performing differential control processing on the instantaneous three-dimensional attitude angle and the theoretical spatial pointing angle under the same geodetic reference, and controlling the main lobe line-of-sight of the test antenna to lock the phase center of the ground-based radar under test based on the obtained steering compensation control amount; controlling the test antenna to perform a counter-rotation with equal amplitude based on the instantaneous roll angle in the instantaneous three-dimensional attitude angle to compensate for the dynamic parallelism between the polarization surface of the test antenna and the preset polarization reference surface; wherein, the line-of-sight locking control and the dynamic compensation of the polarization surface of the test antenna are set as two mutually decoupled orthogonal control degrees of freedom.

[0019] This embodiment utilizes the three-dimensional attitude angle of the test antenna mounted on the UAV test platform to give two independent electromagnetic measurement physical meanings: spatial line-of-sight locking and polarization surface inverse compensation. This allows the two control channels to form orthogonally decoupled degrees of freedom in three-dimensional space. Compared with the prior art, it significantly reduces dynamic amplitude ripple and polarization crosstalk caused by wind field disturbances. Without the need for complex post-processing digital polarization reconstruction, it directly ensures metrological-grade accuracy of antenna pattern, absolute gain, and cross-polarization isolation measurements at the front-end physical layer.

[0020] To better understand the above technical solutions, exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present invention are shown in the drawings, it should be understood that the present invention can be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that the present invention can be understood more clearly and thoroughly, and that the scope of the present invention can be fully conveyed to those skilled in the art.

[0021] Specifically, refer to Figure 1 and Figure 2 As shown in the embodiment of the present invention, a method for dynamic compensation of the polarization surface and line-of-sight locking of a test antenna under maneuvering flight conditions may include the following steps S100 to S400: S100: Obtain the instantaneous three-dimensional attitude angles and instantaneous three-dimensional spatial coordinates of the UAV.

[0022] In this embodiment, during the UAV flight test, the onboard RTK positioning system and inertial measurement unit on the UAV test platform are used to simultaneously acquire the instantaneous three-dimensional spatial coordinates of the UAV and the instantaneous three-dimensional attitude angles including roll angle, pitch angle and heading angle; wherein, the instantaneous three-dimensional spatial coordinates and instantaneous three-dimensional attitude angles are aligned with hardware timestamps using a unified PPS second pulse signal during acquisition.

[0023] S200. Based on the absolute spatial coordinates and instantaneous three-dimensional spatial coordinates of the ground-based radar under test, calculate the theoretical spatial pointing angle of the test antenna relative to the phase center of the ground-based radar under test.

[0024] In this embodiment, since the instantaneous three-dimensional spatial coordinates of the UAV change continuously over time during flight, and the main lobe line of sight of the test antenna needs to always be aligned with the phase center of the ground-based radar under test to ensure the amplitude stability of the received signal, it is necessary to calculate the theoretical spatial pointing angle of the test antenna relative to the phase center of the radar in real time based on the spatial position of the UAV at each moment, as the target input value for subsequent line-of-sight locking control. Specifically, refer to... Figure 3 As shown, step S200 may include the following sub-steps S210 to S250: S210. Establish a local ENU coordinate system with the phase center of the ground-based radar being measured as the origin, and convert the instantaneous three-dimensional spatial coordinates into a relative position vector in the local ENU coordinate system. The relative position vector contains position components in three orthogonal directions.

[0025] Furthermore, the phase center of the ground-based radar under test was calibrated during the radar deployment phase using high-precision geodetic surveying, and its absolute spatial coordinates ( X r , Y r , Z r The system preset parameters are pre-stored in the onboard mission computer. The instantaneous three-dimensional spatial coordinates output in real time by the UAV RTK positioning system are... X u , Y u , Z u The coordinates are longitude, latitude, and altitude values ​​in the geodetic coordinate system. By establishing a local ENU (East-North-Sky) coordinate system with the radar phase center as the origin, the spatial relationship between the two is converted from geodetic coordinates to a relative position vector in rectangular coordinate form, which facilitates angle calculation.

[0026] S220. Obtain the horizontal projection distance based on the horizontal projection component of the relative position vector.

[0027] Furthermore, the horizontal projection distance Rh The calculation formula is: ; In the formula, Δ X = X u - X r Δ Y = Y u - Y r .

[0028] S230. Based on the vertical component of the relative position vector and the horizontal projection distance, calculate the theoretical pitch pointing angle of the test antenna relative to the phase center of the ground-based radar under test.

[0029] Furthermore, the theoretical pitch angle Pitch target The calculation formula is: Pitch target = arctan (Δ Z / R h ); In the formula, arctan Let Δ be the arctangent function. Z = Z u -Z r .

[0030] S240. Based on the two horizontal components of the relative position vector, calculate the theoretical azimuth pointing angle of the test antenna relative to the phase center of the ground-based radar under test.

[0031] Furthermore, the theoretical azimuth pointing angle Yaw target The calculation formula is: Yaw target =arctan( Δ Y / Δ X) .

[0032] S250. Transform the instantaneous three-dimensional attitude angle from the body coordinate system to the local ENU coordinate system using a coordinate rotation matrix.

[0033] Furthermore, since the instantaneous three-dimensional attitude angles output by the airborne inertial measurement unit are defined in the body coordinate system, while the calculated theoretical pitch and azimuth angles are defined in the geodetic reference system, the two coordinate systems are different and cannot be directly used for differential calculations. Therefore, it is necessary to construct a coordinate rotation matrix from the body coordinate system to the geodetic coordinate system based on the UAV's heading, pitch, and roll angles, and uniformly transform the instantaneous three-dimensional attitude angles to the geodetic reference system of the local ENU coordinate system. This ensures that the reference system of all angle quantities is consistent in subsequent differential control processing and eliminates the systematic pointing deviation introduced by the inconsistency of coordinate system references.

[0034] S300, under the same geodetic reference datum, performs differential control processing on the instantaneous three-dimensional attitude angle and the theoretical spatial pointing angle, and based on the obtained steering compensation control quantity, controls the main lobe line of sight of the test antenna to lock the phase center of the ground-based radar under test.

[0035] In this embodiment, since single feedforward control can only compensate for predictable attitude disturbances but cannot eliminate the nonlinear errors of the gimbal drive mechanism and the residual random wind disturbances not fully captured by the inertial measurement unit, this embodiment adopts a control strategy of feedforward deviation control + phase difference feedback correction weighted fusion to balance dynamic response speed and steady-state tracking accuracy. Specifically, refer to... Figure 4 As shown, step S300 may include the following sub-steps S310 to S330: S310. Based on the real-time differential results of the instantaneous three-dimensional attitude angle and the theoretical spatial pointing angle of the UAV, a feedforward deviation control quantity is generated.

[0036] Furthermore, the feedforward bias control is used to compensate for the spatial pointing deviation of the test antenna caused by UAV attitude disturbances. Its physical meaning is that if there is an angle between the current attitude of the UAV and the theoretical pointing angle, the three-axis stabilization gimbal where the test antenna is located needs to compensate for this angle so that the antenna's main lobe points towards the target direction. The feedforward bias control is an open-loop feedforward system, which has the advantages of fast response speed and no hysteresis accumulation, enabling real-time compensation for high-frequency attitude disturbances of the UAV. The formula for calculating the feedforward bias control is: Δ Pitch = Pitch target - Pitch u ; Δ Yaw = Yaw target - Yaw u ; In the formula, Δ Pitch For pitch compensation control, Δ Yaw This is the heading compensation control quantity. Pitchu The instantaneous pitch angle of the drone fuselage. Yaw u The instantaneous heading angle of the drone fuselage.

[0037] S320. Based on the real-time phase difference measurement values ​​between the received signals of the same pulse signal from each channel of the array antenna, a feedback correction control quantity is generated, and the feedback correction control quantity is weighted and fused with the feedforward deviation control quantity to obtain the steering compensation control quantity of the test antenna.

[0038] Furthermore, due to gaps or flexible deformation in the gimbal drive mechanism, or residual wind disturbance not fully captured by the IMU, even if the feedforward command has been executed, the antenna main lobe line of sight may still deviate from the radar phase center, resulting in residual pointing error. To address this, the embodiment introduces a feedback closed loop based on electromagnetic wave phase difference measurement. The test antenna receives electromagnetic wave signals from the radiation source of the ground-based radar under test. When the main lobe line of sight of the test antenna is precisely aligned with the radar phase center, the phase of the electromagnetic waves received on the antenna aperture surface exhibits a uniform distribution; when the line of sight deviates, a linear phase gradient will appear in the phase distribution along the deviation direction. Therefore, by detecting the phase difference between the received signals from different receiving channels in the antenna array, the residual pointing error due to the line of sight deviating from the radar phase center can be calculated. Specifically, the test antenna is configured as an array containing multiple receiving channels. The received signals from each channel are down-converted by the RF front-end and then sent to a phase comparator, which outputs the phase difference measurement value Δ in real time. φ The phase difference Δ φ Residual pointing deviation Δ θ There exists a definite proportional relationship: Δ θ = k ×Δ φ ,in k This is the proportionality coefficient. Subsequently, the measured phase difference value is used as an error feedback signal to generate a feedback correction control quantity. This feedback correction control quantity is used to compensate for the residual pointing error caused by the main lobe line of sight of the test antenna deviating from the phase center of the ground-based radar under test due to gimbal mechanical errors or residual wind disturbance. Finally, the feedback correction control quantity and the feedforward deviation control quantity are weighted and fused to obtain the steering compensation control quantity of the test antenna: Δ Pitch'=α× Δ Pitch+β× Δ Pitch ； Δ Yaw'=α× Δ Yaw+β× Δ Yaw ; In the formula, Δ Pitch Δ Yaw These are the pitch and azimuth feedback correction control values ​​calculated based on the phase difference measurements. α and β For the weighted fusion coefficient, satisfying α + β =1.

[0039] S330: The steering compensation control quantity is used as the target driving command. After being calculated by the PID control algorithm, it drives the gimbal where the test antenna is located to perform servo motion so that the main lobe line of sight of the test antenna locks the phase center of the ground-based radar under test.

[0040] Furthermore, since the steering compensation control quantity is a target command in the angle domain, and the gimbal motor actually experiences nonlinear factors such as transmission friction, backlash, and elastic deformation during execution, directly mapping the angle command to the motor drive signal cannot guarantee the consistency between the actual pointing angle and the target command. Simultaneously, there is a mapping relationship between the actual rotation angle of the motor rotor and the final pointing angle of the antenna due to the mechanical transmission ratio and linkage mechanism, requiring real-time acquisition of the actual position feedback from the execution end to form closed-loop control. Therefore, this embodiment further employs a dual feedback mechanism of feedforward compensation and encoder feedback. The steering compensation control quantity is superimposed as a feedforward term onto the input of the closed-loop control to achieve advance compensation for attitude disturbances; simultaneously, the current rotation angle fed back in real-time by the motor encoder is used as the feedback value for closed-loop control to achieve closed-loop correction of residual deviations. Both work together to ensure the speed and accuracy of the line-of-sight pointing. Specifically, refer to... Figure 5 As shown, step S330 may include the following sub-steps S331 to S334: S331. Obtain the current motor rotation angle fed back in real time by the internal encoders of the pitch axis motor and yaw axis motor of the gimbal.

[0041] To further explain, both the pitch axis motor and yaw axis motor of the three-axis stabilization gimbal have built-in high-precision magnetoelectric or photoelectric angle encoders. These encoders measure the mechanical rotation angle of the motor rotor in real time. This current motor rotation angle reflects the actual pointing angle of the gimbal and the test antenna at the current moment, serving as the feedback input for closed-loop control. This is different from the feedback correction control based on the phase difference measurement value mentioned above. The former is motion domain feedback, used to compensate for the transmission error and mechanical backlash of the actuator itself; the latter is outer-loop electromagnetic domain feedback, used to correct the spatial deviation of the pointing target.

[0042] S332. Using the theoretical spatial pointing angle as the target value of closed-loop control and the current motor rotation angle as the feedback value of closed-loop control, perform deviation calculation to obtain the pointing angle deviation.

[0043] To further explain, the formula for calculating the pointing angle deviation is: θ Pitch = Pitchtarget -θ Pitch ; θ Yaw = Yaw target -θ Yaw ; In the formula, θ Pitch This is the pitch pointing angle deviation. θ Yaw This refers to the deviation of the azimuth pointing angle. θ Pitch The angle of rotation of the pitch axis motor. θ Yaw This refers to the rotation angle of the yaw axis motor.

[0044] S333: The steering compensation control quantity is superimposed on the pointing angle deviation quantity as a feedforward term, and the generated comprehensive control deviation is calculated by PID to generate the drive control signals for the pitch axis motor and the yaw axis motor.

[0045] To further explain, the steering compensation control variable is added as a feedforward term to the steering angle deviation to form the overall control deviation: Δ e Pitch =θ Pitch + Δ Pitch ; Δ e Yaw =θ Yaw + Δ Yaw' ; In the formula, Δ e Pitch For pitch control deviation, Δ e Yaw This is for comprehensive control of azimuth deviation.

[0046] Subsequently, the overall control deviation will be adjusted. e ( t ) = [Δ e Pitch ,Δ e Yaw The input is to a PID controller. The PID controller performs weighted calculations on the current deviation, historical cumulative deviation, and deviation change rate according to the proportional, integral, and derivative channels, respectively, and generates drive control signals for the pitch axis motor and yaw axis motor according to the following control law: u ( t )= Kp × e ( t )+ Ki ×∫ e ( t ) dt + Kd × de ( t ) / dt ; In the formula, the proportional term Kp×e ( t This is used to provide a real-time response to the current integrated control deviation; the larger the deviation, the stronger the output drive signal. Kp Proportional gain coefficient; Integral term Ki× ∫ e ( t ) dt This is used to accumulate and integrate historical deviations, eliminating steady-state errors caused by static friction and transmission backlash in the gimbal mechanism, and ensuring that the line of sight eventually converges to the target direction. Ki The integral gain coefficient; the differential term Kd×de ( t ) / d t It is used to predict the rate of change of deviation. When the deviation increases rapidly, it outputs a reverse suppression signal in advance to suppress high-frequency angular jitter caused by UAV maneuvering and improve the dynamic stability of the system. Kd This is the differential gain coefficient.

[0047] S334. Drive the pan-tilt servo motor to move according to the drive control signal until the comprehensive control deviation converges to within the preset threshold, and output calibration information of the test antenna main lobe line of sight locking the phase center of the ground-based radar under test.

[0048] To further explain, the drive control signal, amplified by the servo driver into motor drive current, drives the rotors of the pitch and yaw axis motors to rotate, which in turn drives the test antenna to change its pointing angle via a mechanical transmission chain. During this process, the encoder continuously provides real-time feedback on the current motor rotation angle. When the absolute value of the overall control deviation remains below a preset threshold, such as 0.05°, it is determined that the line of sight has successfully locked onto the phase center of the ground-based radar under test. At this point, calibration information is output regarding the lock onto the phase center of the ground-based radar using the test antenna's main lobe. This calibration information includes a lock status flag, the current lock deviation value, the lock time, and the corresponding spatial coordinate data.

[0049] S400: Based on the instantaneous roll angle in the instantaneous three-dimensional attitude angle, control the test antenna to perform a reverse rotation with equal amplitude to compensate for the dynamic parallelism between the polarization surface of the test antenna and the preset polarization reference surface.

[0050] In this embodiment, when the UAV rolls due to airflow disturbances, the polarization vector of the test antenna tilts synchronously with the aircraft, causing the originally pure horizontally polarized electromagnetic waves to leak into the vertically polarized channel, severely compromising the accuracy of the cross-polarization isolation measurement. Therefore, this embodiment employs a constant-amplitude reverse rotation strategy based on real-time inversion of the roll angle to cancel out the physical tilt caused by the UAV's body tilt on the polarization surface of the test antenna in real time, ensuring that the polarization surface of the test antenna remains absolutely parallel to the preset polarization reference plane in inertial space. Meanwhile, in this embodiment, the line-of-sight locking control and polarization dynamic compensation of the test antenna are set as two decoupled orthogonal control degrees of freedom. This decomposes the line-of-sight pointing control and polarization attitude control into two independent control channels in three-dimensional space. The line-of-sight locking control uses the spatial position of the phase center of the radar under test as the control target, and achieves real-time alignment of the main lobe line of sight through the pitch and yaw axes. The polarization dynamic compensation uses the spatial normal of the preset polarization reference plane as the control target, and achieves absolute leveling of the polarization vector through the roll axis. Thus, the servo motion of the pitch and yaw axes does not affect the polarization attitude maintained by the roll axis, and the reverse servo rotation of the roll axis does not affect the spatial pointing of the main lobe line of sight. This fundamentally avoids the control accuracy loss caused by multi-axis coupling and realizes the parallel and independent execution of line-of-sight locking and polarization compensation. Specifically, refer to Figure 6 As shown, step S400 may include the following sub-steps S410 to S430: S410. Extract the instantaneous roll angle and roll angle change rate at the current moment from the instantaneous three-dimensional attitude angle.

[0051] S420: The instantaneous roll angle is inverted and used as the roll compensation control quantity to drive the roll axis motor of the gimbal where the test antenna is located to perform reverse servo control in order to compensate for the dynamic parallelism between the polarization surface and the polarization reference surface of the test antenna.

[0052] S430. When the instantaneous roll angle rate exceeds the preset angular rate threshold, Kalman filtering is used to predict the roll angle change at the next moment based on the instantaneous roll angle and the roll angle change rate.

[0053] Furthermore, using only step S420 for real-time reverse rotation can meet the accuracy requirements for maintaining the polarization surface when the roll angle changes relatively slowly. However, when the UAV encounters sudden disturbances such as gusts and the roll rate increases sharply, there is an inherent execution delay between the servo system detecting the roll angle change and completing the reverse compensation. This delay will cause an instantaneous dynamic deviation of the compensated polarization surface relative to the preset reference surface. To address this, a predictive compensation mechanism is introduced in this step to eliminate the residual polarization surface deviation introduced by servo hysteresis. Specifically, an angular rate threshold is first preset. When the instantaneous roll rate exceeds this threshold, the predictive compensation mode is triggered. That is, the extracted instantaneous roll angle and its rate of change at the current moment are used as state observations, and the Kalman filter algorithm is used to optimally estimate the roll angle change at the next moment.

[0054] S440. Based on the change in roll angle and the instantaneous roll angle at the current moment, generate a lead compensation control quantity to drive a pre-compensation rotation before the instantaneous roll angle is generated.

[0055] Furthermore, based on the roll angle change Δ predicted in step S430, the next moment is... Roll ( t +1), combined with the instantaneous roll angle at the current moment. Roll u ( t Generate advance compensation control quantity Roll cmd The advance compensation control quantity is sent to the roll axis motor driver before the actual change in the instantaneous roll angle occurs, driving the gimbal roll axis to perform pre-compensation rotation in advance. This embodiment, through this predictive advance compensation mechanism, upgrades the traditional reactive control to feedforward control, effectively eliminating the residual polarization surface deviation introduced by the inherent execution delay in the servo drive and mechanical transmission links, ensuring that the dynamic parallelism between the polarization surface and the preset reference surface remains within the allowable error range under high-speed maneuvering flight conditions. The calculation formula for the advance compensation control quantity is: Roll cmd =-[ Roll u ( t )+Δ Roll ( t +1)).

[0056] In this embodiment, because the UAV may encounter sudden strong gusts or extreme weather conditions during maneuvering flight, causing drastic changes in its attitude, the steering compensation control quantity may exceed the physical limits of the gimbal actuator where the test antenna is located. If the gimbal continues to be driven according to theoretical calculations, it may lead to actuator saturation or even mechanical damage. Simultaneously, when the instantaneous roll angle exceeds the UAV's own safe flight limit, the UAV may already be in an unstable state. Continuing to perform dynamic polarization compensation at this point is not only meaningless but may also exacerbate fuselage oscillations due to the violent servo movements of the gimbal's roll axis. Therefore, this embodiment introduces a monitoring and safety protection mechanism to monitor key control quantities and attitude states in real time, and to implement protective measures such as amplitude limiting, alarm output, and compensation suspension under abnormal conditions to ensure the operational safety and data validity of the UAV test platform throughout its entire flight envelope. Specifically, refer to... Figure 7 As shown, it also includes the following steps S510 to S530: S510, real-time monitoring of steering compensation control amount and instantaneous roll angle.

[0057] S520. When the steering compensation control amount exceeds the execution range of the test antenna, the steering of the test antenna is limited and the over-limit event is recorded.

[0058] S530: When the instantaneous roll angle exceeds the preset safety threshold, the drone is determined to be in an unstable state, and an alarm signal to suspend dynamic compensation of the polarization surface is output.

[0059] Furthermore, this embodiment also provides a test antenna polarization dynamic compensation and line-of-sight locking system under maneuvering flight conditions, including: The perception module is used to acquire the instantaneous three-dimensional attitude angles and instantaneous three-dimensional spatial coordinates of the UAV; The spatial pointing calculation module is used to calculate the theoretical spatial pointing angle of the test antenna relative to the phase center of the ground-based radar under test based on the absolute spatial coordinates and instantaneous three-dimensional spatial coordinates of the ground-based radar under test. The line-of-sight locking module is used to perform differential control processing on the instantaneous three-dimensional attitude angle and the theoretical spatial pointing angle under the same geodetic reference, and control the main lobe line of sight of the test antenna to lock the phase center of the ground-based radar under test based on the obtained steering compensation control quantity. The polarization surface dynamic compensation module is used to control the test antenna to perform a counter-rotation with equal amplitude based on the instantaneous roll angle in the instantaneous three-dimensional attitude angle, so as to compensate for the dynamic parallelism between the polarization surface of the test antenna and the preset polarization reference surface; wherein, the line-of-sight locking control and the polarization surface dynamic compensation of the test antenna are set as two mutually decoupled orthogonal control degrees of freedom.

[0060] Furthermore, this embodiment also provides an electronic device, including: at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, the instructions being executed by the at least one processor to enable the at least one processor to perform the above-described method for dynamic compensation of test antenna polarization surface and line-of-sight locking under maneuvering flight conditions.

[0061] Finally, this embodiment also provides a computer-readable storage medium storing computer-executable instructions, which, when executed by a processor, implement the above-described method for dynamic compensation of the polarization surface and line-of-sight locking of a test antenna under maneuvering flight conditions.

[0062] In summary, the present invention provides a method, system, device, and medium for dynamic compensation of the polarization surface and line-of-sight locking of a test antenna under maneuvering flight conditions. By assigning two independent electromagnetic measurement physical meanings—spatial line-of-sight locking and polarization surface inverse compensation—to the pitch / yaw and roll axes of a three-axis stabilization gimbal, respectively, the two control channels form orthogonally decoupled degrees of freedom in three-dimensional space. The servo motion of the pitch / yaw axis does not change the polarization surface attitude maintained by the roll axis, and the inverse servo rotation of the roll axis does not affect the spatial pointing of the main lobe line-of-sight. Specifically, this is reflected in the following three aspects: Regarding line-of-sight locking, this embodiment of the invention performs differential control processing on the instantaneous three-dimensional attitude angle and the theoretical spatial pointing angle under the same geodetic reference, and combines a control strategy that weights and fuses the feedforward deviation control quantity and the phase difference feedback correction quantity, as well as a dual closed-loop composite control architecture composed of encoder feedback. This achieves comprehensive compensation for UAV body attitude disturbances and gimbal mechanical errors, ensuring that the main lobe line of sight of the test antenna locks the phase center of the ground-based radar under test in real time with high precision under maneuvering flight conditions.

[0063] Regarding dynamic compensation of the polarization surface, this embodiment of the invention extracts the instantaneous roll angle and performs equal-amplitude reverse rotation, directly cutting off the leakage path of the main polarization component to the orthogonal polarization channel caused by the fuselage tilt from the physical level of the radio frequency front end. At the same time, a Kalman filter prediction algorithm is introduced to achieve advance pre-compensation, effectively eliminating the residual polarization surface deviation introduced by servo hysteresis.

[0064] In terms of safety protection, this embodiment of the invention monitors the steering compensation control amount and instantaneous roll angle in real time, performs amplitude limiting processing and records the over-limit event when the control amount exceeds the limit, and outputs a pause compensation alarm when the roll angle exceeds the safety threshold, thus ensuring the operational safety and data validity of the system throughout the entire flight envelope.

[0065] Therefore, compared with existing technologies that rigidly fix the measurement probe to the fuselage or use only simple damping vibration reduction, as well as those that rely on post-processing digital signal processing for polarization correction, the embodiments of the present invention directly ensure metrological-grade accuracy of antenna pattern, absolute gain, and cross-polarization isolation measurements at the front-end physical layer without the need for complex post-processing digital polarization reconstruction. This significantly reduces dynamic amplitude ripple and polarization crosstalk caused by wind field disturbances, and effectively solves the technical problems of polarization crosstalk and line-of-sight deviation caused by UAV fuselage attitude disturbances.

[0066] Since the systems / devices described in the above embodiments of the present invention are systems / devices used to implement the methods of the above embodiments of the present invention, those skilled in the art can understand the specific structure and modifications of the systems / devices based on the methods described in the above embodiments of the present invention, and therefore will not be described again here. All systems / devices used in the methods of the above embodiments of the present invention fall within the scope of protection of the present invention.

[0067] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0068] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, as well as combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions.

[0069] It should be noted that in the description of this invention, the word "a" or "an" preceding a component does not exclude the existence of multiple such components. This invention can be implemented by means of hardware comprising several different components and by means of a suitably programmed computer. The use of terms such as first, second, third, etc., is merely for convenience and does not indicate any order. These terms can be understood as part of the component names.

[0070] Furthermore, it should be noted that in the description of this specification, the terms "one embodiment," "some embodiments," "embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Furthermore, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0071] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning of the basic inventive concept, can make other changes and modifications to these embodiments.

[0072] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from the spirit and scope of the invention.

Claims

1. A method for dynamic compensation of the polarization surface and line-of-sight locking of a test antenna under maneuvering flight conditions, characterized in that, The method is applied to a UAV test platform equipped with a test antenna, and the method includes: Obtain the instantaneous three-dimensional attitude angles and instantaneous three-dimensional spatial coordinates of the UAV; Based on the absolute spatial coordinates and instantaneous three-dimensional spatial coordinates of the ground-based radar under test, the theoretical spatial pointing angle of the test antenna relative to the phase center of the ground-based radar under test is calculated. Under the same geodetic reference datum, the instantaneous three-dimensional attitude angle and the theoretical spatial pointing angle are differentially controlled, and based on the obtained steering compensation control quantity, the main lobe line of sight of the test antenna is controlled to lock the phase center of the ground-based radar under test. Based on the instantaneous roll angle in the instantaneous three-dimensional attitude angle, the test antenna is controlled to perform a reverse rotation with equal amplitude to compensate for the dynamic parallelism between the polarization surface of the test antenna and the preset polarization reference surface. The line-of-sight locking control and polarization dynamic compensation of the test antenna are set as two decoupled orthogonal control degrees of freedom.

2. The method for dynamic compensation of the polarization surface and line-of-sight locking of a test antenna under maneuvering flight conditions as described in claim 1, characterized in that, Obtaining the instantaneous 3D attitude angles and instantaneous 3D spatial coordinates of the UAV includes: During the UAV flight test, the onboard RTK positioning system and inertial measurement unit are used to simultaneously acquire the UAV's instantaneous three-dimensional spatial coordinates and instantaneous three-dimensional attitude angles, including roll angle, pitch angle and heading angle. Among them, the instantaneous three-dimensional spatial coordinates and instantaneous three-dimensional attitude angles are aligned with hardware timestamps using a unified PPS second pulse signal during acquisition.

3. The method for dynamic compensation of the polarization surface and line-of-sight locking of a test antenna under maneuvering flight conditions as described in claim 1, characterized in that, Based on the absolute spatial coordinates and instantaneous three-dimensional spatial coordinates of the ground-based radar under test, the theoretical spatial pointing angle of the test antenna relative to the phase center of the ground-based radar under test is calculated, including: A local ENU coordinate system is established with the phase center of the ground-based radar under test as the origin. The instantaneous three-dimensional spatial coordinates are converted into relative position vectors in the local ENU coordinate system. The relative position vectors contain position components in three orthogonal directions. The horizontal projection distance is obtained from the horizontal projection component of the relative position vector. Based on the vertical component of the relative position vector and the horizontal projection distance, the theoretical pitch pointing angle of the test antenna relative to the phase center of the ground-based radar under test is calculated. Based on the two horizontal components of the relative position vector, the theoretical azimuth pointing angle of the test antenna relative to the phase center of the ground-based radar under test is calculated. The instantaneous three-dimensional attitude angles are transformed from the body coordinate system to the local ENU coordinate system using a coordinate rotation matrix.

4. The method for dynamic compensation of the polarization surface and line-of-sight locking of a test antenna under maneuvering flight conditions as described in claim 1, characterized in that, Under the same geodetic reference datum, differential control processing is performed on the instantaneous three-dimensional attitude angle and the theoretical spatial pointing angle. Based on the obtained steering compensation control quantity, the main lobe line of sight of the test antenna is locked to the phase center of the ground-based radar under test, including: Based on the real-time differential results between the instantaneous three-dimensional attitude angle of the UAV and the theoretical spatial pointing angle of the test antenna, a feedforward bias control quantity is generated. Based on the real-time phase difference measurement values ​​between the received signals of the same pulse signal from each channel of the array antenna, a feedback correction control quantity is generated, and the feedback correction control quantity is weighted and fused with the feedforward deviation control quantity to obtain the steering compensation control quantity of the test antenna. The steering compensation control quantity is used as the target driving command. After being calculated by the PID control algorithm, it drives the gimbal where the test antenna is located to perform servo motion so that the main lobe line of sight of the test antenna locks the phase center of the ground-based radar under test. Among them, the feedforward deviation control quantity is used to compensate for the spatial pointing deviation of the test antenna caused by the attitude disturbance of the UAV body, and the feedback correction control quantity is used to compensate for the residual pointing error of the main lobe line of the test antenna due to the mechanical error of the gimbal or the residual wind disturbance.

5. The method for dynamic compensation of the polarization surface and line-of-sight locking of a test antenna under maneuvering flight conditions as described in claim 4, characterized in that, The steering compensation control quantity is used as the target driving command, and after being calculated by the PID control algorithm, it drives the gimbal where the test antenna is located to perform servo motion, so that the main lobe line of sight of the test antenna locks the phase center of the ground-based radar under test, including: Obtain the current motor rotation angle in real time from the internal encoders of the pitch axis motor and yaw axis motor of the gimbal; Using the theoretical spatial pointing angle as the target value of closed-loop control and the current motor rotation angle as the feedback value of closed-loop control, deviation calculation is performed to obtain the pointing angle deviation. The steering compensation control quantity is added to the pointing angle deviation as a feedforward term, and the generated comprehensive control deviation is then subjected to PID calculation to generate the drive control signals for the pitch axis motor and the yaw axis motor. The gimbal servo motor is driven by the drive control signal until the overall control deviation converges to within the preset threshold, and the calibration information of the test antenna main lobe line of sight locking the phase center of the ground-based radar under test is output.

6. The method for dynamic compensation of the polarization surface and line-of-sight locking of a test antenna under maneuvering flight conditions as described in claim 1, characterized in that, Based on the instantaneous roll angle in the instantaneous three-dimensional attitude angle, the test antenna is controlled to perform a counter-rotation with equal amplitude to compensate for the dynamic parallelism between the polarization surface of the test antenna and the preset polarization reference surface, including: Extract the instantaneous roll angle and roll rate of change at the current moment from the instantaneous three-dimensional attitude angles; The instantaneous roll angle is inverted and used as the roll compensation control quantity to drive the roll axis motor of the gimbal where the test antenna is located to perform reverse servo control in order to compensate for the dynamic parallelism between the polarization surface and the polarization reference surface of the test antenna. When the instantaneous roll angle rate exceeds the preset angular rate threshold, Kalman filtering is used to predict the roll angle change at the next moment based on the instantaneous roll angle and the roll angle change rate. Based on the change in roll angle and the instantaneous roll angle at the current moment, a lead compensation control quantity is generated to drive a pre-compensation rotation before the instantaneous roll angle is generated.

7. The method for dynamic compensation of the polarization surface and line-of-sight locking of a test antenna under maneuvering flight conditions as described in claim 1, characterized in that, Also includes: Real-time monitoring of steering compensation control quantity and instantaneous roll angle; When the steering compensation control value exceeds the execution range of the test antenna, the steering of the test antenna is limited and the over-limit event is recorded. When the instantaneous roll angle exceeds the preset safety threshold, the drone is determined to be in an unstable state, and an alarm signal to suspend dynamic compensation of the polarization surface is output.

8. A test antenna polarization dynamic compensation and line-of-sight locking system under maneuvering flight conditions, characterized in that, include: The perception module is used to acquire the instantaneous three-dimensional attitude angles and instantaneous three-dimensional spatial coordinates of the UAV; The spatial pointing calculation module is used to calculate the theoretical spatial pointing angle of the test antenna relative to the phase center of the ground-based radar under test based on the absolute spatial coordinates and instantaneous three-dimensional spatial coordinates of the ground-based radar under test. The line-of-sight locking module is used to perform differential control processing on the instantaneous three-dimensional attitude angle and the theoretical spatial pointing angle under the same geodetic reference, and control the main lobe line of sight of the test antenna to lock the phase center of the ground-based radar under test based on the obtained steering compensation control quantity. The polarization surface dynamic compensation module is used to control the test antenna to perform a counter-rotation with equal amplitude based on the instantaneous roll angle in the instantaneous three-dimensional attitude angle, so as to compensate for the dynamic parallelism between the polarization surface of the test antenna and the preset polarization reference surface; wherein, the line-of-sight locking control and the polarization surface dynamic compensation of the test antenna are set as two mutually decoupled orthogonal control degrees of freedom.

9. An electronic device, characterized in that, include: At least one processor; and memory that is communicatively connected to at least one processor; The memory stores instructions that can be executed by at least one processor, which are executed by at least one processor to enable the at least one processor to perform a test antenna polarization dynamic compensation and line-of-sight locking method under maneuvering flight conditions as described in any one of claims 1-7.

10. A computer-readable storage medium storing computer-executable instructions thereon, characterized in that, When the computer-executable instructions are executed by the processor, they implement the method for dynamic compensation of the polarization surface and line-of-sight locking of a test antenna under maneuvering flight conditions as described in any one of claims 1-7.

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