A high-speed full-gyro millimeter wave phased array radar system pointing fast calibration method

Abstract

A kind of full strapdown millimeter wave phased array radar system pointing calibration method, main steps include: to be calibrated system is installed on three-axis turntable, based on the set calibration range and calibration granularity, calculate t time antenna azimuth beam pointing angle and elevation beam pointing angle theoretical value, and corresponding turntable attitude angle theoretical value, control turntable turns to the angle;Adjust phased array antenna beam pointing, so that target is located in the antenna beam center, obtain the actual value of antenna azimuth beam pointing angle and elevation beam pointing angle at this time, with the difference between the beam pointing theoretical value and actual value as the pointing error of phased array at the angle, to complete the calibration test of all angles in calibration range.This is a kind of high-efficiency calibration test method at system level, without accurately determining the coordinate position of each array element of antenna, can take into account the influence of system each link error on beam pointing precision, realize the fast, high-precision high-speed full strapdown millimeter wave phased array test calibration.

Description

Technical Field

[0001] This invention relates to the field of millimeter-wave phased array radar system testing technology, and in particular to a rapid pointing calibration method for a high-speed, fully strapdown millimeter-wave phased array radar system. Background Technology

[0002] Phased array radar antennas do not need to overcome the adverse factors such as scanning inertia and damping of scanning motion systems of mechanical scanning antennas. They have capabilities that conventional radars do not possess, such as fast scanning speed and fast beamforming. They are highly flexible and widely used in fields such as early warning, guidance, fire control and beyond-line-of-sight detection.

[0003] During guidance, the beam pointing angle of the antenna depends on the relative position of the missile and the missile's attitude. For a typical platform-type radar system, the relative position of the missile and the missile's attitude are slow-changing variables over time. Therefore, the beam pointing angle of a platform-type radar system is also a slow-changing variable over time, with a small change in amplitude over a short period, resulting in a small fluctuation in pointing error. Unlike platform-type radar systems, high-speed full-stripper phased array radar systems employ a full-stripper guidance system, with the phased array radar system directly fixed to the missile body. Under high-speed conditions, the phased array antenna rotates coaxially with the missile axis, and the beam pointing of the phased array antenna changes periodically and rapidly with the rotation of the missile axis. Over a short period, the beam pointing of the phased array antenna is a periodic sinusoidal component with the same frequency as the rotation speed. The accuracy of the phased array antenna varies with different pointing angles; the larger the pointing angle, the worse the accuracy. Under roll conditions, the beam pointing of the phased array antenna oscillates sinusoidally between peaks and troughs, resulting in a larger fluctuation range in pointing error. In high-speed, all-stripper guidance systems, the missile control system decouples the missile's roll based on the beam pointing of the phased array antenna and the missile's attitude to extract the line-of-sight angular velocity for missile maneuver control. Under high-speed conditions, the pointing accuracy of the phased array antenna fluctuates significantly, and the pointing error is coupled with the roll rate. These two factors directly affect the accuracy of the line-of-sight angular velocity estimation, further impacting the hit accuracy. Therefore, beam pointing accuracy is not only a crucial technical indicator for phased array antennas, but the requirements for beam pointing accuracy are even higher in the field of all-stripper tracking guidance.

[0004] Numerous factors influence the pointing accuracy of a full-stripper phased array radar system, making it difficult to determine through theoretical analysis alone. One source of pointing error in a phased array antenna is the antenna itself. Inconsistencies in components such as power dividers, phase shifters, and cable connectors during manufacturing and installation, as well as structural variations like deformation and asymmetry of the antenna array, cause phase changes and lead to pointing errors. Simultaneously, quantization errors in phase shifters, inter-element coupling, and pattern distortion at large angles also directly affect pointing accuracy. Furthermore, another portion of pointing error originates from system-level assembly of the phased array antenna with the radar system processor and the missile body. Inconsistencies in components such as RF cables and phase changes caused by the parallelism between the array surface and the missile body affect the pointing accuracy of the phased array antenna.

[0005] Existing phased array calibration methods mainly fall into two categories: planar near-field and microwave anechoic chamber far-field. Planar near-field scanning requires scanning each channel sequentially, which is extremely labor-intensive, cannot be performed in parallel, and is very time-consuming. Microwave anechoic chamber far-field scanning requires small-range scanning at each pointing angle, calibrating at N angles in a two-dimensional spatial domain. This necessitates N*N small-range scans in both dimensions, resulting in a massive workload and significant time consumption. Summary of the Invention

[0006] This disclosure provides a rapid pointing calibration method for a high-speed, all-stripper millimeter-wave phased array radar system. The method uses the phased array radar system for system-level overall calibration, taking into account pointing errors arising from the phased array antenna itself and those generated during the assembly of the phased array with other sub-units. This method employs a closed-loop system tracking approach, performing only one scan at each pointing angle. Beam pointing is corrected by angular deviation, effectively reducing calibration workload and achieving efficient, rapid, and high-precision testing and calibration. This meets the beam pointing accuracy requirements of phased array antennas in the field of all-stripper tracking and guidance under high-speed conditions.

[0007] To achieve the above objectives, the pointing calibration method for a high-speed, fully strapdown millimeter-wave phased array system provided in this disclosure mainly includes the following steps:

[0008] Install the radar system to be calibrated onto the test fixture;

[0009] Measure the roll-off parallelism Δr of the antenna array relative to the standard plane at the bottom of the fixture;

[0010] The test fixture and radar system were mounted on a three-axis turntable, and the roll angle of the turntable was adjusted to -Δr; the two-dimensional calibration range and calibration granularity were set, including azimuth and pitch directions.

[0011] Adjust the turntable so that both the target simulation system and the radar system are in electromagnetic null position; calculate the spatial relationship between the antenna coordinate system and the turntable coordinate system;

[0012] Based on the set calibration range and calibration granularity, the theoretical value of the antenna azimuth beam pointing angle at time t is calculated. Theoretical value of pitch beam pointing angle And by using the relationship between the antenna coordinate system and the turntable coordinate system, the corresponding theoretical value of the turntable attitude angle is calculated;

[0013] The control turntable drives the radar system to the position of the turntable's theoretical attitude angle.

[0014] Based on the angle measurement results of the phased array radar system, the phased array antenna beam pointing is adjusted so that the target is located at the center of the antenna beam. At this time, the actual value of the antenna azimuth beam pointing angle is... Actual value of pitch beam pointing angle

[0015] Based on the theoretical and actual values ​​of the beam pointing angle, the azimuth error at this time is obtained. Pitch angle error

[0016] like If the accuracy μ is satisfied, then the actual pointing of the phased array can be calculated. Pointing error

[0017]

[0018] Repeat the above steps according to the set calibration range until the calibration test of all angles within the calibration range is completed with the set granularity.

[0019] Furthermore, the roll-off parallelism Δr of the phased array antenna surface relative to the standard plane at the bottom of the fixture is measured using a coordinate measuring machine. Specific methods include:

[0020] Place the radar system to be calibrated and the tooling flat on the coordinate measuring machine. Take three points on the side of the antenna array to form plane 1, and take three points on the tooling platform to form plane 2. Measure the parallelism between plane 1 and plane 2, that is, the roll-off parallelism of the phased array antenna array relative to the standard ground.

[0021] Further steps for calculating the theoretical values ​​of the beam pointing angle and the turntable pointing angle specifically include:

[0022] S6.1 Within the azimuth calibration range Φ and the elevation calibration range θ, obtain the theoretical value of the azimuth beam pointing angle of the phased array antenna at time t using the azimuth calibration granularity ΔΦ and the elevation calibration granularity Δθ. Theoretical value of pitch beam pointing angle

[0023]

[0024]

[0025] S6.2, utilizing the spatial relationship between the antenna coordinate system and the three-axis turntable coordinate system:

[0026]

[0027] The theoretical values ​​of the turntable attitude angles, including the yaw angle, were calculated. t Pitch t :

[0028]

[0029]

[0030] Where o1, o2, and o3 represent the direction cosines of the X-axis of the phased array antenna coordinate system and the X, Y, and Z axes of the three-axis turntable mechanical coordinate system, respectively;

[0031] p1, p2, and p3 represent the direction cosines of the Y-axis of the phased array antenna coordinate system and the X, Y, and Z axes of the three-axis turntable mechanical coordinate system, respectively.

[0032] q1, q2, and q3 represent the direction cosines of the Z-axis of the phased array antenna coordinate system and the X, Y, and Z-axis of the three-axis turntable mechanical coordinate system, respectively.

[0033] Furthermore, the step of adjusting the antenna beam pointing angle specifically includes:

[0034] Calculated by the all-slip millimeter-wave phased array radar system: Turntable attitude angle yaw t Pitch t Under the given position, so that the target is located at the center of the phased array antenna beam, that is, when the angle measurement results of the phased array radar system, i.e., the azimuth and elevation angle errors, are 0°, the actual value of the azimuth beam pointing angle of the phased array antenna. Actual value of pitch beam pointing angle It is then sent to the phased array antenna in the all-slippery millimeter-wave phased array radar system for execution.

[0035] Furthermore, the actual value of the azimuth beam pointing angle of the phased array antenna. Actual value of pitch beam pointing angle The specific calculation methods include:

[0036] First, based on the actual value of the beam pointing angle of the phased array antenna at the previous moment... and And the elevation angle error measurement obtained by the all-slip-coupled millimeter-wave phased array radar system Azimuth error measurement value Calculate beam azimuth and elevation scanning angular velocity

[0037]

[0038] Beam scanning angular velocity By integrating and performing appropriate signal processing, the actual value of the azimuth beam pointing angle of the phased array antenna is obtained when the target is located at the center of the phased array antenna beam at the next moment. Actual value of pitch beam pointing angle

[0039]

[0040] Compared with the prior art, the beneficial effects of this disclosure are: (1) It does not require the use of high-precision instruments to determine the coordinate position of each element of the phased array antenna, but corrects the beam pointing by angular deviation, and only performs one scan at each pointing angle, which can effectively reduce the calibration workload; (2) This is a system-level calibration and testing method that can take into account the influence of manufacturing errors, quantization errors of the phase shifter, mutual coupling of elements, antenna array structure such as deformation and asymmetry, and pointing errors caused by pattern distortion under large angle conditions on the beam pointing accuracy of the phased array in high-speed full-stripper millimeter-wave phased array systems; (3) It can achieve efficient and fast high-precision testing and calibration, and meet the requirements of high-speed tracking and guidance field for the pointing accuracy of phased arrays. Attached Figure Description

[0041] The above and other objects, features and advantages of this disclosure will become more apparent from the more detailed description of exemplary embodiments of this disclosure taken in conjunction with the accompanying drawings, in which the same reference numerals generally represent the same components.

[0042] Figure 1 This is an exemplary calibration system structure diagram applied to the calibration method described in this disclosure;

[0043] Figure 2 A flowchart illustrating an exemplary embodiment of this disclosure;

[0044] Figure 3 For an azimuth beam pointing angle within the range of [-Φ, Φ], and a pitch beam pointing angle of M°, the theoretical attitude angle yaw of the three-axis turntable system is... t and pitch t The changing trend. Detailed Implementation

[0045] Preferred embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While preferred embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may 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 disclosure will be thorough and complete, and will fully convey the scope of the present disclosure to those skilled in the art.

[0046] This disclosure provides a pointing calibration method for a high-speed, fully strapdown millimeter-wave phased array radar. In one exemplary embodiment, the calibration device used in this method is shown in the attached diagram. Figure 1 As shown, it mainly includes:

[0047] Main control computer 1;

[0048] A three-axis turntable system 2 is mounted on which a fully strapdown millimeter-wave phased array radar system 4 to be calibrated is installed. It is connected to a main control computer 1, and the main control computer 1 controls the three-axis turntable system 2 to move the fully strapdown millimeter-wave phased array radar system 4 to be calibrated to the attitude to be calibrated.

[0049] The target simulation system 5 includes a target signal source, a standard horn, and a radio frequency cable. The target signal generated by the target signal source is radiated through the standard horn to the full-strap-coupled millimeter-wave phased array radar system 4 to be calibrated.

[0050] The information acquisition system 3 is connected to the main control computer 1. It records the attitude angle information fed back by the three-axis turntable system 2, the angle error measurement information fed back by the full-stripper millimeter-wave phased array radar system 4 to be calibrated, and the beam pointing angle information, and transmits them to the main control computer 1 for data storage and processing.

[0051] The all-stripper millimeter-wave phased array radar system 4 to be calibrated includes a phased array antenna, a signal processing system, and a beam control system. The phased array antenna contains a temperature sensor to monitor the component temperature in real time. The signal processing system obtains the angular error measurement result based on the target echo signal fed back by the phased array antenna and sends the result to the beam control system. The beam control system obtains the beam command that will center the target in the beam at the next moment. The phased array antenna receives and executes the beam command calculated by the beam control system and feeds back the real-time operating temperature of the phased array antenna to the signal processing system.

[0052] The pointing calibration method for a high-speed, fully strapdown millimeter-wave phased array system based on the above-mentioned equipment specifically includes the following steps:

[0053] Step 1: Initialize and configure the microwave anechoic chamber testing environment, and configure the required testing instruments and equipment.

[0054] Step 2: Use a coordinate measuring machine to measure the roll-off parallelism Δr of the millimeter-wave phased array antenna array surface in the phased array radar system 4 to be calibrated relative to the standard plane at the bottom of the fixture, and record it.

[0055] Step 3: Install the phased array radar system 4 to be calibrated on the three-axis turntable system 2. Under the control of the main control computer 1, perform initial position positioning settings for the three-axis turntable system 2 and the full strapdown millimeter-wave phased array radar system 4, and adjust the roll angle of the three-axis turntable system 2 to -Δr.

[0056] Step 4: Set the two-dimensional airspace calibration range and calibration granularity, including the azimuth calibration range Φ, the azimuth calibration granularity ΔΦ, the pitch calibration range θ, and the pitch calibration granularity Δθ.

[0057] Step 5: Adjust the three-axis turntable system 2 so that both the target simulation system 5 and the full-slip-line millimeter-wave phased array radar system 4 to be calibrated are in electromagnetic zero position, that is, the azimuth and elevation beam pointing angle of the phased array antenna in the full-slip-line millimeter-wave phased array radar system 4 to be calibrated are 0°, and the azimuth and elevation angle error measurement values ​​obtained by the signal processing system in the full-slip-line millimeter-wave phased array radar system 4 to be calibrated are 0°.

[0058] Step 6: Based on the calibration range and calibration granularity set in the above steps, the main control computer 1 calculates the theoretical value of the azimuth beam pointing angle of the phased array antenna at time t. Theoretical value of pitch beam pointing angle And through the spatial coordinate relationship between the antenna coordinate system and the turntable coordinate system Calculate the theoretical values ​​of the turntable attitude angles, including the yaw angle. t Pitch t .

[0059] For example, when the pitch pointing angle is fixed at M°, and the azimuth varies within the range of the beam pointing angle [-Φ, Φ], the theoretical value of the turntable attitude angle is yaw. t and pitch t Calculate according to the following formula:

[0060]

[0061]

[0062] Appendix Figure 3 The theoretical attitude angle (yaw) of the three-axis turntable system 2 is given when the pitch beam pointing angle is M° within the azimuth beam pointing angle range of [-Φ, Φ]. t and pitch t The changing trend.

[0063] Where [M,N] represents the yaw angle of the three-axis rotary table system 2.t The range [P,Q] represents the pitch angle of the three-axis rotary table system 2. t The range of values ​​is obtained by calculation using the above formula.

[0064] Step 7: The main control computer 1 controls the three-axis turntable system 2 to move the full-slip-coupled millimeter-wave phased array radar system to be calibrated to the turntable attitude angle yaw calculated in step 4 above. t Pitch t Location.

[0065] Step 8: Calculate the turntable attitude angle yaw using the all-slip-in-line millimeter-wave phased array radar system 4. t Pitch t The position ensures that the angle measurement results of the phased array radar system 4, namely the azimuth and elevation angle errors, are 0°. That is, when the target is located at the center of the phased array antenna beam, the actual value of the azimuth beam pointing angle of the phased array antenna is... Actual value of pitch beam pointing angle It is then sent to the phased array antenna in the All-Straight-Link millimeter-wave phased array radar system 4 for execution.

[0066] Step 9: The all-straight-through millimeter-wave phased array radar system obtains the actual value of the phased array antenna's azimuth beam pointing angle based on the target echo. Actual value of pitch beam pointing angle At that time, the azimuth error is obtained. Pitch angle error The measured value.

[0067] Step 10: The information acquisition system 3 collects and records the attitude angle information (yaw) of the three-axis turntable system 2 at the same moment. t pitch t Yaw and pitch attitude angular velocity information ω yt ω zt Actual value of phased array antenna beam pointing angle and theoretical value and azimuth error Pitch angle error

[0068] Step 11: Based on the calibration range set in Step 2, the main control computer 1 controls the repeated execution of Steps 4, 5, 6, and 7 until the calibration test of all angles within the two-dimensional spatial calibration range is completed at the set granularity.

[0069] Step 12: Calculate the azimuth error within the calibration range. Pitch angle error When the accuracy condition μ is met, the actual direction of the phased array Pointing error at time

[0070]

[0071]

[0072] The specific process of step 2 is as follows:

[0073] Place the product to be calibrated and the tooling flat on the coordinate measuring machine. Take three points on the side of the antenna array to form plane 1, and take three points on the tooling platform to form plane 2. Measure the parallelism between plane 1 and plane 2, that is, the roll-off parallelism of the phased array antenna array relative to the standard ground.

[0074] The specific process of step 8 is as follows:

[0075] Step 8.1: First, based on the actual value of the beam pointing angle of the phased array antenna at the previous moment... and And the elevation angle error measurement obtained by the all-slip-coupled millimeter-wave phased array radar system Azimuth error measurement value Calculate beam azimuth and elevation scanning angular velocity

[0076]

[0077] Step 8.2: Set the beam scanning angular velocity By integrating and processing the signal accordingly, the actual value of the azimuth beam pointing angle of the phased array antenna when the target is located at the center of the phased array antenna beam at the next moment can be obtained. Actual value of pitch beam pointing angle

[0078]

[0079] The above technical solutions are merely exemplary embodiments of the present invention. For those skilled in the art, based on the application methods and principles disclosed in the present invention, it is easy to make various types of improvements or modifications, and not limited to the methods described in the specific embodiments of the present invention. Therefore, the methods described above are merely preferred and not restrictive.

Claims

1. A pointing calibration method for a fully strapdown millimeter-wave phased array radar system, comprising the following steps: S1. Install the radar system to be calibrated on a three-axis turntable and make the phased array antenna parallel to the ground. S2, set the calibration range and calibration granularity for azimuth and pitch directions; S3, Adjust the turntable so that both the target simulation system and the radar system are in electromagnetic null position; Calculate the spatial relationship between the antenna coordinate system and the turntable coordinate system; S4, based on the set calibration range and calibration granularity, calculates... Theoretical value of antenna azimuth beam pointing angle at any time Theoretical value of pitch beam pointing angle And by using the relationship between the antenna coordinate system and the turntable coordinate system, the corresponding theoretical value of the turntable attitude angle is calculated; S5, control the turntable to move the radar system to the position of the turntable's theoretical attitude angle; S6. Based on the angle measurement results of the phased array radar system, adjust the phased array antenna beam pointing so that the target is located at the center of the antenna beam. At this time, the actual value of the antenna azimuth beam pointing angle is... Actual value of pitch beam pointing angle ; S7, based on the theoretical and actual values ​​of the beam pointing angle, obtain the azimuth error at this time. Pitch angle error ; S8, if , Meet accuracy Then calculate the actual direction of the phased array. , Pointing error at time , : S9. According to the set calibration range, repeat steps S4-S8 until the calibration test of all angles within the calibration range is completed with the set granularity. Step S6 specifically includes: Calculated by the all-slip-in millimeter-wave phased array radar system: Turntable attitude angle Pitch angle Under the given position, so that the target is located at the center of the phased array antenna beam, that is, when the angle measurement results of the phased array radar system, i.e., the azimuth and elevation angle errors, are 0°, the actual value of the azimuth beam pointing angle of the phased array antenna. Actual value of pitch beam pointing angle And it is sent to the phased array antenna in the all-strap-connected millimeter-wave phased array radar system for execution; Among them, the actual value of the azimuth beam pointing angle of the phased array antenna Actual value of pitch beam pointing angle The specific calculation methods include: First, based on the actual value of the beam pointing angle of the phased array antenna at the previous moment... and The elevation angle error measurements obtained from the all-slip-coupled millimeter-wave phased array radar system. Azimuth error measurement value Calculate beam azimuth and elevation scanning angular velocity. , : ； In the formula, For pitch attitude angular velocity information, This refers to yaw attitude angular velocity information; Beam scanning angular velocity , By integrating and performing appropriate signal processing, the actual value of the azimuth beam pointing angle of the phased array antenna is obtained when the target is located at the center of the phased array antenna beam at the next moment. Actual value of pitch beam pointing angle : 。 2. The method according to claim 1, characterized in that, Step S1 specifically includes: S11, Install the radar system to be calibrated onto the test fixture; S12, Measure the roll parallelism of the antenna array relative to the standard plane at the bottom of the fixture. ; S13. Install the test fixture and radar system on the three-axis rotary table, and adjust the roll angle of the rotary table to... .

3. The method according to claim 2, characterized in that, The specific method of step S12 includes: Place the radar system to be calibrated and the fixture flat on the coordinate measuring machine. Take three points on the side of the antenna array to form plane 1, and take three points on the fixture platform to form plane 2. Measure the parallelism between plane 1 and plane 2, that is, the roll-off parallelism of the phased array antenna array relative to the standard plane at the bottom of the fixture.

4. The method according to any one of claims 1-3, characterized in that, Step S4 specifically includes: S4.1, within the azimuth calibration range Pitch calibration range Within the range, azimuth calibration granularity Pitch calibration particle size Obtain the theoretical value of the azimuth beam pointing angle of the phased array antenna at time t. Theoretical value of pitch beam pointing angle : ； S4.2, utilizing the spatial relationship between the antenna coordinate system and the three-axis turntable coordinate system: The theoretical values ​​of the turntable attitude angles, including yaw angle, were calculated. Pitch angle : in, , , These represent the direction cosines of the X-axis of the phased array antenna coordinate system and the X, Y, and Z axes of the three-axis turntable mechanical coordinate system, respectively. , , These represent the direction cosines of the Y-axis of the phased array antenna coordinate system and the X, Y, and Z axes of the three-axis turntable mechanical axis coordinate system, respectively. , , These represent the direction cosines of the Z-axis of the phased array antenna coordinate system and the X, Y, and Z-axis of the three-axis turntable mechanical coordinate system, respectively.

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