A method for estimating detection parameters of a forward-looking detector based on volume targets

Abstract

This invention belongs to the field of detection simulation and signal processing, and discloses a method for estimating detection parameters of a forward-looking detector based on a volume target. The method includes the following steps: analyzing the detector and target models using forward-looking detection model simulation software; determining the target attitude and relative motion trajectory through coordinate transformation based on imported parameters; determining the target center position detected by the detector by judging visible elements and mutual occlusion; processing the distance vector and relative velocity vector to obtain the detection values ​​in the detector coordinate system; converting the three-dimensional motion model into a two-dimensional planar motion model; analyzing and processing the measurement data to complete the encounter parameter estimation. This invention addresses the situation where the detector can only measure distance during the encounter segment under forward-looking detection conditions, proposing an encounter parameter estimation method based on a two-dimensional plane. Furthermore, the target position estimation is more consistent with reality and has higher reliability.

Description

Technical Field

[0001] This invention belongs to the field of detection simulation and signal processing technology, and relates to a forward-looking detector start-up point control algorithm, and in particular to a method for estimating detection parameters of a forward-looking detector based on a volume target. Background Technology

[0002] With the increasing maturity of hypersonic technology, side-looking detectors, due to limitations in their system design, can only detect targets at close range. When facing hypersonic targets, they are prone to significant delays in detecting the impact point. Therefore, the emergence of forward-looking detector technology has become inevitable. Forward-looking detection technology changes the previous approach of detectors relying on lateral target detection for activation control. It uses an active terminal guidance system to detect and process targets, and then predicts the target's aiming point using predictive algorithms.

[0003] When estimating encounter parameters for forward-looking detection, existing measurement models such as ranging and angle measurement, velocity and angle measurement, while introducing considerable measurement errors due to factors such as internal noise, target noise, target motion, multipath effects, inconsistent amplitude and phase characteristics of single-pulse receiving channels, and imperfect data processing, can effectively control the starting point error through appropriate data processing methods and the completeness of the data required by the measurement model. However, when the detector can only measure distance during the encounter phase, the limited information acquired by the detector, including the lack of angular information, makes encounter parameter estimation significantly more difficult.

[0004] In addition, existing simulation methods for detecting target positions using analog detectors typically involve directly taking the target's center or finding the intersection point between the equivalent detection line and the target. Compared to finding visible elements of a volume target, these two methods require less computation, but their accuracy in simulating real-world situations decreases during motion. Therefore, it is necessary to improve upon existing technologies to address these issues. Summary of the Invention

[0005] The purpose of this invention is to address the problems mentioned in the background art by proposing a method for estimating detection parameters of a forward-looking detector based on a volumetric target. The technical problems to be solved are: existing simulations directly use the target center or other specified locations as measurement points; however, due to the influence of factors such as the volumetric target's attitude and shape, the data obtained from such measurements does not match the actual situation, resulting in deviations in the simulation data; for situations where the detector in the encounter segment can only measure distance, encounter parameter estimation is quite difficult, and an alternative miss distance estimation and start-up point control algorithm has been proposed; this invention is precisely designed to solve these problems.

[0006] To achieve the objective of this invention, a method for estimating detection parameters of a forward-looking detector based on a volume target is disclosed, comprising the following steps:

[0007] Step 1: Import the target and detector models into the forward-looking detection model simulation software, and import the rendezvous parameters using the interface input or data file method;

[0008] Step 2: Determine the target attitude and relative motion trajectory by performing coordinate transformation based on the imported parameters;

[0009] Step 3: Determine the target center location detected by the fuse by judging visible elements and mutual obstruction;

[0010] Step 4: Process the distance vector and relative velocity vector to obtain the detected values ​​in the detector coordinate system;

[0011] Step 5: Establish a three-dimensional motion model, convert it into a two-dimensional planar motion model, process the measurement data, and complete the encounter parameter estimation.

[0012] Furthermore, in step 2, coordinate transformation is used to determine the missile's attitude and relative motion trajectory, specifically including the following steps:

[0013] Step 2-1: Perform coordinate transformation on the vertex data of the detector and target surface elements, and perform roll angle transformation, pitch angle transformation, and yaw angle transformation in sequence;

[0014] Step 2-2: Let the speed of the detector and the target be V. m V t Their respective velocity vectors in the ground coordinate system are

[0015]

[0016] In the two equations above, M x [Roll] is the roll angle transformation matrix, M y [Yaw] is the yaw angle transformation matrix, M z [Pitch] is the pitch angle transformation matrix, M z [AoA] is the angle of attack transformation matrix, M y [AoS] is the sideslip angle transformation matrix;

[0017] Therefore, the relative velocity vector is obtained.

[0018] Steps 2-3: Combine the off-target point parameters to determine the relative motion trajectory.

[0019] Further, in step 3, visible element judgment and mutual occlusion judgment are performed based on relative positions to calculate the target position detected by the simulated detector. This specifically includes the following steps:

[0020] Step 3-1: Visual element judgment;

[0021] Whether a surface element of the target model is visible within the detection field can be determined by whether the surface element is illuminated by the incident wave and whether the echo direction of the surface element can be received by the receiver. The specific determination method is as follows: read out the outward normal of all surface elements of the target in the target coordinate system; then, for any triangular surface element S, calculate the outward normal. with the direction vector of the incident wave The inner product is used to calculate the outer normal. With the receiving direction vector The inner product; when When, surface element S can be illuminated by the incident wave, when At that time, surface element S can be detected by the receiver; therefore, only when both conditions are met simultaneously... and Only the surface elements within the detection area are visible surface elements;

[0022] Step 3-2: Perform mutual occlusion judgment between visible pixels;

[0023] The mutual occlusion between surface elements is caused by the proximity relationship between the location of the detection site and the numerous surface elements of the target; similarly, the occluded surface elements do not contribute to the target echo, and such surface elements need to be judged as invisible during calculation.

[0024] Specifically, a line segment is drawn from the detection point, and the other end of the line segment is the centroid of the face element to be judged. If the line segment passes through a face element between the two endpoints, the face element is judged to be invisible; otherwise, the face element is judged to be visible and stored in the visible face element linked list.

[0025] Step 3-3: Calculate the simulated target location detected by the detector;

[0026] Based on the obtained visible surface metadata, the centroid position of the obtained visible surface elements is calculated, and the average value is taken to calculate the target center point detected by the detector.

[0027] Further, in step 4, the relative velocity vector and distance vector in the intersection model in the ground coordinate system are transformed and processed to obtain measurement data in the detector coordinate system. This specifically includes the following steps:

[0028] The initial detector coordinate system 3-axis unit vector is denoted as

[0029]

[0030] After attitude angle transformation, the 3-axis unit vector of the detector coordinate system in the ground coordinate system is:

[0031]

[0032]

[0033] Let M be the coordinate point of the detection center in the ground coordinate system, and P be the position of the detected target center. Then, the measured values ​​in the detector coordinate system are as follows:

[0034]

[0035] R x R y R z To determine the target location detected in the detector coordinate system, VR x VR y VR z It refers to the components of the velocity vector on the three axes in the detector coordinate system.

[0036] Furthermore, in step 5, a three-dimensional motion model is established, which is then transformed into a two-dimensional planar motion model. The measurement data is then processed to complete the encounter parameter estimation.

[0037] To address the situation where the forward-looking detector can only measure distance during the encounter phase, a measurement model in the detector coordinate system is established. Since the miss plane is defined as a plane perpendicular to the relative motion trajectory, the three-dimensional motion model is simplified to a two-dimensional motion plane composed of the detector, the target, and the miss point.

[0038] At the end of the flight, the distance is only a few hundred meters. When dealing with typical hypersonic targets, the relative speed reaches several thousand meters, and the maneuverability is limited. The remaining flight time is only a few hundred or even tens of milliseconds. It is assumed that the target and the detector are moving in uniform linear motion at this time. In the derivation of the model below, it is assumed that the detector and the target are moving in uniform linear motion.

[0039] Let the distances from the target to the miss point in the first three ranging measurements be l1, l2, and l3, which form an arithmetic sequence.

[0040] l1-l2=l3-l2=d

[0041] Furthermore, the distances R1, R2, and R3 measured in the first three measurements have the following relationship with l1, l2, and l3.

[0042]

[0043] Solving the two equations simultaneously, we get

[0044]

[0045] The expression for relative velocity v is

[0046]

[0047] The miss distance ρ can be expressed as

[0048]

[0049] Therefore, in the detector coordinate system, based on the above analysis, the distance of the target from the miss plane and the motion step size at each time interval t1 can be obtained from the three measurements, and the relative velocity can also be obtained; however, knowing the above information is still insufficient for us to calculate the warhead activation delay more accurately. In this case, we can think of a way to use the existing information to find a relatively reasonable activation point control algorithm; assuming the magnitude of the kill element's flight velocity is V f The remaining flight time is defined here as the time required for the target to move to the miss plane. The kill element flight time is obtained by dividing the miss distance ρ by the kill element's flight velocity. Thus, the start-up delay after the detector performs the third measurement can be expressed as...

[0050]

[0051] By transforming the three-dimensional rendezvous process into a two-dimensional plane for analysis, an expression for the startup delay in the absence of angle information was obtained. Obviously, this expression is not accurate enough, but when the detector encounters a target and can only measure distance, this method can estimate a value close to the ideal startup delay. The reliability of the startup delay estimate is higher when the rendezvous angle is small, and the computational load of this method is very small, with good real-time performance. In scenarios where information is limited, this is a relatively reliable startup delay estimation algorithm.

[0052] Compared with existing technologies, the significant advancements of this invention are as follows: This invention obtains the target position of the detection simulation through the judgment of visible elements and data processing, and transforms the distance vector and relative velocity vector in the ground coordinate system into the measured values ​​in the detector coordinate system through coordinate transformation and vector calculation. Compared with the method of directly taking the center of the target or the intersection point of the equivalent detection line and the target as the detection point, the reliability is higher. For the case where the fuze can only measure the distance in the encounter section, an alternative miss distance estimation and start-up point control algorithm is proposed, which effectively ensures the accuracy of start-up point control.

[0053] To more clearly illustrate the functional characteristics and structural parameters of the present invention, further explanation is provided below in conjunction with the accompanying drawings and specific embodiments. Attached Figure Description

[0054] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this application, illustrate exemplary embodiments of the invention and, together with their description, serve to explain the invention and do not constitute an undue limitation thereof. In the drawings:

[0055] Figure 1 This is a flowchart of a method for estimating detection parameters of a forward-looking detector based on a volume target.

[0056] Figure 2 This is a schematic diagram of the intersection model in the detector coordinate system. Point D is the miss point, which is the intersection of the relative motion trajectory and the miss plane. Point E is the intersection of the relative motion trajectory and the detector coordinate system Y. m OZ m Intersection of planes;

[0057] Figure 3 It is Figure 2 The model after the three-dimensional intersection model is converted into a two-dimensional plane. Detailed Implementation

[0058] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0059] like Figure 1 As shown, a method for estimating detection parameters of a forward-looking detector based on a volume target is implemented as follows:

[0060] S1. Import the existing target and detector models into the software. Given that the attitude angles, angles of attack, sideslip angles, velocity magnitudes, miss distances, and miss azimuths of the detector and target are known, the motion trajectory is uniquely determined. The rendezvous trajectory is generated by inputting the above parameters through the interface or by reading data files.

[0061] S2. Perform coordinate transformations on the vertex data of the detector and target surfaces, sequentially performing roll angle transformation, pitch angle transformation, and yaw angle transformation. Let the magnitudes of the detector and target velocities be V. m V t Their respective velocity vectors in the ground coordinate system are

[0062]

[0063] In the two equations above, M x [Roll] is the roll angle transformation matrix, M y [Yaw] is the yaw angle transformation matrix, M z [Pitch] is the pitch angle transformation matrix, M z [AoA] is the angle of attack transformation matrix, M y [AoS] is the sideslip angle transformation matrix.

[0064] From this, the relative velocity vector can be obtained. Then, by combining the parameters of the miss point, the relative motion trajectory is determined.

[0065] S3. Based on relative position, determine the visibility of surface elements. Whether a surface element of the target model is visible within the detection field can be determined by whether the surface element is illuminated by the incident wave and whether the echo direction of the surface element can be received by the receiver. Specifically, read the outward normal of all surface elements of the target in the target coordinate system. Then, for any triangular surface element S, calculate the outward normal. with the direction vector of the incident wave The inner product is used to calculate the outer normal. With the receiving direction vector The inner product. When When, surface element S can be illuminated by the incident wave, when At that time, surface element S can be detected by the receiver. Therefore, only when both conditions are met... and The surface element is the visible surface element within the detection area.

[0066] S4. Perform mutual occlusion judgment between visible pixels;

[0067] The mutual occlusion between surface elements is caused by the proximity of the detection site to the target's numerous surface elements. Similarly, occluded surface elements do not contribute to the target echo and must be considered invisible during calculation.

[0068] Specifically, a line segment is drawn from the detection point, with the other endpoint of the line segment being the centroid of the surface element to be judged. If the line segment passes through a surface element between the two endpoints, this surface element is judged as invisible; otherwise, it is judged as visible and stored in the visible surface element linked list. Based on the obtained visible surface element data, the centroid positions of the obtained visible surface elements are calculated, and the average is taken to calculate the target center point detected by the detector.

[0069] S5. Obtain the measurement data in the detector coordinate system from the relative velocity vector and distance vector in the intersection model in the ground coordinate system through coordinate transformation and data processing. This includes the following steps:

[0070] The initial detector coordinate system 3-axis unit vector is denoted as

[0071]

[0072] After attitude angle transformation, the 3-axis unit vector of the detector coordinate system in the ground coordinate system is:

[0073]

[0074] Let M be the coordinate point of the detection center in the ground coordinate system, and P be the position of the detected target center. Then the measured values ​​in the detector coordinate system are as follows.

[0075]

[0076] R x R y R z To determine the detected target position in the detector coordinate system, VR x VR y VR z It refers to the components of the velocity vector on the three axes in the detector coordinate system.

[0077] S6. Establish a measurement model in the detector coordinate system, such as Figure 2 As shown, for situations where the forward-looking detector can only measure distance during the encounter phase, since the miss plane is defined as a plane perpendicular to the relative trajectory, the three-dimensional motion model of the missile and target can be simplified to a two-dimensional motion plane composed of the missile, target, and miss point, as follows. Figure 3 As shown.

[0078] At the end of flight, the relative distance is only a few hundred meters. When dealing with typical hypersonic targets, the relative speed reaches several thousand meters, and maneuverability is limited. The remaining flight time is only a few hundred or even tens of milliseconds. It can be assumed that the detector and the target are moving in uniform linear motion at this time. In the derivation of the model below, we assume that the detector and the target are moving in uniform linear motion.

[0079] Let the distances from the target to the miss point in the first three ranging measurements be l1, l2, and l3, which form an arithmetic sequence.

[0080] l1-l2=l3-l2=d

[0081] Furthermore, the distances R1, R2, and R3 measured in the first three measurements have the following relationship with l1, l2, and l3.

[0082]

[0083] Solving the two equations simultaneously, we get

[0084]

[0085] The expression for relative velocity v is

[0086]

[0087] The miss distance ρ can be expressed as

[0088]

[0089] Therefore, in the detector coordinate system, based on the above analysis, the distance of the target from the miss plane and the motion step size at each time interval t1 can be calculated from the three measurements, and the relative velocity can also be obtained. However, knowing the above information is still insufficient for calculating a relatively accurate warhead activation delay. In this case, a method can be considered to use the existing information to find a relatively reasonable activation point control algorithm. Assume that the designed warhead kill element has a flight velocity of V. f The remaining flight time is defined here as the time required for the target to move to the miss plane. The kill element flight time is obtained by dividing the miss distance ρ by the kill element's flight velocity. Thus, the start-up delay after the detector performs the third measurement can be expressed as...

[0090]

[0091] By transforming the three-dimensional rendezvous process into a two-dimensional plane for analysis, a startup delay expression was obtained under conditions of insufficient angle information. Obviously, this expression is not accurate enough. However, when the detector encounters an object and can only measure distance, this method can estimate a value close to the ideal startup delay. The reliability of the startup delay estimate increases when the rendezvous angle is small. Furthermore, this method has low computational complexity and good real-time performance. In scenarios with limited information, this is a relatively reliable startup delay estimation algorithm.

[0092] It is not difficult to see from the above expressions and reasoning that the estimation accuracy of the activation delay is closely related to the angle between the relative velocity and the x-axis of the detector coordinate system. As the angle between the relative velocity and the x-axis of the detector coordinate system increases, the estimation error of the detonation delay will become larger and larger. This is because when the angle between the relative velocity and the x-axis of the detector coordinate system is large, the estimation of the remaining flight time will fluctuate significantly, and the estimated flight time of the kill element may be underestimated, resulting in an overall deviation in the activation delay.

[0093] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0094] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for estimating detection parameters of a forward-looking detector based on a volume target, characterized in that, Includes the following steps: Step 1: Import the target and detector models into the forward-looking detection model simulation software, and import the rendezvous parameters using the interface input or data file method; Step 2: Determine the target attitude and relative motion trajectory by performing coordinate transformation based on the imported parameters; Step 3: Determine the target center location detected by the fuse by judging visible elements and mutual obstruction; Step 4: Process the distance vector and relative velocity vector to obtain the detected values ​​in the detector coordinate system; Step 5: Establish a three-dimensional motion model, convert it into a two-dimensional planar motion model, process the measurement data, and complete the encounter parameter estimation; In step 5, a three-dimensional motion model is established, which is then transformed into a two-dimensional planar motion model. The measurement data is processed to complete the encounter parameter estimation. To address the situation where the forward-looking detector can only measure distance during the encounter phase, a measurement model in the detector coordinate system is established. Since the miss plane is defined as a plane perpendicular to the relative motion trajectory, the three-dimensional motion model is simplified to a two-dimensional motion plane composed of the detector, the target, and the miss point. At the end of the flight, the distance is only a few hundred meters. When dealing with typical hypersonic targets, the relative speed reaches several thousand meters, and the maneuverability is limited. The remaining flight time is only a few hundred or even tens of milliseconds. It is assumed that the target and the detector are moving in uniform linear motion at this time. In the derivation of the model below, it is assumed that the detector and the target are moving in uniform linear motion. Let the distances from the target to the miss point in the first three ranging measurements be l1, l2, and l3, which form an arithmetic sequence. l1-l2＝l3-l2＝d Furthermore, the distances R1, R2, and R3 measured in the first three measurements have the following relationship with l1, l2, and l3. Solving the two equations simultaneously, we get The expression for relative velocity v is The miss distance ρ is expressed as Therefore, in the detector coordinate system, through the above analysis, the distance of the target from the miss plane and the motion step size at each time interval t1 are both obtained from three measurements, and the relative velocity can also be obtained; assuming the magnitude of the kill element's flight velocity is V f The remaining flight time is defined here as the time required for the target to reach the miss plane. The kill element flight time is obtained by dividing the miss distance ρ by the kill element's flight velocity. The start-up delay after the detector performs its third measurement is expressed as... By transforming the three-dimensional intersection process into a two-dimensional plane for analysis, we obtain the start-up delay expression in the absence of angle information.

2. The method for estimating detection parameters of a forward-looking detector based on a volume target according to claim 1, characterized in that, In step 2, coordinate transformation is used to determine the missile's attitude and relative motion trajectory, specifically including the following steps: Step 2-1: Perform coordinate transformation on the vertex data of the detector and target surface elements, and perform roll angle transformation, pitch angle transformation, and yaw angle transformation in sequence; Step 2-2: Let the speed of the detector and the target be V. m V t Their respective velocity vectors in the ground coordinate system are In the two equations above, M x [Roll] is the roll angle transformation matrix, M y [Yaw] is the yaw angle transformation matrix, M z [Pitch] is the pitch angle transformation matrix, M z [AoA] is the angle of attack transformation matrix, M y [AoS] is the sideslip angle transformation matrix; Therefore, the relative velocity vector is obtained. Steps 2-3: Combine the off-target point parameters to determine the relative motion trajectory.

3. The method for estimating detection parameters of a forward-looking detector based on a volume target according to claim 1, characterized in that, In step 3, visible element identification and mutual occlusion identification are performed based on relative positions to calculate the target position detected by the simulated detector. This specifically includes the following steps: Step 3-1: Visual element judgment; Whether a surface element of the target model is visible within the detection field is determined by whether the surface element can be illuminated by the incident wave and whether the echo direction of the surface element can be received by the receiver. Specifically, the determination method is as follows: read the outward normal of all surface elements of the target in the target coordinate system; then, for any triangular surface element S, calculate the outward normal. with the direction vector of the incident wave The inner product is used to calculate the outer normal. With the receiving direction vector The inner product; when When, surface element S can be illuminated by the incident wave, when At that time, surface element S can be detected by the receiver; therefore, only when both conditions are met simultaneously... and Only the surface elements within the detection area are visible surface elements; Step 3-2: Perform mutual occlusion judgment between visible pixels; The mutual occlusion between surface elements is caused by the proximity relationship between the location of the detection site and the numerous surface elements of the target; similarly, the occluded surface elements do not contribute to the target echo, and such surface elements need to be judged as invisible during calculation. Specifically, a line segment is drawn from the detection point, and the other end of the line segment is the centroid of the face element to be judged. If the line segment passes through a face element between the two endpoints, the face element is judged to be invisible; otherwise, the face element is judged to be visible and stored in the visible face element linked list. Step 3-3: Calculate the simulated target location detected by the detector; Based on the obtained visible surface metadata, the centroid position of the obtained visible surface elements is calculated, and the average value is taken to calculate the target center point detected by the detector.

4. The method for estimating detection parameters of a forward-looking detector based on a volume target according to claim 1, characterized in that, In step 4, the relative velocity vector and distance vector in the intersection model in the ground coordinate system are transformed and processed to obtain the measurement data in the detector coordinate system. This specifically includes the following steps: The initial detector coordinate system 3-axis unit vector is denoted as After attitude angle transformation, the 3-axis unit vector of the detector coordinate system in the ground coordinate system is: Let M be the coordinate point of the detection center in the ground coordinate system, and P be the position of the detected target center. Then, the measured values ​​in the detector coordinate system are as follows: R x R y R z To determine the target location detected in the detector coordinate system, VR x VR y VR z It refers to the components of the velocity vector on the three axes in the detector coordinate system.

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