A swash plate machine phase scanning radar installation angle self-adaptive correction method

Abstract

The present application relates to airborne fire control radar technical field, disclose a kind of swash plate machine phase scanning radar installation angle self-adapting correction method, respectively obtain the target angle before and after radar array rotation, according to the target angle before and after rotation, respectively calculate the geographic system target angle centroid before and after rotation, and predict the predicted angle of target after rotation;Convert the geographic system target angle centroid to radar system, calculate the installation angle correction value;Real target angle is calculated using the installation angle correction value updated installation angle.The present application can be through the change of target angle in the process of long-distance target tracking with servo angle to deduce servo actual angle deviation, improve target tracking precision by real-time correction this deviation.

Description

Technical Field

[0001] This invention relates to the field of airborne fire control radar technology, specifically to an adaptive correction method for the installation angle of a swashplate phase-scanning radar. Background Technology

[0002] In current air combat, whether engaging the enemy solo or in coordinated engagements, fighter jets face the threat of medium-range missile attacks. This is especially true when the enemy's airborne radar and missile capabilities are comparable, as head-on engagements could give the opponent a "first-look, first-fire" opportunity, putting the fighter at a disadvantage. Without a wide field of view (FVR), fighter jets are forced to maintain a dangerously close distance to enemy aircraft, making them more vulnerable to missile strikes. Therefore, fighter jets require a wide FVR. While mainstream active phased array radars can achieve situational awareness through beam control systems, they have significant limitations when scanning over extremely large areas. Traditional fixed-array active phased array radars have a situational awareness range of only 120° forward-looking cone, limiting their operational scenarios. For fighter jets that cannot install side-looking array radars, wide FVR coverage is primarily achieved through a combination of mechanical and phased-array scanning.

[0003] Fighter fire control radar, through a combination of mechanical and phase scanning, can significantly increase the fighter's field of view. This allows the fighter to immediately make a sharp turn and escape after launching air-to-air missiles, maneuvering into the enemy's main clutter blind zone and disrupting enemy radar tracking. Simultaneously, the fighter is allowed to remain outside the no-escape zone of enemy air-to-air missiles as much as possible, relying on side-pointing radar beams to maintain target tracking and weapon control. This greatly improves the exchange ratio against enemy fighters lacking wide field-of-view coverage, representing a feasible way to enhance combat effectiveness.

[0004] Employing a rotating servo mechanism on the array disk can extend the radar's situational awareness capability to a 180° forward-looking cone angle range. However, during operation, slant-disk phased-array radars suffer from several issues. These include system deviations in the servo positioning mechanism, compensation deviations in the active phased array antenna installation angle, malfunctions in the rotation gear angle sensor, prolonged high-acceleration vibrations of the servo mechanism, and communication delays between the servo and the main control unit. These factors lead to discrepancies between the servo angle returned by the servo device and the actual angle at different antenna array rotation angles. Particularly during target tracking, when the antenna array rotates because the target angle exceeds the current situational awareness range, the target tracking angle error increases significantly. Furthermore, the inconsistent angle errors caused by different antenna array rotation angles reduce the probability of missile hits. Therefore, a real-time adaptive correction scheme is urgently needed to address this problem in the design of slant-disk phased-array radars. Summary of the Invention

[0005] In view of this, the present invention provides an adaptive correction method for the installation angle of a swashplate phase-scanning radar. By inferring the actual servo angle deviation from the target angle during long-range target tracking, the method corrects the deviation in real time to improve target tracking accuracy.

[0006] An adaptive correction method for the installation angle of a swashplate phase-scanning radar includes the following steps:

[0007] Step 1: Obtain the target angles before and after the radar array rotates;

[0008] Step 2: Based on the target angles before and after the rotation, calculate the centroid of the geographic target angles before and after the rotation, and predict the target angle after the rotation.

[0009] Step 3: Convert the target angle centroid from the geographic system to the radar system and calculate the installation angle correction value;

[0010] Step 4: Calculate the true target angle using the updated installation angle correction value.

[0011] Furthermore, in step 1, the swashplate radar array is distinguished as to whether it is rotating based on whether the change between the current servo angle of the swashplate and the servo angle during the last detection exceeds a preset threshold one, and whether the servo rotation angular velocity is less than a preset threshold two.

[0012] Furthermore, in step 2, the centroid is determined based on multiple target angle measurements before and after the rotation. The specific calculation method is as follows:

[0013]

[0014] in, k =1 or 2, The centroid of the target angle in the geographic system before rotation. Let the centroid of the target angle be the one after rotation. , These are the measured values ​​of the target's azimuth and elevation angles before and after rotation. , These are the average values ​​of the corresponding angle measurements before and after rotation. m The number of times the target angle is measured before or after rotation.

[0015] Furthermore, in step 2, the predicted angle of the target after rotation is obtained using a second-order Taylor expansion:

[0016]

[0017]

[0018] in, The target geographic orientation angle. The elevation angle of the target geographic system. t 1 represents the time before the servo of the swashplate phase-scanning radar rotates. t 2 represents the time after rotation; the target angle before rotation. .

[0019] Furthermore, the process of converting the centroid of the target angle from the geographic system to the radar system in step 3 is as follows:

[0020] Transition from Geographical System to Stable System:

[0021]

[0022] in The inertial navigation angle before the array rotates;

[0023] Geography system transformation matrix

[0024] in , , , and Let the inertial navigation climb angle and roll angle be the inertial navigation angles before the array rotates, respectively. Then, the azimuth and pitch angles of the stable system corresponding to the target's centroid are respectively:

[0025] Stable azimuth angle Pitch angle

[0026] Stable system transformation variables:

[0027]

[0028]

[0029] Stable system transformation matrix

[0030] in and Let the forward and elevation installation angles of the array be the forward and elevation angles, respectively. Then, the radar system azimuth and elevation angles corresponding to the target's centroid are as follows:

[0031] Azimuth

[0032] Pitch angle .

[0033] Furthermore, in step 3

[0034] The azimuth installation angle correction value is:

[0035]

[0036] Where Θ is the angle transformation correction value, which takes the value (0, π); The installation angle is the orientation after rotation;

[0037] The pitch installation angle correction value is:

[0038]

[0039] in,

[0040] .

[0041] Furthermore, in step 4, by Installation angle of formula correction Recalculate the target geographic system angle.

[0042] Compared with the prior art, the beneficial effects of the present invention are as follows: the present invention infers the actual servo angle deviation by observing the change of the target angle with the servo angle during the long-distance target tracking process, and improves the target tracking accuracy by correcting the deviation in real time. Attached Figure Description

[0043] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0044] Figure 1 This is a flowchart of the adaptive correction method for the installation angle of the swashplate phase-scanning radar in Example 2;

[0045] Figure 2 This is a schematic diagram showing the change in the target's centroid before and after servo rotation in Example 2;

[0046] Figure 3 The test parameter curves for servo angle, roll angle, climb angle, and heading angle in Example 2 are shown.

[0047] Figure 4 The images show the target track before correction, the target track after correction, and the GPS track map in Example 2. Detailed Implementation

[0048] The embodiments of this application will now be described in detail with reference to the accompanying drawings.

[0049] The following specific examples illustrate the implementation of this application. Those skilled in the art can easily understand other advantages and effects of this application from the content disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. This application can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this application. It should be noted that, in the absence of conflict, the following embodiments and features in the embodiments can be combined with each other. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0050] Example 1

[0051] An adaptive correction method for the installation angle of a swashplate phase-scanning radar includes the following steps:

[0052] Step 1: Obtain the target angles before and after the radar array rotates;

[0053] Step 2: Based on the target angles before and after the rotation, calculate the centroid of the geographic target angles before and after the rotation, and predict the target angle after the rotation.

[0054] Step 3: Convert the target angle centroid from the geographic system to the radar system and calculate the installation angle correction value;

[0055] Step 4: Calculate the true target angle using the updated installation angle correction value.

[0056] In this embodiment, by inferring the actual servo angle deviation by observing the change in target angle with servo angle during long-range target tracking, steps 1-4 can be used repeatedly to correct the target tracking angle deviation caused by servo return error during target tracking by the swashplate phase-scanning radar, thereby improving target tracking accuracy.

[0057] Example 2

[0058] This embodiment further illustrates the present invention through specific implementation examples, related steps, and data.

[0059] A method for adaptive correction of the mounting angle of a swashplate phase-scanning radar, wherein the mounting angle adaptive correction frame is as follows after servo rotation. Figure 1 As shown.

[0060] Step 1: Determine if there are any changes in the swashplate phase-scanning radar servo during the tracking process:

[0061] Specifically, issues such as platform vibration and data transmission accuracy can cause a small range of fluctuations in the servo return angle when the swashplate phase-scanning radar array is not rotating. Under normal circumstances, the change in servo angle is less than 0.1°. Here, we take the servo angle change threshold δ=0.1°.

[0062] If δ≤0.1°, the radar array is considered not to have rotated, and the azimuth installation angle is calculated based on the servo return angle. and pitch installation angle :

[0063]

[0064]

[0065] in, This is the servo angle before rotation.

[0066] When δ > 0.1° and the servo (rotation) speed (Servo speed threshold in this embodiment) If the radar array is considered to have rotated, then the installation angle will be calculated in the following steps:

[0067] Step 2: Calculation and linear prediction of the target angle centroid before and after rotation:

[0068] Specifically, during target tracking by a swashplate phased array radar, the array face adjusts the servo angle according to changes in the target angle under certain conditions. However, due to issues such as system deviations in the servo positioning mechanism, compensation deviations in the installation angle of the active phased array antenna, malfunctions in the rotation gear angle sensor, prolonged high-acceleration vibrations of the servo mechanism, and communication delays between the servo and the main control unit, there can be a certain deviation between the servo angle returned by the servo and the actual servo angle, thus increasing the target tracking angle error. To improve the accuracy of the installation angle error calculation, such as... Figure 2 As shown, the target angle measurements were taken multiple times before rotation. Find the center of mass:

[0069]

[0070] in, k =1 or 2, The centroid of the target angle in the geographic system before rotation. The centroid of the target angle in the geographic system before rotation. , These are the measured values ​​of the target's azimuth and elevation angles, respectively. , , which are the average values ​​of the corresponding angle measurements, and m is the number of times the target angle was measured before or after rotation.

[0071] The radar servo structure (swashplate) resets, and the initial positioning returns an accurate servo angle. During the operation of the radar servo structure (swashplate), the deviation between the positioning return servo angle and the actual angle is less than 0.5°. In a short time (<0.1s), by approximating a linear change in the target angle, the change in the geographic coordinate angle of a target at medium to long distances (≥80km) is ≤0.1°.

[0072] The time before the servo rotates in the swashplate phase-scanning radar is The time after rotation is Target angle before rotation The target geographic azimuth angle predicted by the second Taylor expansion is:

[0073]

[0074] Similarly, by using a second Taylor expansion, the result of extrapolation based on the measurement before rotation can be calculated. .

[0075] Step 3: Convert the centroid of the target measurement angle from the geographic system to the radar system.

[0076] and The conversion process is the same, and the following will be based on... Let's take an example to perform the conversion.

[0077]

[0078] in The formula represents the inertial navigation angle before the array rotates, and it enables the conversion of the angle from the geographic frame to the stable frame.

[0079] Geography system transformation matrix

[0080] in , , , and Let the inertial navigation climb angle and roll angle be the inertial navigation angles before the array rotates, respectively. Then, the azimuth and pitch angles of the stable system corresponding to the target's centroid are respectively:

[0081] Stable azimuth angle Pitch angle

[0082] Stable system transformation variables:

[0083]

[0084]

[0085] Stable system transformation matrix

[0086] in and Let the forward and elevation installation angles of the array be the forward and elevation angles, respectively. Then, the radar system azimuth and elevation angles corresponding to the target's centroid are as follows:

[0087] Azimuth

[0088] Pitch angle

[0089] Step 4: Calculate the installation angle correction value.

[0090] For targets at medium to long distances (≥30km), the change in the geographic coordinate system angle is ≤0.1° within a short time (≤0.5s), indicating that the centroid of the target angle after rotation, after installation angle correction, is approximately equal to the centroid of the target angle before rotation. For ease of calculation and under the condition that the accuracy of the installation angle correction value does not affect the design requirements, it is assumed here that the centroid of the target angle before and after rotation is equal after installation angle correction. Therefore, the following relationship is obtained for any variables x and y:

[0091] Installation angle transformation matrix ,

[0092] in ,

[0093]

[0094] We can obtain:

[0095]

[0096] Where Θ is the angle transformation correction value, which takes the value (0, π).

[0097]

[0098] Therefore, the azimuth installation angle correction value is:

[0099]

[0100] but:

[0101]

[0102] in

[0103]

[0104] Similarly, the pitch installation angle correction value can be obtained as follows:

[0105]

[0106] Step 5: Calculate the true target angle using the updated installation angle:

[0107]

[0108] Finally, the installation angle as modified above Recalculate the target geographic system angle.

[0109] like Figure 3 As shown, the test parameters such as servo angle, roll angle, climb angle, and heading angle are as follows. Based on the above analysis, in the case of... Figure 4 Given the target trajectory angle before correction, the target trajectory angle after correction can be calculated. Experimental results show that the corrected target trajectory angle is closer to the target trajectory angle calculated by GPS, effectively improving trajectory tracking accuracy in complex target environments. This demonstrates the feasibility of the method and fully proves that the method proposed in this patent can adaptively correct servo return angle deviations by improving the angle error compensation algorithm without changing the swashplate phase-scanning radar hardware.

[0110] The above are merely specific embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A swash plate machine phase scanning radar installation angle self-adaptive correction method, characterized in that, Includes the following steps: Step 1: Obtain the target angles before and after the radar array rotates; Step 2: Based on the target angles before and after rotation, calculate the centroid of the geographic target angles before and after rotation, and predict the target's predicted angle after rotation; wherein, the centroid is calculated based on multiple target angle measurements before and after rotation as follows: in, k =1 or 2, The centroid of the target angle in the geographic system before rotation. Let the centroid of the target angle be the one after rotation. , These are the measured values ​​of the target's azimuth and elevation angles before and after rotation. , These are the average values ​​of the corresponding angle measurements before and after rotation. m The number of times the target angle is measured before or after rotation; The predicted angle of the target after rotation is obtained from the second Taylor expansion: in, The target geographic orientation angle. The elevation angle of the target geographic system. t 1 represents the time before the servo of the swashplate phase-scanning radar rotates. t 2 represents the time after rotation; the target angle before rotation. ; Step 3: Convert the target angle centroid from the geographic system to the radar system and calculate the installation angle correction value; Step 4: Calculate the true target angle using the updated installation angle correction value.

2. The adaptive correction method for the installation angle of a swashplate phase-scanning radar according to claim 1, characterized in that, In step 1, the swashplate radar array is distinguished as to whether it is rotating based on whether the change between the current servo angle of the swashplate and the servo angle during the last detection exceeds a preset threshold one, and whether the servo rotation angular velocity is less than a preset threshold two.

3. The adaptive correction method for the installation angle of a swashplate phase-scanning radar according to claim 1, characterized in that, Step 3, which involves converting the target's centroid from the geographic system to the radar system, is as follows: Transition from Geography System to Stable System: in The inertial navigation angle before the array rotates; Geography system transformation matrix in , , , and Let the inertial navigation climb angle and roll angle be the inertial navigation angles before the array rotates, respectively. Then, the azimuth and pitch angles of the stable system corresponding to the target's centroid are respectively: Stable azimuth angle Pitch angle Stable system transformation variables: Stable system transformation matrix in and Let the forward and elevation installation angles of the array be the forward and elevation angles, respectively. Then, the radar system azimuth and elevation angles corresponding to the target's centroid are as follows: Azimuth Pitch angle .

4. The adaptive correction method for the installation angle of the swashplate phase-scanning radar according to claim 3, characterized in that, In step 3 The azimuth installation angle correction value is: Where Θ is the angle transformation correction value, which takes the value (0, π); The installation angle is the orientation after rotation; The pitch installation angle correction value is: in, 。 5. The adaptive correction method for the installation angle of the swashplate phase-scanning radar according to claim 4, characterized in that, In step 4, by Installation angle of formula correction Recalculate the target geographic system angle.

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