A method for judging failure of an aerial target based on ground-directed acceleration characteristics

Abstract

The application discloses a method for judging the failure of an aerial target based on the characteristics of the earthward acceleration, which utilizes the characteristics that the earthward acceleration of the target after failure is distributed around the gravity acceleration, calculates the weighted integral result of the characteristic parameter of the earthward acceleration of the target with respect to time within a specific time, and judges whether the target is failed and the failure probability of the target. The method for judging the failure of the aerial target based on the characteristics of the earthward acceleration effectively improves the accuracy of the failure judgment of the target based on the motion characteristics, and greatly reduces the time delay of the failure judgment.

Description

Technical Field

[0001] This invention belongs to the field of target failure determination, and particularly relates to a method for determining the failure of aerial targets based on motion characteristics. Background Technology

[0002] Aerial target failure determination technology is crucial for command and control decisions. It utilizes acquired optical or kinematic image information of aerial targets, and through a series of feature extraction and data processing steps, determines whether the target is failed and the probability of failure. To achieve high-speed and accurate failure determination, it is often necessary to fuse failure determination results based on optical images and those based on motion features.

[0003] Currently, there is considerable research on failure determination based on optical images, and the solutions are relatively mature. However, research on failure determination based on motion features is limited, and the main existing methods are based on changes in velocity direction. The core idea of ​​this method is to utilize the abrupt changes in the target's trajectory after failure, judging the probability of failure by the magnitude of the change in the target's velocity direction over a specific time period. While this method achieves good failure determination performance when the target is moving smoothly in the air, it fails when the target performs large maneuvers. Even if the target is not actually failed, the algorithm will still detect abrupt changes in the target's velocity direction, incorrectly classifying it as failed. This results in low accuracy and fails to meet the requirements of efficient and intelligent decision-making. Summary of the Invention

[0004] In view of this, in order to overcome the problem of low accuracy of existing air target failure determination methods based on velocity direction changes, this invention provides an air target failure determination method based on ground acceleration characteristics. This method utilizes the characteristic that the ground acceleration of an air target after failure is distributed near the gravitational acceleration, calculates the weighted integral result of the ground acceleration characteristic parameter of the target over a specific time period, and uses the weighted integral result to determine whether the target has failed and to determine the probability of failure.

[0005] To achieve this objective, the present invention adopts the following technical solution: a method for determining the failure of an aerial target based on ground acceleration characteristics, the method comprising:

[0006] S1: Periodically sample the trajectory of the aerial target to obtain N sampling points;

[0007] S2: Obtain the velocity vectors of N sampling points of an aerial target at the corresponding time points;

[0008] S3: Calculate the ground acceleration of the air target at N sampling points at the corresponding time based on the velocity vector;

[0009] S4: Calculate the failure confidence parameters of the N sampling points of the air target at the corresponding time.

[0010] S5: Calculate the instantaneous failure probability of an aerial target at the corresponding time points of N sampling points;

[0011] S6: Calculate the failure probability of an air target at any sampling point at any given time, and determine whether the air target has failed at the corresponding time of that sampling point based on the failure probability.

[0012] S7: Repeat step S6 until the determination of whether the air target is invalid at all sampling points is completed.

[0013] Preferably, in step S4, the failure confidence parameter is calculated as follows:

[0014]

[0015] Where w() represents the failure confidence parameter of the airborne target, a g () represents the ground acceleration of an aerial target, g represents the gravitational acceleration, σ represents the ground acceleration characteristic adjustment parameter; 1≤n≤N, represents the nth sampling point, and T is the duration of the sampling period.

[0016] Preferably, in step S5, the instantaneous failure probability is calculated as follows:

[0017]

[0018] Where p d () represents the instantaneous failure probability, and λ represents the instantaneous failure probability adjustment factor.

[0019] Preferably, in step S6, the failure probability at any sampling point is obtained by weighted integral of the instantaneous failure probabilities of air targets within the range from the start time to the time corresponding to that sampling point.

[0020] Preferably, in step S6, the failure probability is calculated as follows:

[0021] p(nT)=e -ηT p((n-1)T)+p d (t)(1-e -ηT )

[0022] Where p() represents the target failure probability; η represents the memory factor.

[0023] Preferably, in step S6, the method for determining whether an aerial target has failed is as follows:

[0024]

[0025] in This represents whether the algorithm determines the target has failed at a certain moment, where 0 indicates the target is not failed and 1 indicates the target has failed. ε This represents the failure probability threshold.

[0026] The beneficial effects of this invention are as follows: The aerial target failure determination method based on ground acceleration characteristics disclosed in this invention utilizes the characteristic that the ground acceleration distribution after a target failure is near the gravitational acceleration to calculate the weighted integral result of the ground acceleration characteristic parameter of the target over a specific time period. Based on this result, it determines whether the target has failed and the probability of target failure. This method can accurately determine whether the target has failed and the probability of failure under the condition of large target maneuvering, which greatly improves the accuracy of trajectory-based target failure determination. Attached Figure Description

[0027] Figure 1 This is a flowchart of the aerial target failure determination method based on ground acceleration characteristics in an embodiment of the present invention;

[0028] Figure 2 This is the normal flight trajectory of the target in the northeast-sky coordinate system in this embodiment of the invention;

[0029] Figure 3 This is the target failure flight trajectory in the northeast-sky coordinate system in this embodiment of the invention. Detailed Implementation

[0030] Those skilled in the art will recognize that the embodiments described herein are intended to help the reader understand the principles of the invention, and should be understood that the scope of protection of the invention is not limited to such specific statements and embodiments. Those skilled in the art can make various other specific modifications and combinations based on the technical teachings disclosed in this invention without departing from the spirit of the invention, and these modifications and combinations are still within the scope of protection of this invention.

[0031] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0032] One such Figure 1 The method shown is an aerial target failure determination method based on ground acceleration characteristics. This method utilizes the characteristic that the ground acceleration of a target after failure is distributed near the gravitational acceleration, calculates the weighted integral of the ground acceleration characteristic parameters of the target over a specific time period, and uses this result to determine whether the target has failed and the probability of target failure.

[0033] As an example, the method first performs periodic sampling on the trajectory of the aerial target to obtain N sampling points, and then obtains the velocity vector of the aerial target at the corresponding time of the N sampling points.

[0034] Next: Calculate the ground acceleration of the aerial target at each sampling point, as shown below:

[0035]

[0036] Where a g () represents the acceleration of the target relative to the ground at a specific moment, v u () represents the celestial velocity of the target in the geographic coordinate system at a specific moment, 1≤n≤N, represents the nth sampling point, and T is the duration of the sampling period.

[0037] Then: Calculate the failure confidence parameter of the airborne target at the sampling point time based on the calculated acceleration, as follows:

[0038]

[0039] Where w() represents the failure confidence parameter of the airborne target, a g () represents the ground acceleration of an aerial target, g represents gravitational acceleration, and σ represents the ground acceleration characteristic adjustment parameter;

[0040] Next: The failure confidence weights are transformed within the range of [0,1] to obtain the instantaneous failure probability of the airborne target at the sampling point, as shown below:

[0041]

[0042] Where p d () represents the instantaneous failure probability, and λ represents the instantaneous failure probability adjustment factor. Instantaneous failure probability p d () represents the probability of target failure determined using only the data at time t.

[0043] Further: The instantaneous failure probability p determined at the nth sampling point d The final failure decision probability is obtained by weighting the integral of (nT) with the failure probabilities of the first (n-1) sampling points:

[0044] p(nT)=e -ηT p((n-1)T)+p d (nT)(1-e -ηT )

[0045] Where p() represents the target failure probability; η represents the memory factor. The failure probability calculated by p(nT) is the weighted integral of the instantaneous failure probability over the time interval [0, nT]. Its weight decays exponentially over time, and the further back in time it is from the current moment, the smaller the weight becomes.

[0046] Finally: Determine whether the aerial target is invalid at the nth sampling point:

[0047]

[0048] in p represents whether the algorithm determines the target has failed at a certain moment (0 represents the target has not failed, 1 represents the target has failed). ε This represents the failure probability threshold. When the failure probability of the target evaluated by the algorithm is greater than this threshold, the target is determined to be failed.

[0049] Repeat the above steps until all n sampling points have been processed, and output whether the target has failed and the probability of failure for each sampling time period.

[0050] Example 1

[0051] The method proposed in this invention was used to determine the failure of 408 simulated trajectories of the same type of aerial target. Of these, 204 trajectories were those of normal target flight, meaning no damage was caused after the attack; the other 204 trajectories were considered failure trajectories, indicating that after being attacked, the target's control system was unable to maintain normal attitude and velocity control, and the target's motion in the air gradually became uncontrollable. Examples of the two types of trajectories are shown below. Figure 2 and Figure 3 As shown.

[0052] When applying the method of the present invention, as an example, the corresponding parameters are set as follows: each sampling time period T = 0.01s, ground acceleration characteristic adjustment parameter σ = 0.5g, instantaneous failure probability adjustment factor λ = 4, memory factor η = 4, and failure probability threshold p. ε =0.9.

[0053] This section primarily evaluates two types of performance metrics for failure decision algorithms:

[0054] 1) Accuracy of invalidation judgments

[0055] For the m-th target trajectory, the precise definition of the trajectory determination is as follows:

[0056]

[0057] Where P m The failure of a decision on m trajectories is determined by whether the decision is accurate (0 represents an inaccurate decision, 1 represents an accurate decision), I m , τ represents the true value and estimated value of whether the target ultimately fails in the m-th trajectory (0 represents the target is not failed, 1 represents the target is failed), respectively. m , τ represents the true value and estimated value at the moment when the target begins to fail, respectively (if the target does not fail in the m-th trajectory, then τ...). m=+∞). The above formula shows that, for a single trajectory, the failure assessment module's decision is accurate in two cases: (1) the target is not actually failed, and the algorithm also determines that the target is not failed; (2) the target is actually failed, the algorithm determines that the target is failed, and the time when the algorithm determines that the target is failed is later than the time when the target is actually failed.

[0058] For M target trajectories, the accuracy of the failure decision module is as follows:

[0059]

[0060] 2) Average time to complete invalidation decision

[0061] For M target trajectories, the average time taken by the algorithm to complete the failure decision is as follows:

[0062]

[0063] Where card(·) represents the number of elements in the set Ω M The definition is as follows:

[0064]

[0065] As shown in Table 1, the failure decision rate of the method of the present invention reaches 100%, and the average time to complete the failure decision is 1.59s, while the accuracy rate of failure decision based on velocity direction change is only 84.8%, with an average time of 4.81s. Therefore, the method of the present invention can greatly improve the failure decision accuracy and reduce the failure decision time in failure decision based on motion characteristics.

[0066] Table 1. Accuracy and time of failure determination for different methods for the target

[0067] algorithm Accuracy of invalidation judgment Average time (s) to complete invalidation decision Failure Decision Based on Velocity Direction Change 84.8％ 4.81 Method of the present invention 100％ 1.59

Claims

1. A method for determining the failure of an aerial target based on ground acceleration characteristics, characterized in that, The method includes: S1: Periodically sample the trajectory of the aerial target to obtain... N One sampling point; S2: Acquire aerial target N The velocity vector at each sampling point at any given time; S3: Calculate aerial targets based on velocity vectors N The ground acceleration at each sampling point at the corresponding time; S4: Calculate aerial targets N Failure confidence parameters corresponding to each sampling point at each time point; S5: Calculate aerial targets N The instantaneous failure probability at each sampling point; S6: Calculate the failure probability of an air target at any sampling point at any given time, and determine whether the air target has failed at the corresponding time of that sampling point based on the failure probability. S7: Repeat step S6 until the determination of whether the air target is invalid at all sampling points is completed; In step S4, the failure confidence parameter is calculated as follows: in w () represents the failure confidence parameter of an aerial target. a g () represents the ground acceleration of an aerial target. g Represents gravitational acceleration. Indicates the ground acceleration characteristic adjustment parameter; 1≤ n≤N , indicating the first n There are 10 sampling points, where T is the duration of the sampling period; In step S5, the instantaneous failure probability is calculated as follows: in p d () represents the instantaneous failure probability. This represents the instantaneous failure probability adjustment factor; In S6, the failure probability at any sampling point is obtained by weighted integral of the instantaneous failure probabilities of air targets within the range from the start time to the time corresponding to that sampling point. In step S6, the failure probability is calculated as follows: in p () represents the probability of failure of an aerial target; Indicates memory factor; In step S6, the method for determining whether an aerial target has failed is as follows: in This represents whether the algorithm has determined the target to be invalid at a certain moment, where 0 indicates the target is not invalid and 1 indicates the target is invalid. This represents the failure probability threshold.

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