Light spot positioning method for four-quadrant detector of laser seeker

Abstract

The invention relates to the technical field of light spot positioning of intelligent sensors, in particular to a light spot positioning method of a laser seeker four-quadrant detector. The method comprises the following steps: constructing a light current matrix through light current, calculating light sensitivity based on the light current and absolute power, and forming a light sensitivity sequence; sorting the light current to obtain a light spot energy sequence, clustering the light current matrix to obtain a local light spot energy sequence, and obtaining an influence factor of the light current at the current moment on the light spot shape based on the characteristics of the local light spot energy sequence; the light sensitivity sequence and the light spot energy sequence are analyzed, and a light spot displacement deviation index at the current moment is obtained according to the trend, similarity and influence factors of the light sensitivity sequence and the light spot energy sequence; calculating the misalignment amount of the light spot center through the light spot energy, and calibrating the light spot center based on the light spot displacement deviation index to obtain the misalignment amount of the light spot center after calibration; and based on this, light spot areas of four quadrants are obtained, so that light spot positioning is realized. According to the invention, the accuracy of light spot positioning is optimized, and the positioning stability is improved.

Description

Technical Field

[0001] This application relates to the technical field of spot positioning of intelligent sensors, and particularly to a spot positioning method for a four-quadrant detector of a laser seeker. Background Art

[0002] The spot positioning technology of the four-quadrant detector of the laser seeker originated in the military field, especially in precision-guided weapon systems. Through its unique four-zone design, the four-quadrant detector can accurately measure the position of the laser spot relative to the center of the detector. The development of this technology enables the guidance system to adjust the flight path in real time, ensuring that the weapon system can accurately strike the target. The significance of this technology lies in that it greatly enhances the accuracy and reliability of the guidance system, and plays an important role in improving combat effectiveness and reducing unnecessary damage.

[0003] In the application of the laser seeker, the accuracy of spot positioning is crucial for the hitting accuracy of the guided weapon. Due to the uneven distribution of the spot on the detector, the offset of the spot centroid, and the change of the spot energy, the spot positioning will deviate, affecting the strike effect of the guided weapon. Specifically, the uneven distribution of the spot will cause the change of photocurrent, which in turn affects the measured value of the photosensitivity, making the spot positioning inaccurate. In addition, the offset of the spot centroid will cause uneven distribution of the spot on the detector, further affecting the stability and accuracy of the spot positioning. These positioning errors not only reduce the hit rate of the guided weapon, but also may lead to mission failure, resulting in waste of resources and potential safety risks. Summary of the Invention

[0004] In order to solve the technical problem of inaccurate spot positioning, this application provides a spot positioning method for a four-quadrant detector of a laser seeker. The specific technical solution adopted is as follows:

[0005] This application proposes a spot positioning method for a four-quadrant detector of a laser seeker. The method includes the following steps:

[0006] Based on the four-quadrant detector and its ammeter, collect the photocurrents of different quadrants to form a photocurrent matrix, and calculate the photosensitivity based on the photocurrent and the absolute power of the collected incident light to form a photosensitivity sequence;

[0007] Sort the sum values of the photocurrents of the four quadrants according to time to obtain a spot energy sequence; cluster the elements in the photocurrent matrix to obtain several clustering clusters, extract the spot energy sequence based on the moments corresponding to the clustering clusters to obtain the local spot energy sequence corresponding to each clustering cluster; obtain the influence factor of the photocurrent on the spot shape at the current moment according to the slope after fitting of the local spot energy sequence, the standard deviation of the number of all row elements in each clustering cluster, and the number of clustering clusters;

[0008] For the optical sensitivity sequence and the spot energy sequence, the p-value and z-value of each sequence are obtained through the Mann-Kendall test algorithm, and the trend function of the sequence is calculated based on the p-value and z-value of each sequence; according to the difference in the trend functions of the optical sensitivity sequence and the spot energy sequence, the cosine similarity between the optical sensitivity sequence and the spot energy sequence, and the influence factor of the photocurrent at the current moment on the spot shape, the spot displacement deviation index at the current moment is obtained;

[0009] Based on the spot energy in each quadrant, the offset of the spot center in different directions is calculated; and based on the offsets in different directions, the misalignment of the spot center is calculated; the misalignment of the spot center is calibrated through the spot displacement deviation index at the current moment to obtain the misalignment of the spot center after calibration, and the spot energy in each quadrant corresponds to the photocurrent in each quadrant;

[0010] The spot areas of the four quadrants are obtained through the misalignment of the spot center after calibration, thereby realizing spot positioning.

[0011] In the above solution, the present application proposes a spot positioning method for a four-quadrant detector of a laser seeker. Aiming at the problem of the influence of spot energy on photocurrent, the DBSCAN density clustering algorithm is used to reflect the influence of photocurrent on the change of spot shape, and the problem of the influence of spot shape change on positioning accuracy is solved; aiming at the deviation of the detector's response degree to optical signals, the Mann-Kendall test algorithm and cosine similarity are used to reflect the spot displacement deviation, excluding the influence of uneven spot energy distribution and optical sensitivity change. By calibrating the misalignment, by comprehensively considering the influence of spot shape change, spot displacement deviation and spot intensity, the position of the spot is effectively calibrated, the occurrence of extreme values is reduced, the stability of positioning is improved, and the actual distribution of the spot on the receiver is simulated by combining simulation calculations, further optimizing the accuracy of spot positioning, thereby providing a more reliable target tracking and striking ability for guided weapons.

[0012] In one embodiment, the method for collecting the photocurrents in different quadrants based on the four-quadrant detector and its ammeter to form a photocurrent matrix is as follows:

[0013] Taking each quadrant as each row and each acquisition moment as each column, the data collected in the preset time period before the current moment is statistically analyzed, and the photocurrents collected in all quadrants within this preset time period are constructed into a photocurrent matrix.

[0014] In one embodiment, the method for calculating the optical sensitivity based on the photocurrent and the absolute power of the incident light collected to form an optical sensitivity sequence is as follows:

[0015] Taking the sum of the photocurrents in all quadrants as the total quadrant current, and taking the ratio of the total quadrant current to the absolute power of the incident light as the optical sensitivity at each acquisition moment;

[0016] Ascendingly sort the optical sensitivities within a preset time period in chronological order to obtain an optical sensitivity sequence.

[0017] In one embodiment, the method for extracting the local spot energy sequence corresponding to each clustering cluster from the spot energy sequence based on the moments corresponding to the clustering clusters is as follows:

[0018] Each row in each clustering cluster corresponds to a start moment and an end moment. Extract the earliest start moment and the latest end moment in each clustering cluster, and use the data of the spot energy sequence within this time period as the local spot energy sequence of this clustering cluster.

[0019] In one embodiment, the method for obtaining the influence factor of the photocurrent at the current moment on the spot shape based on the slope after fitting the local spot energy sequence, the standard deviation of the number of elements in each row of all clustering clusters, and the number of clustering clusters is as follows:

[0020] For each clustering cluster, count the number of elements in each row in the clustering cluster, calculate the standard deviation of the number of elements in all rows, and use the standard deviation as the error weight of the clustering cluster;

[0021] Fit each local spot energy sequence to obtain its slope, and use the slope as the response sensitivity of the clustering cluster;

[0022] Calculate the influence factor of the photocurrent at the current moment on the spot shape based on the response sensitivities and error weights of all clustering clusters and the number of clustering clusters;

[0023] The influence factor is positively correlated with the response sensitivity of the clustering cluster and the error weight of the clustering cluster. In one embodiment, the expression of the influence factor of the photocurrent at the current moment on the spot shape is:

[0024] a n represents the error weight of the nth clustering cluster, b n represents the response sensitivity of the nth clustering cluster, N represents the number of clustering clusters, and A represents the influence factor of the photocurrent at the current moment on the spot shape.

[0025] In one embodiment, the method for calculating the trend function of the sequence based on the p value and z value of each sequence is as follows:

[0026] f x =z x ×g x ,p x represents the p value of the sequence x, g x represents the judgment function of the sequence x, z x represents the z value of the sequence x, fx The trend function representing sequence x.

[0027] In one embodiment, the method for obtaining the spot displacement deviation index at the current moment based on the difference in the trend functions of the light sensitivity sequence and the spot energy sequence, the cosine similarity between the light sensitivity sequence and the spot energy sequence, and the influence factor of the photocurrent at the current moment on the spot shape is as follows:

[0028] The spot displacement deviation index at the current moment is positively correlated with the difference in the trend functions of the light sensitivity sequence and the spot energy sequence, the cosine similarity between the light sensitivity sequence and the spot energy sequence, and the influence factor of the photocurrent at the current moment on the spot shape.

[0029] In one embodiment, the method for calculating the offset of the spot center in different directions based on the spot energy in each quadrant; and calculating the misalignment of the spot center based on the offsets in different directions is as follows:

[0030] E 1 ,E 2 ,E 3 ,E 4 are the spot energies of the first quadrant, the second quadrant, the third quadrant, and the fourth quadrant respectively, and σ x represents the offset of the spot center in the x direction, and σ y represents the offset of the spot center in the y direction;

[0031] The square root of the sum of the squares of the offsets of the spot center in the x direction and the y direction is calculated as the misalignment of the spot center.

[0032] In one embodiment, the method for calibrating the misalignment of the spot center through the spot displacement deviation index at the current moment to obtain the misalignment of the spot center after calibration is as follows:

[0033] Δ′ = 2tanh(B) × Δ, where Δ represents the misalignment of the spot center, B represents the spot displacement deviation index at the current moment, tanh() represents the hyperbolic tangent function, and Δ′ represents the misalignment of the spot center after calibration.

[0034] The beneficial effects of this application are:

[0035] The present application proposes a spot positioning method for a four-quadrant detector of a laser seeker. Aiming at the problem of the influence of spot energy on photocurrent, the DBSCAN density clustering algorithm is used to reflect the influence of photocurrent on the change of spot shape, so as to solve the problem of the influence of spot shape change on positioning accuracy. Aiming at the deviation of the corresponding degree of the detector to the light signal, the Mann-Kendal l test algorithm and cosine similarity are used to reflect the spot displacement deviation, and the influence of uneven spot energy distribution and light sensitivity change is eliminated. By calibrating the offset, the position of the spot is effectively calibrated by comprehensively considering the influence of spot shape change, spot displacement deviation and spot intensity, the occurrence of extreme values ​​is reduced, the stability of positioning is improved, and the actual distribution of the spot on the receiver is simulated by simulation calculation, so as to further optimize the accuracy of spot positioning, thereby providing guided weapons with more reliable target tracking and strike capabilities. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the technical solutions and advantages in the embodiments of the present application or the prior art, the drawings required for use in the embodiments or the prior art descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0037] Figure 1 A flow chart of a method for spot positioning of a four-quadrant detector of a laser seeker provided in one embodiment of the present application. DETAILED DESCRIPTION

[0038] In order to further explain the technical means and effects adopted by the present application to achieve the predetermined invention purpose, the following is a detailed description of the spot positioning method of a laser seeker four-quadrant detector proposed in the present application, its specific implementation method, structure, features and effects, in combination with the accompanying drawings and preferred embodiments. In the following description, different "one embodiment" or "another embodiment" does not necessarily refer to the same embodiment. In addition, specific features, structures or characteristics in one or more embodiments may be combined in any suitable form.

[0039] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.

[0040] An embodiment of a method for positioning a spot of a four-quadrant detector of a laser seeker:

[0041] The specific scheme of the spot positioning method of the four-quadrant detector of a laser seeker provided by the present application is described in detail below with reference to the accompanying drawings.

[0042] See also Figure 1, which shows a flowchart of a spot positioning method for a four - quadrant detector of a laser seeker provided by an embodiment of the present application. The method includes the following steps:

[0043] Step S001, construct a photocurrent matrix through photocurrents, calculate the photosensitivity based on the photocurrents and the absolute power, and form a photosensitivity sequence.

[0044] The four - quadrant detector (QPD) consists of four independent photodiodes (PD1, PD2, PD3, and PD4), which are closely arranged to form a square, thus forming four quadrants. Use an ammeter with high precision that can measure currents at the pA level, connect it to the photodiodes in each quadrant, and measure the output current of each photodiode as the photocurrent. These current values reflect the area of the spot on each quadrant of the detector and are related to the position of the spot; use a power meter to measure the absolute power of the incident light, and then measure the magnitude of the photocurrent of the photodiode under the same conditions; take the sum of the photocurrents of all quadrants as the total quadrant current, and calculate the photosensitivity at each acquisition moment through the total quadrant current and the absolute power of the incident light; in this embodiment, the specific calculation method of the photosensitivity is the ratio of the total quadrant current to the absolute power of the incident light. It should be noted that in this embodiment, the acquisition frequencies of the ammeter and the power meter are both set to 100 kHz to ensure that the acquisition intervals of the current data and the absolute power data of the incident light are consistent, and perform overall normalization processing on the current data of all quadrants collected and the calculated photosensitivity data to eliminate the influence of dimensions.

[0045] Take each quadrant as each row and each acquisition moment as each column, count the data collected in a preset time period before the current moment, construct a photocurrent matrix with the photocurrents collected from all quadrants within this preset time period, and sort the photosensitivity within the preset time period in ascending order of time to obtain a photosensitivity sequence. In this embodiment, the preset time period is 1 minute.

[0046] So far, the photosensitivity sequence and the photocurrent matrix are obtained.

[0047] Step S002, sort the photocurrents to obtain a spot energy sequence, cluster the photocurrent matrix to obtain a local spot energy sequence, and obtain the influence factor of the photocurrent at the current moment on the spot shape based on its characteristics.

[0048] The photocurrent matrix reflects the light energy received by each quadrant. When the spot moves on the four - quadrant detector, the light energy received by each quadrant will change, resulting in corresponding changes in the photocurrents of each quadrant. If the spot energy distribution is uneven, it will directly affect the data in the photocurrent matrix, and further affect the calculation of the spot center coordinates.

[0049] Let the photocurrents in the four quadrants be denoted as I 1 、I 2 、I 3 and I 4 . When the centroid of the light spot coincides with the center of the four - quadrant detector, since the illuminated area of each quadrant is equal, the photocurrents generated in the four quadrants are also equal, that is, I 1 = I 2 = I 3 = I 4 . Also, therefore, the sum of the photocurrents I 1 + I 2 + I 3 + I 4 1 , that is, the total quadrant current, which reflects the total energy of the light spot. And the equality of the photocurrents in each quadrant also indicates that the light spot is evenly distributed on the detector. When the centroid of the light spot deviates relative to the center of the detector, the illuminated areas of each quadrant will be different, resulting in different photocurrents generated in each quadrant. At this time, the total quadrant current still reflects the total energy of the light spot, but only the photocurrents in each quadrant are no longer equal. Therefore, all the total quadrant currents are sorted in ascending order of time to obtain the light - spot energy sequence.

[0050] As can be seen from the above analysis, the photocurrents in the four quadrants can reflect the area information of the light spot in each quadrant. Specifically, the magnitude of the photocurrent in each quadrant is proportional to the area of the light spot in that quadrant. For the photocurrent matrix, it is divided into several clustering clusters through a clustering algorithm; in this embodiment, it is processed through the DBSCAN density - clustering algorithm, with the minimum number of points set to 5 and the neighborhood radius set to 0.2. Thus, several clustering clusters are obtained. In the photocurrent matrix, each clustering cluster represents a region on the detector where the light spot has similar current characteristics, that is, at different acquisition times within a clustering cluster, the photocurrents in the same row (i.e., the same quadrant) can reflect similar light - spot areas.

[0051] For each clustering cluster, count the number of elements in each row of the clustering cluster, calculate the standard deviation of the number of elements in all rows, and use the standard deviation as the error - like weight of the clustering cluster; where each row in the clustering cluster is each row of the current matrix in the clustering cluster; that is, when the elements in the clustering cluster are in the same row in the current matrix, they are also in the same row in the clustering cluster. Then, based on the time of each clustering cluster, extract the light - spot energy sequence to reflect the response sensitivity of the photocurrent to the change in the light - spot energy; each row in each clustering cluster corresponds to a start time and an end time. Extract the earliest start time and the latest end time in each clustering cluster, and use the data of the light - spot energy sequence within this time period as the local light - spot energy sequence of this clustering cluster. Fit each local light - spot energy sequence to obtain its slope, and use the slope as the response sensitivity of the clustering cluster. In this embodiment, the fitting method used is the least - squares method.

[0052] Calculate the influence factor of the photocurrent at the current moment on the spot shape based on the response sensitivity and error weight of all clusters and the number of clusters.

[0053] The influence factor is positively correlated with the response sensitivity of the cluster and the product of the error weight of the cluster, and negatively correlated with the number of clusters.

[0054] It should be noted that positive correlation means that when one variable increases, the other variable also increases, and the change directions of the two variables are the same. When one variable changes from large to small or from small to large, the other variable also changes from large to small or from small to large; the specific relationship is determined by the actual application, and this application does not make special restrictions.

[0055] It should be noted that negative correlation means that when one variable increases, the other variable decreases accordingly, and the change directions of the two variables are opposite. When one variable changes from large to small or from small to large, the other variable also changes from small to large or from large to small; the specific relationship is determined by the actual application, and this application does not make special restrictions.

[0056] Preferably, in this embodiment, the expression of the influence factor of the photocurrent at the current moment on the spot shape is:

[0057] a n represents the error weight of the nth cluster, b n represents the response sensitivity of the nth cluster, N represents the number of clusters, and A represents the influence factor of the photocurrent at the current moment on the spot shape.

[0058] Among them, a n reflects the instability of the photocurrent at different moments within the same cluster. A smaller standard deviation means that the data points within the cluster are closer, indicating that the change in the photocurrent of the spot in this quadrant is smaller, that is, the spot is more stable; a n The larger the value of, the greater the variability of the photocurrent within the cluster, which means that the data in this cluster is not stable enough, and the data error within this cluster is stronger, and the value of A is larger; b n reflects the response sensitivity of the photocurrent to the change in spot energy. The larger its value means that a small change in spot energy will cause a significant change in the photocurrent, indicating that the detector is more sensitive to the change in spot energy, and the value of A is larger. A is used to evaluate the overall influence of the detector photocurrent on the change in spot shape. The larger the value of A, the more significant the influence of the photocurrent on the change in spot shape.

[0059] So far, the influence factor of the photocurrent at the current moment on the spot shape has been obtained.

[0060] Step S003: Analyze the optical sensitivity sequence and the spot energy sequence, and obtain the spot displacement deviation index at the current moment according to their trends, similarities, and influencing factors.

[0061] The spot energy characterized by the photocurrent in each quadrant refers to the energy distribution of the spot on the detector. The optical sensitivity is the ratio of the photocurrent to the absolute power of the incident light, indicating the response ability of the detector to the optical signal. The change in spot energy will directly affect the magnitude of the photocurrent, and thus affect the measured value of the optical sensitivity.

[0062] The optical sensitivity reflects the response ability of the detector to the optical signal. High optical sensitivity means that the detector has a stronger response to the optical signal, thereby improving the accuracy of spot positioning. If the centroid of the spot coincides with the center of the detector and the spot is evenly distributed on the detector, the optical sensitivity will remain relatively stable. Because the photodiodes in different quadrants receive different amounts of light energy, which affects their response, the centroid of the spot will shift, and the uneven distribution of the spot on the detector will lead to changes in the optical sensitivity.

[0063] Therefore, taking the optical sensitivity sequence as the input, using the Mann-Kendall test algorithm, setting the null hypothesis that the data has no trend and the alternative hypothesis that the data has a trend, and outputting the p-value and z-value of the optical sensitivity sequence. The Mann-Kendall test algorithm is a well-known technology. In the Mann-Kendall test algorithm, the z-value is the standardized statistic in the Mann-Kendall test, used to measure the significance of the data trend. When the z-value is positive, it indicates that the data has an upward trend, and the magnitude is proportional to the trend. The p-value represents the probability that the observed trend occurs purely by chance. The larger its value, the more accidental the trend tested by the z-value, and there is no general trend (the trend calculated by the z-value is less reliable). The smaller its value, the more general the trend tested by the z-value (the trend calculated by the z-value is more reliable).

[0064] The uniformity of the spot energy distribution can be analyzed through the spot energy sequence. Taking the spot energy sequence as the input, using the same method to output the p-value and z-value of the spot energy sequence. In addition, taking the optical sensitivity sequence and the spot energy sequence as the input, calculate the cosine similarity between the two sequences.

[0065] First, obtain the trend function of the sequence through the p-value and z-value of the sequence. The expression is:

[0066] f x = z x × g x , p x represents the p-value of sequence x, g x represents the judgment function of sequence x, z xDenote the z-value of sequence x, f x Denote the trend function of sequence x.

[0067] Among them, the trend function reflects the trend change of the sequence, z x The larger the value, the more obvious the trend of the sequence, g x The function g judges the significance of the trend according to the p-value. If p x <0.05, it indicates that the trend is significant. At this time, g x = p x ; If p x ≥0.05, it indicates that the trend is not significant. At this time, g x = 0. The larger the value of f x , the more obvious the trend of the sequence.

[0068] Obtain the spot displacement deviation index at the current moment according to the trend function difference between the light sensitivity sequence and the spot energy sequence, the influence factor of the photocurrent on the spot shape at the current moment, and the cosine similarity between the light sensitivity sequence and the spot energy sequence;

[0069] The spot displacement deviation index at the current moment is positively correlated with the trend function difference between the light sensitivity sequence and the spot energy sequence, the cosine similarity between the light sensitivity sequence and the spot energy sequence, and the influence factor of the photocurrent on the spot shape at the current moment.

[0070] Preferably, in this embodiment, the expression of the spot displacement deviation index is:

[0071] B = A × |c × (f i - f j )|, where f i represents the trend function of the light sensitivity sequence i, f j represents the trend function of the spot energy sequence j, c represents the cosine similarity between the light sensitivity sequence and the spot energy sequence, A represents the influence factor of the photocurrent on the spot shape at the current moment, and B represents the spot displacement deviation index at the current moment.

[0072] Among them, A reflects the comprehensive influence of the photocurrent on the change of the spot shape. The larger the value of A, the more significant the influence of the photocurrent on the change of the spot shape, which means the stronger the non-uniformity of the spot distribution on the detector, the greater the variability of the photocurrent, resulting in an increase in the instability of the spot positioning, and the value of B increases accordingly; c measures the similarity degree of the trends of the two sequences. When the value of c is closer to 1 or -1, it indicates that the trends of the light sensitivity sequence and the spot energy sequence are more similar or opposite, that is, the change of the spot energy is more correlated with the change of the light sensitivity. The larger its absolute value, the larger the value of B, indicating the greater the spot displacement deviation; f i and f jThe larger the absolute value of the difference is, the larger the B value is, indicating that the deviation of the spot displacement is larger.

[0073] The larger the B value is, it indicates that when the spot generates displacement, the detected deviation of the spot displacement is larger, that is, the detection accuracy is less accurate, meaning that the deviation between the actual position of the spot and the position detected by the detector is larger, thus affecting the accuracy of the spot positioning.

[0074] Thus, the spot displacement deviation index at the current moment is obtained.

[0075] Step S004, calculate the misalignment of the spot center through the spot energy, and calibrate it based on the spot displacement deviation index to obtain the misalignment of the spot center after calibration.

[0076] Use a quadrant detector to measure the offsets of the spot in the x and y directions. The quadrant detector divides the spot into four regions, and the spot energy in each region is E 1 , E 2 , E 3 , E 4 , where the spot energy refers to the optical power received by the spot in each quadrant. Since the photocurrent is proportional to the incident optical power, in this embodiment, the energy distribution of the spot in each quadrant is directly reflected by the photocurrent.

[0077] Based on the measured spot energies in the four quadrants, calculate the offset of the spot center, and its expression is:

[0078] E 1 , E 2 , E 3 , E 4 are the spot energies in the first quadrant, the second quadrant, the third quadrant, and the fourth quadrant respectively, and σ x represents the offset of the spot center in the x direction, and σ y represents the offset of the spot center in the y direction. Where a positive offset value indicates that the spot center deviates in the positive direction, and a negative offset value indicates that the spot center deviates in the negative direction.

[0079] Based on the offsets of the spot center in different directions, calculate the misalignment of the spot center. The specific calculation method is to take the square root of the sum of the squares of the two offsets of the spot center, and the expression is:

[0080] σ x represents the offset of the spot center in the x direction, and σ y represents the offset of the spot center in the y direction, and Δ represents the misalignment of the spot center.

[0081] Among them, the misalignment amount of the light spot center describes the offset distance between the light spot center and the receiver center. This offset distance directly reflects the displacement of the light spot relative to the receiver center. Therefore, it can be regarded as the displacement deviation of the light spot.

[0082] When the light spot generates displacement, the light spot intensity will affect the detector's reception of the total energy of the light spot, thereby affecting the accuracy of light spot positioning. When the light spot intensity is weak, the measurement error decreases rapidly with the increase of the light spot intensity. However, when the light spot intensity increases to a certain extent, the measurement error gradually stabilizes. At this time, increasing the light spot intensity cannot significantly improve the positioning accuracy. Moreover, there is a direct influence between the collected photocurrent and photosensitivity and the light spot intensity. Therefore, based on the calculated light spot displacement deviation index B, the misalignment amount Δ of the calculated light spot center is calibrated. The calibration method is as follows:

[0083] Δ′ = 2tanh(B)×Δ, where Δ represents the misalignment amount of the light spot center, B represents the light spot displacement deviation index at the current moment, tanh() represents the hyperbolic tangent function, and Δ′ represents the misalignment amount of the light spot center after calibration; this makes the misalignment amount after calibration smoother, reduces the occurrence of extreme values, and improves the stability and accuracy of positioning.

[0084] Since the change in the light spot intensity characterized by the photocurrent and photosensitivity will affect the detector's reception of the total energy of the light spot, thereby affecting the accuracy of light spot positioning. Calibrating the misalignment amount in this way takes into account the influence of the light spot displacement deviation index on the misalignment amount, enabling the calibration result to more accurately reflect the actual position of the light spot, thereby improving the accuracy of light spot positioning.

[0085] So far, the misalignment amount of the light spot center after calibration has been obtained.

[0086] Step S005: Based on this, obtain the light spot areas in four quadrants to achieve light spot positioning.

[0087] Calculate the light spot radius on the receiver plane and the width of the intersection area between the receiver and the spot through existing methods according to the missile target position and the seeker focal length, and calculate the intersection area between the light spot and the receiver based on the light spot radius and the width of the intersection area between the receiver and the spot through existing methods. Classify and discuss various situations of the relative position between the light spot and the receiver based on the misalignment amount of the light spot center after calibration to obtain the light spot areas in four quadrants. Finally, use the calculated light spot areas for simulation calculation to simulate the actual distribution of the light spot on the receiver, thereby achieving accurate light spot positioning.

[0088] It should be noted that the above-described embodiments are only used to illustrate the technical solutions of the present application, rather than limiting them; although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the various embodiments of the present application, and should all be included within the protection scope of the present application.

[0089] The various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referred to each other. The key point of each embodiment is to illustrate the differences from other embodiments.

Claims

1. A method for spot positioning of a four-quadrant detector of a laser seeker, characterized in that: The method comprises the following steps: The photocurrents in different quadrants are collected based on the four-quadrant detector and its ammeter to form a photocurrent matrix, and the light sensitivity is calculated based on the photocurrent and the absolute power of the collected incident light to form a light sensitivity sequence; The sum of the photocurrents of the four quadrants is sorted by time to obtain a light spot energy sequence; the elements in the photocurrent matrix are clustered to obtain several clusters, and the light spot energy sequence is extracted based on the time corresponding to the cluster to obtain the local light spot energy sequence corresponding to each cluster; the influence factor of the photocurrent at the current moment on the light spot shape is obtained according to the slope of the local light spot energy sequence after fitting, the standard deviation of the number of all row elements in each cluster, and the number of clusters; The p value and z value of each sequence are obtained by the Mann-Kendal l test algorithm for the light sensitivity sequence and the light spot energy sequence, and the trend function of the sequence is calculated according to the p value and z value of each sequence; the light spot displacement deviation index at the current moment is obtained according to the trend function difference between the light sensitivity sequence and the light spot energy sequence, the cosine similarity between the light sensitivity sequence and the light spot energy sequence, and the influence factor of the photocurrent at the current moment on the light spot shape; Calculating the offset of the center of the light spot in different directions based on the light spot energy of each quadrant; and calculating the misalignment of the center of the light spot based on the offset in different directions; calibrating the misalignment of the center of the light spot by the light spot displacement deviation index at the current moment to obtain the misalignment of the center of the light spot after calibration, wherein the light spot energy of each quadrant corresponds to the photocurrent of each quadrant; The spot area of ​​the four quadrants is obtained by the misalignment after the spot center is calibrated, so as to realize the spot positioning.

2. A method for spot positioning of a four-quadrant detector of a laser seeker as claimed in claim 1, characterized in that: The method for collecting photocurrents in different quadrants to form a photocurrent matrix based on a four-quadrant detector and an ammeter thereof is: Each quadrant is taken as each row, each acquisition moment is taken as each column, the data collected in a preset time period before the current moment is counted, and the photocurrents collected in all quadrants in this preset time period are constructed into a photocurrent matrix.

3. The method for spot positioning of a four-quadrant detector of a laser seeker as claimed in claim 1, characterized in that: The method for calculating the light sensitivity based on the photocurrent and the absolute power of the collected incident light to form a light sensitivity sequence is: The sum of the photocurrents of all quadrants is taken as the total quadrant current, and the ratio of the total quadrant current to the absolute power of the incident light is taken as the photosensitivity at each acquisition moment; The light sensitivities within the preset time period are sorted in ascending order according to time sequence to obtain a light sensitivity sequence.

4. A method for spot positioning of a four-quadrant detector of a laser seeker as claimed in claim 1, characterized in that: The method of extracting the spot energy sequence based on the time corresponding to the cluster to obtain the local spot energy sequence corresponding to each cluster is: Each row in each cluster corresponds to a start time and an end time. The earliest start time and the latest end time in each cluster are extracted, and the data of the spot energy sequence in this time period is used as the local spot energy sequence of this cluster.

5. A method for spot positioning of a four-quadrant detector of a laser seeker as claimed in claim 4, characterized in that: The method for obtaining the influence factor of the photocurrent on the spot shape at the current moment according to the slope of the local spot energy sequence after fitting, the standard deviation of the number of all row elements in each cluster, and the number of clusters is: For each cluster, count the number of elements in each row of the cluster, calculate the standard deviation of the number of all row elements, and use the standard deviation as the error weight of the cluster; Fitting each local spot energy sequence to obtain its slope, and using the slope as the response sensitivity of the cluster; The influence factor of the photocurrent on the spot shape at the current moment is calculated based on the response sensitivity and error weight of all clusters and the number of clusters; The influencing factors are positively correlated with the response sensitivity of the clusters and the error weight of the clusters.

6. The method for spot positioning of a four-quadrant detector of a laser seeker as claimed in claim 1, characterized in that: The expression of the influence factor of the photocurrent at the current moment on the spot shape is: a n represents the error weight of the nth cluster, b n represents the response sensitivity of the nth cluster, N represents the number of clusters, and A represents the influence factor of the photocurrent on the spot shape at the current moment.

7. The method for spot positioning of a four-quadrant detector of a laser seeker as claimed in claim 1, characterized in that: The method for calculating the trend function of a sequence according to the p value and z value of each sequence is: f x =z x ×g x , p x represents the p value of sequence x, g x represents the judgment function of sequence x, z x represents the z value of sequence x, f x Represents the trend function of the sequence x.

8. The method for spot positioning of a four-quadrant detector of a laser seeker as claimed in claim 1, characterized in that: The method for obtaining the spot displacement deviation index at the current moment according to the trend function difference between the light sensitivity sequence and the spot energy sequence, the cosine similarity between the light sensitivity sequence and the spot energy sequence, and the influence factor of the photocurrent at the current moment on the spot shape is: The spot displacement deviation index at the current moment is positively correlated with the trend function difference between the light sensitivity sequence and the spot energy sequence, the cosine similarity between the light sensitivity sequence and the spot energy sequence, and the influencing factor of the photocurrent on the spot shape at the current moment.

9. The method for spot positioning of a four-quadrant detector of a laser seeker as claimed in claim 1, characterized in that: The method of calculating the offset of the center of the light spot in different directions based on the light spot energy of each quadrant; and calculating the misalignment of the center of the light spot based on the offset in different directions is: E1, E2, E3, and E4 are the spot energies in the first, second, third, and fourth quadrants, respectively. x Indicates the offset of the center of the light spot in the x direction, σ y Indicates the offset of the center of the light spot in the y direction; The square root of the sum of the offsets of the center of the light spot in the x-direction and the y-direction is calculated as the misalignment of the center of the light spot.

10. The method for spot positioning of a four-quadrant detector of a laser seeker according to claim 1, characterized in that: The method of calibrating the misalignment of the light spot center by the light spot displacement deviation index at the current moment to obtain the misalignment of the light spot center after calibration is: Δ′=2tanh(B)×Δ, Δ represents the misalignment of the spot center, B represents the spot displacement deviation index at the current moment, tanh() represents the hyperbolic tangent function, and Δ′ represents the misalignment of the spot center after calibration.

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