Spot positioning method for a four-quadrant detector of a laser seeker

Abstract

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. The method includes: constructing a photocurrent matrix through photocurrents, calculating the photosensitivity based on the photocurrents and the absolute power, and forming a photosensitivity sequence; sorting the photocurrents to obtain a spot energy sequence, clustering the photocurrent matrix to obtain a local spot energy sequence, and obtaining the influence factor of the current photocurrent on the spot shape based on its characteristics; analyzing the photosensitivity sequence and the spot energy sequence, and obtaining the spot displacement deviation index at the current moment according to its trend, similarity, and influence factor; calculating the misalignment amount of the spot center through the spot energy, and calibrating it based on the spot displacement deviation index to obtain the misaligned amount after calibrating the spot center; obtaining the spot areas of the four quadrants based on this, so as to achieve spot positioning. This application optimizes the accuracy of spot positioning and improves the stability of positioning.

Description

Technical Field

[0001] The present application relates to the technical field of light spot positioning of intelligent sensors, and in particular to a light spot positioning method of a four-quadrant detector of a laser seeker. Background Art

[0002] The spot positioning technology used in laser seeker four-quadrant detectors has its origins in the military, particularly in precision-guided weapon systems. The four-quadrant detector, with its unique four-segment design, precisely measures the position of the laser spot relative to the detector center. This advancement enables guidance systems to adjust flight paths in real time, ensuring precise target engagement. The significance of this technology lies in its significant enhancement of guidance system accuracy and reliability, playing a crucial role in improving combat effectiveness and reducing unnecessary damage.

[0003] In the application of laser seekers, the accuracy of light spot positioning is crucial to the hit accuracy of guided weapons. Due to the uneven distribution of light spots on the detector, the offset of the light spot center of mass and the change of light spot energy, deviations will occur in light spot positioning, affecting the strike effect of guided weapons. Specifically, the uneven distribution of light spots will cause changes in photocurrent, which in turn affects the measurement value of light sensitivity, making the light spot positioning inaccurate. In addition, the offset of the light spot center of mass will cause uneven distribution of light spots on the detector, further affecting the stability and accuracy of light spot positioning. These positioning errors not only reduce the hit rate of guided weapons, but may also 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 technical solution adopted is as follows:

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

[0006] The photocurrents in different quadrants are collected based on the four-quadrant detector and its ammeter to form a photocurrent matrix. The photosensitivity is calculated based on the photocurrent and the absolute power of the collected incident light to form a photosensitivity sequence.

[0007] 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 current photocurrent on the light spot shape is obtained based on the slope of the fitted local light spot energy sequence, the standard deviation of the number of elements in all rows of each cluster, and the number of clusters;

[0008] The Mann-Kendall test algorithm is used to obtain the p-value and z-value of each sequence for the light sensitivity sequence and the light spot energy sequence, and the trend function of the sequence is calculated based on the p-value and z-value of each sequence. The light spot displacement deviation index at the current moment is obtained based on 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 on the light spot shape at the current moment.

[0009] Calculating the offset of the light spot center in different directions based on the light spot energy of each quadrant; and calculating the misalignment of the light spot center based on the offset in different directions; calibrating the misalignment of the light spot center by using the light spot displacement deviation index at the current moment to obtain the misalignment of the light spot center after calibration, wherein the light spot energy of each quadrant corresponds to the photocurrent of each quadrant;

[0010] The spot area of the four quadrants is obtained by the offset after the spot center calibration, so as to achieve spot positioning.

[0011] In the above scheme, the present application proposes a spot positioning method for a four-quadrant detector of a laser seeker. In view of 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, thereby solving the problem of the influence of spot shape change on positioning accuracy; in view of the deviation of the detector's response degree to the light signal, the Mann-Kendall test algorithm and cosine similarity are used to reflect the spot displacement deviation, thereby eliminating the influence of uneven spot energy distribution and light sensitivity change. 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, thereby reducing the occurrence of extreme values and improving positioning stability. In addition, the actual distribution of the spot on the receiver is simulated by simulation calculation, thereby further optimizing the accuracy of spot positioning, thereby providing guided weapons with more reliable target tracking and strike capabilities.

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

[0013] Each quadrant is taken as a row and each acquisition moment is taken as a column. The data collected in the preset time period before the current moment are counted, and the photocurrents collected in all quadrants in the preset time period are constructed into a photocurrent matrix.

[0014] In one embodiment, 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:

[0015] 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;

[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 of the local spot energy sequence, the standard deviation of the number of elements in each row of each clustering cluster, and the number of clustering clusters is as follows:

[0020] 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 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 respectively. 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 A 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 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 is as follows:

[0028] The spot displacement deviation index at the current moment is positively correlated with the difference in 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.

[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] E1, E2, E3, and E4 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] Calculate the square root of the sum of the squares of the offsets of the spot center in the x direction and the y direction 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 method for locating the light spot of a four-quadrant detector of a laser seeker. Aiming at the problem of the influence of light spot energy on photocurrent, the DBSCAN density clustering algorithm is used to reflect the influence of photocurrent on the change of light spot shape, and the problem of the influence of light spot shape change on the positioning accuracy is solved. Aiming at the deviation of the detector's response degree to the optical signal, the Mann-Kendall test algorithm and cosine similarity are used to reflect the light spot displacement deviation, excluding the influence of uneven light spot energy distribution and light sensitivity change. By calibrating the misalignment amount, and by comprehensively considering the influence of light spot shape change, light spot displacement deviation and light spot intensity, the position of the light spot is effectively calibrated, the occurrence of extreme values is reduced, the stability of positioning is improved, and the actual distribution of the light spot on the receiver is simulated by combining simulation calculations, further optimizing the accuracy of light spot positioning, thereby providing more reliable target tracking and striking capabilities for guided weapons. 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 following will briefly introduce the drawings required to be used in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0037] Figure 1 It is a flowchart of a method for locating the light spot of a four-quadrant detector of a laser seeker provided by an embodiment of the present application. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0038] In order to further elaborate on the technical means and effects adopted by the present application to achieve the intended invention purpose, the following will, in combination with the accompanying drawings and preferred embodiments, describe in detail the specific implementation manner, structure, features and effects of a method for locating the light spot of a four-quadrant detector of a laser seeker proposed according to the present application. In the following description, different "one embodiment" or "another embodiment" do not necessarily refer to the same embodiment. In addition, the specific features, structures or characteristics in one or more embodiments can be combined in any suitable form.

[0039] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which this application belongs.

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

[0041] The following will specifically describe the specific solution of a method for locating the light spot of a four-quadrant detector of a laser seeker provided by the present application in combination with the accompanying drawings.

[0042] Please refer to 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, a photosensitivity sequence and a 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 I1, I2, I3, and I4 respectively. 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, I1 = I2 = I3 = I4. Therefore, the sum of the photocurrents I1 + I2 + I3 + I4, which is the total quadrant current, 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 shifts relative to the center of the detector, the illuminated areas of the quadrants will vary, resulting in different photocurrents in each quadrant. At this time, the total quadrant current still reflects the total energy of the light spot, but 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 by 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 all row elements, and use the standard deviation as the error 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 moments of each clustering cluster, extract the light spot energy sequence to reflect the response sensitivity of the photocurrent to the change in 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 on the light spot shape at the current moment based on the response sensitivities, error weights, and the number of clustering clusters of all clustering clusters.

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

[0054] It should be noted that positive correlation means that when one variable increases, the other variable also increases, and the two variables change in the same direction. 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 actual applications, 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 two variables change in opposite directions. 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 actual applications, 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 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.

[0058] Among them, a n reflects the instability of the photocurrent at different moments within the same clustering cluster. A smaller standard deviation means that the data points within the clustering 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 a, the greater the variability of the photocurrent within the clustering cluster, which means that the data in this clustering cluster is not stable enough, and the data error within this clustering 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, the more significant the change in the photocurrent caused by a small change in spot energy, 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 impact of the detector photocurrent on the change in spot shape. The larger the value of A, the more significant the impact 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 light sensitivity sequence and the spot energy sequence, and obtain the spot displacement deviation index at the current moment according to their trends, similarities, and influence factors.

[0061] The spot energy characterized by the photocurrent in each quadrant refers to the energy distribution of the spot on the detector. The light 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 light sensitivity.

[0062] The optical sensitivity reflects the response ability of the detector to optical signals. High optical sensitivity means that the detector has a stronger response to optical signals, 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. Since 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 as that there is no trend in the data and the alternative hypothesis as that the data has a trend, the p-value and z-value of the optical sensitivity sequence are output. 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, which is 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 is, 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 is (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, the p-value and z-value of the spot energy sequence are output using the same method. In addition, taking the optical sensitivity sequence and the spot energy sequence as the input, the cosine similarity between the two sequences is calculated.

[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 x represents the z-value of sequence x, f x represents the trend function of sequence x.

[0067] Among them, the trend function reflects the trend change of the sequence. The larger the z x value, the more obvious the trend of the sequence. The g x function 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 px ≥ 0.05 indicates that the trend is not significant, and at this time g x = 0. f x The larger the value of f, 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 at the current moment on the spot shape, 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 at the current moment on the spot shape.

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

[0071] B = A × |c × (f i - f j )|, 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 at the current moment on the spot shape, 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 that the distribution non-uniformity of the spot on the detector is stronger, the variability of the photocurrent is greater, 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. When its absolute value is larger, the value of B is also larger, indicating that the spot displacement deviation is larger; the absolute value of the difference between f i and f j is larger, and the value of B is also larger, indicating that the spot displacement deviation is larger.

[0073] The larger the value of B, the greater the detected spot displacement deviation when the spot generates displacement, that is, the less accurate the detection accuracy, which means 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 based on the spot energy, and calibrate it based on the spot displacement deviation index to obtain the misaligned amount after calibrating the spot center.

[0076] Measure the offsets of the spot in the x and y directions using a quadrant detector. The quadrant detector divides the spot into four regions, and the spot energies in each region are E1, E2, E3, and E4 respectively. 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] Calculate the offset of the spot center based on the measured spot energies in the four quadrants. The expression is:

[0078] E1, E2, E3, and E4 are the spot energies in the first quadrant, second quadrant, third quadrant, and 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. A positive offset value indicates that the spot center is offset in the positive direction, and a negative offset value indicates that the spot center is offset in the negative direction.

[0079] Calculate the misalignment of the spot center based on the offsets of the spot center in different directions. The specific calculation method is to take the square root of the sum of the squares of the two offsets of the spot center. 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 of the spot center describes the offset distance between the spot center and the receiver center. This offset distance directly reflects the displacement of the spot relative to the receiver center, so it can be regarded as the displacement deviation of the spot.

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

[0083] 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 misaligned amount after the spot center is calibrated; this makes the misaligned amount after calibration smoother, reduces the occurrence of extreme values, and improves the stability and accuracy of positioning.

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

[0085] Thus far, the misaligned amount after the spot center is calibrated has been obtained.

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

[0087] Calculate the 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 spot and the receiver based on the 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 positions of the spot and the receiver based on the misaligned amount after the spot center is calibrated to obtain the spot areas of the four quadrants. Finally, use the calculated spot areas for simulation calculations to simulate the actual distribution of the spot on the receiver, thereby achieving accurate 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 to limit 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] Each embodiment in this specification is described in a progressive manner, and the same or similar parts between the embodiments can be referred to each other. The key points of each embodiment are 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 includes the following steps: Based on a quadrant detector and its ammeter, the photocurrents in different quadrants are collected to form a photocurrent matrix. Based on the photocurrents and the absolute power of the incident light collected, the optical sensitivity is calculated to form an optical sensitivity sequence; The sum values of the photocurrents in the four quadrants are sorted by time to obtain a spot energy sequence; the elements in the photocurrent matrix are clustered to obtain several clustering clusters, and based on the moments corresponding to the clustering clusters, the spot energy sequence is extracted to obtain the local spot energy sequence corresponding to each clustering cluster; according to the slope after fitting of the local spot energy sequence, the standard deviation of the number of elements in each row of each clustering cluster, and the number of clustering clusters, the influence factor of the photocurrent at the current moment on the spot shape is obtained; 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 according to the p-value and z-value of each sequence; according to the difference between 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; Based on the spot energy of 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 by the spot displacement deviation index at the current moment to obtain the calibrated misalignment of the spot center, and the spot energy of each quadrant corresponds to the photocurrent of each quadrant; The spot areas of the four quadrants are obtained through the calibrated misalignment of the spot center, thereby realizing spot positioning.

2. The spot positioning method of a four-quadrant detector for a laser seeker according to claim 1, wherein The method for collecting the photocurrents in different quadrants based on a quadrant detector and its ammeter to form a photocurrent matrix is as follows: Taking each quadrant as each row and each acquisition moment as each column, the data collected in a 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.

3. The spot positioning method of a four-quadrant detector for a laser seeker according to claim 1, wherein The method for calculating the optical sensitivity based on the photocurrents and the absolute power of the incident light collected to form an optical sensitivity sequence is as follows: 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; The optical sensitivities within the preset time period are sorted in ascending order according to time to obtain an optical sensitivity sequence.

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

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

6. The spot positioning method of a four-quadrant detector for a laser seeker according to claim 1, wherein, 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 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 on the spot shape at the current moment.

7. A method for spot positioning of a four-quadrant detector of a laser seeker according to claim 1, characterized in that, The method for calculating the trend function of the 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 decision function of sequence x, z x represents the z-value of sequence x, f x represents the trend function of sequence x.

8. The spot positioning method of a four-quadrant detector for a laser seeker according to claim 1, wherein 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 influence factor of the photocurrent at the current moment on the spot shape.

9. The spot positioning method of a four-quadrant detector of a laser seeker according to claim 1, characterized in that 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: E1, E2, E3, and E4 are the spot energies in the first quadrant, second quadrant, third quadrant, and 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; Calculating the square root of the sum of the squares of the offsets of the spot center in the x direction and the y direction as the misalignment of the spot center.

10. The method for spot positioning of a four-quadrant detector of a laser seeker according to claim 1, characterized in that: 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: 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.

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