A video small satellite target tracking field of view partition anti-miss control method and system

Abstract

This invention discloses a method and system for preventing target miss during target tracking in video microsatellites by dividing the field of view into regions I and II outside the inscribed circle. The method includes: S101, dividing the camera's field of view into an inscribed circle region I and an area II outside the inscribed circle based on the inscribed circle; S102, determining the region where the target falls within the camera's field of view, and employing a quasi-Eulerian-based anti-miss tracking control when the target falls within region II outside the inscribed circle, so that the satellite adjusts its attitude and moves rapidly towards the center of the field of view. This invention, by dividing the camera's field of view into a potential function control region and a quasi-Eulerian rotation control region, ensures that the target is always within the field of view. This solves the problems of existing video microsatellites using position information-based target tracking methods, which require prior target position information, are only applicable to cooperative target tracking, and cannot be applied to non-cooperative target tracking such as space debris.

Description

Technical Field

[0001] This invention relates to the field of video small satellite target tracking and control technology, specifically to a video small satellite target tracking field-of-view partitioning anti-miss-target control method and system. Background Technology

[0002] Video microsatellites, with their unique advantages such as short development cycles, fast response speeds, and high-resolution real-time continuous imaging, have wide applications in ground target observation (e.g., disaster monitoring, resource surveys, moving target surveillance) and space target observation. Typical video microsatellites include the LAPAN-TUBSAT, Sumbandia, and TianTuo-2 satellites. These satellites achieve continuous target tracking and video imaging by adjusting their attitude in real time to keep the target within the onboard camera's field of view. Typically, video microsatellites use position-based methods for target tracking. They calculate the video satellite's attitude and angular velocity errors using the target's position information, then control the actuators to achieve satellite attitude maneuvers and staring tracking. This method requires prior target position information and is therefore only suitable for cooperative target tracking. However, many space targets, such as space debris and malfunctioning spacecraft, are non-cooperative targets, and their real-time position information cannot be accurately obtained, making position-based methods unsuitable for tracking. Image-based space target tracking methods use the real-time deviation of the target's projection in the image plane as control feedback, eliminating the need for prior target position information. Visual servo control using camera images has wide applications in robotics, drones, and other fields. However, existing technologies do not address how to ensure that the target remains within the field of view. When the target first enters the field of view, it may leave the camera's field of view, leading to tracking failure. Summary of the Invention

[0003] The technical problem to be solved by this invention is to provide a video microsatellite target tracking field-of-view partitioning anti-miss-target control method and system, which addresses the above-mentioned problems of the prior art. This invention divides the camera's field of view into a potential function control region and a quasi-Euler rotation control region to ensure that the target is always within the field of view. This solves the problems of existing video microsatellites using position information-based target tracking methods, which require obtaining prior target position information, are only applicable to cooperative target tracking, and cannot be applied to non-cooperative target tracking such as space debris.

[0004] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0005] A method for preventing target miss during video microsatellite target tracking by dividing the field of view into zones includes:

[0006] S101, based on the inscribed circle of the camera's field of view, the camera's field of view is divided into an inscribed circle region I and a region outside the inscribed circle II;

[0007] S102, determine the area where the target falls within the camera's field of view. When the target falls within area II outside the inscribed circle, use anti-miss tracking control based on the quasi-Eulerian method to enable the satellite to adjust its attitude and move quickly toward the center of the field of view. When the target falls within area I of the inscribed circle, use anti-miss tracking control based on the potential function to prevent the target from leaving the field of view.

[0008] Optionally, the functional expression for the target-avoidance tracking control based on the quasi-Euler method is:

[0009] T c =-k p q ev -k d (ω ea +dω eb1 +ω eb2 ),

[0010] In the above formula, T c For attitude control torque, k p k d q is a control parameter where d is greater than 1. ev For the error quaternion q e The vector part, ω ea Angular velocity deviation ω e For the portion parallel to the Euler axis, d is a constant greater than 1, and ω eb1 Angular velocity deviation ω e The portion perpendicular to the Euler axis that is parallel to the image plane, ω eb2 Angular velocity deviation ω e The portion perpendicular to the Euler axis that is perpendicular to the image plane.

[0011] Optionally, angular velocity deviation ω e The portion ω parallel to the Euler axis ea The expression for the computation function is:

[0012] ω ea =aa T ω e ,

[0013] In the above formula, 'a' represents the Euler axis vector in the camera coordinate system, the superscript 'T' indicates the transpose operation, and 'r' represents the Euler axis vector. o It is the direction vector.

[0014] Optionally, angular velocity deviation ω e The portion perpendicular to the Euler axis and parallel to the image plane, ω eb1 And the portion ω perpendicular to the image plane eb2 The expression for the computation function is:

[0015]

[0016] In the above formula, I 3×3 Let r represent a third-order identity matrix. o The direction vector is ω, where the superscript T indicates the transpose operation. eb Angular velocity deviation ω e The portion perpendicular to the Euler axis.

[0017] Optionally, angular velocity deviation ω e The portion ω perpendicular to the Euler axis eb The expression for the computation function is:

[0018] ω eb =(I 3×3 -aa T )ω e ,

[0019] In the above formula, I 3×3 Let denote the third-order identity matrix, where a is the Euler axis vector in the camera coordinate system, and the superscript T indicates the transpose operation.

[0020] Optionally, step S102 may further include employing potential function-based anti-miss tracking control to prevent the target from leaving the field of view when the target falls within the inscribed circle region I.

[0021] Optionally, the functional expression for the target-avoidance tracking control based on the potential function in step S102 is:

[0022]

[0023] In the above formula, T c For attitude control torque, k c ω is the positive term gain constant. e The deviation is the angular velocity; vec represents the vector component. This represents the quaternion conjugate of the first-order gradient matrix of the potential function V, where ω is the angular velocity. For vector multiplication, q e Let J be the attitude error quaternion, and J be the rotational inertia matrix of the video microsatellite. For ω d The derivative of ω d Let A(q) be the desired attitude quaternion, where × in the superscript denotes a skew-symmetric matrix. e Let be an intermediate variable, and we have:

[0024]

[0025] In the above formula, q ev For the error quaternion q e The vector part.

[0026] Optionally, the functional expression of the potential function V is:

[0027]

[0028] In the above formula, V(q) e ) represents the attitude error quaternion q e Potential function V, k v κ and q are control parameters. e0 For the error quaternion q e The scalar part, θ max This refers to the maximum permissible angle between the optical axis and the target pointing direction under satellite anti-missing control.

[0029] Optionally, the calculation function expression for the maximum allowable angle between the optical axis and the target pointing under the satellite anti-miss control is:

[0030]

[0031] In the above formula, u s and v s Let x and y represent the x and y coordinates of the pixel plane, respectively. d is a constant greater than 1, u and v are the coordinates of the target point in the pixel coordinate system, and f is the focal length.

[0032] In addition, the present invention provides a video small satellite target tracking field of view partitioning anti-miss control system, including a microprocessor and a memory interconnected, wherein the microprocessor is programmed or configured to execute the video small satellite target tracking field of view partitioning anti-miss control method.

[0033] Furthermore, the present invention also provides a computer-readable storage medium storing a computer program, the computer program being programmed or configured by a microprocessor to execute the video microsatellite target tracking field-of-view partitioning anti-miss-target control method.

[0034] Compared with the prior art, the beneficial effects of the technical solution of the present invention are mainly reflected in the following aspects:

[0035] Firstly, this invention has a stronger ability to adjust the target to the tangent circle area within the field of view and achieve target tracking.

[0036] Secondly, when the target falls within region II outside the inscribed circle, the present invention employs anti-miss tracking control based on the quasi-Eulerian method to enable the satellite to adjust its attitude and move rapidly toward the center of the field of view. This ensures that the target remains within the inscribed circle after adjusting and entering the field of view, effectively preventing misses.

[0037] Thirdly, the present invention also includes a potential function-based anti-miss tracking control to prevent the target from leaving the field of view when the target falls within the inscribed circle region I. The field of view partitioning control method, which combines the quasi-Euler rotation method and the potential function method for the inscribed circle region I and the region outside the inscribed circle II, can ensure the continuous tracking of the target by the video microsatellite. Moreover, it has better anti-miss performance than the single PD controller method when the observed target and the video microsatellite have a large relative velocity. Attached Figure Description

[0038] Figure 1 This is a schematic diagram of the basic process of the method in an embodiment of the present invention.

[0039] Figure 2 This is a schematic diagram of the coordinate system in an embodiment of the present invention.

[0040] Figure 3 This is a schematic diagram of camera perspective projection in an embodiment of the present invention.

[0041] Figure 4 This is a camera imaging model in an embodiment of the present invention.

[0042] Figure 5 This is a schematic diagram of attitude error solving in an embodiment of the present invention.

[0043] Figure 6 This is a schematic diagram of the camera field of view partitioning in an embodiment of the present invention.

[0044] Figure 7 This is a schematic diagram of error angular velocity decomposition in an embodiment of the present invention.

[0045] Figure 8 This is a curve showing the change in the target projected pixel coordinates under the action of the PD controller in an embodiment of the present invention.

[0046] Figure 9 This is the image plane target projection trajectory under the action of the PD controller in an embodiment of the present invention.

[0047] Figure 10 This is a curve showing the change in the target projected pixel coordinates under the action of the pseudo-Euler rotation controller in an embodiment of the present invention.

[0048] Figure 11 This is the projection trajectory of the image plane target under the action of the pseudo-Euler rotation controller in an embodiment of the present invention.

[0049] Figure 12 This is a curve showing the change in the target projected pixel coordinates under the action of the pseudo-Euler rotation controller in an embodiment of the present invention.

[0050] Figure 13 This is the projection trajectory of the image plane target under the action of the pseudo-Euler rotation controller in an embodiment of the present invention.

[0051] Figure 14 This is a curve showing the change in the target projected pixel coordinates under the action of the partition controller in an embodiment of the present invention.

[0052] Figure 15 This is the image plane target projection trajectory under the action of the partition controller in this embodiment of the invention. Detailed Implementation

[0053] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0054] like Figure 1 As shown, the video microsatellite target tracking field-of-view partitioning anti-miss-target control method in this embodiment includes:

[0055] S101, based on the inscribed circle of the camera's field of view, the camera's field of view is divided into an inscribed circle region I and a region outside the inscribed circle II;

[0056] S102, determine the area where the target falls within the camera's field of view. When the target falls within area II outside the inscribed circle, use anti-miss tracking control based on the quasi-Eulerian method to enable the satellite to adjust its attitude and move quickly toward the center of the field of view. When the target falls within area I of the inscribed circle, use anti-miss tracking control based on the potential function to prevent the target from leaving the field of view.

[0057] like Figure 2 As shown, the following four coordinate systems are established in this embodiment: (1) Geocentric inertial coordinate system O i -X i Y i Z i Select the J2000.0 coordinate system, with the origin O. i Located at the Earth's core, O i X i Pointing to the vernal equinox at J2000.0, O i Z i The axis points to the pole of the J2000.0 level equator, O i Y i Axis and O i X i Shaft and O i Z i The axes form a right-handed coordinate system. (2) Satellite body coordinate system O b -X b Y b Z b Origin of coordinate system bLocated at the satellite's center of mass, the three coordinate axes are along the three directions of the satellite's principal axis of inertia. (3) Pixel coordinate system O'-uv: The origin O' of the coordinate system is located at the upper left corner of the image plane. The O'u axis and O'v axis are parallel to the row and column of the image plane, respectively, and the coordinate unit is pixels. (4) Camera coordinate system O c -X c Y c Z c Origin of coordinate system c Located at the camera's optical center, O c Z c The axis direction coincides with the camera's optical axis and points perpendicularly to the camera's image plane. Without loss of generality, this paper assumes that the camera coordinate system coincides with the satellite's body coordinate system, and that the torque output direction of the satellite attitude actuator (usually a flywheel) coincides with the satellite's body coordinate axis. c X c Shaft and O c Y c The axes are parallel to and in the same direction as the O'u and O'v axes in the pixel coordinate system, respectively, such as... Figure 3 As shown.

[0058] make i r T =( i r x , i r y , i r z ) T Let the coordinates of the spatial target in the inertial coordinate system be, such as Figure 3 As shown, based on the principle of pinhole imaging perspective projection, the camera projection model of the target point's projection onto the image plane can be represented as:

[0059]

[0060] In the above formula, f is the camera focal length, and the coordinates of the pixel where the camera optical axis intersects the image plane are (u0 v0). T , usually the center position of the image plane; du and dv are the pixel size along the O'u axis and O'v axis, respectively; This represents the direction cosine matrix from the geocentric inertial frame to the satellite body coordinate system; i r s This indicates the satellite's coordinates in the geocentric inertial frame. i r iT Represents the coordinates of the observed target in the geocentric inertial frame, such as Figure 4 As shown; Π is the camera's internal parameter matrix; T is the homogeneous transformation matrix of the satellite's body coordinate system relative to the inertial coordinate system, which is related to the satellite's position and attitude; M is the projection mapping matrix from the spatial target point to the image plane, which is jointly determined by the video microsatellite's attitude and camera parameters.

[0061] remember Let the i-th row vector of matrix M be the camera projection model (1), which can be rewritten as:

[0062]

[0063]

[0064] The kinematic equations for the attitude of a video microsatellite, described using quaternions, are as follows:

[0065]

[0066] In the above formula, q = [q0 q] v ] T Let ω be the attitude quaternion of the video microsatellite, and ω be the angular velocity of the satellite's body coordinate system relative to the geocentric inertial frame in the satellite's body coordinate system; (symbol) This represents quaternion vector multiplication; the superscript "." on a variable indicates its time derivative. After decomposing q, equation (4) can be rewritten as:

[0067]

[0068] In the above formula, I 3×3 represents a third-order identity matrix; the superscript "×" indicates a skew-symmetric matrix.

[0069] Assuming the video microsatellite is a rigid body, the attitude dynamics equations are:

[0070]

[0071] In the above formula, J is the rotational inertia matrix of the video microsatellite; T c This is the attitude control torque.

[0072] like Figure 5 As shown, the target position direction vector in the camera coordinate system is represented as... c r cT :

[0073] c r cT =(x pt ,y pt f) T (7)

[0074] In the above formula, x pt and y pt These represent the target center projection point in the camera coordinate system, O and O respectively. c X c Shaft and O c Y c The coordinates of the axes can be represented as:

[0075]

[0076] In the above formula, u and v are the coordinates of the target point in the pixel coordinate system.

[0077] The direction vector of the camera optical axis in the camera coordinate system c r o Represented as:

[0078] c r o =(0,0,1) T (9)

[0079] Attitude error is the direction vector of the target position in the camera coordinate system. c r t Vector to camera optical axis c r o The rotation angle. The attitude error quaternion q of the video microsatellite. e It can be represented as:

[0080]

[0081] In the above formula, 'a' is the Euler axis vector in the camera coordinate system, and θ is the Euler angle. Both can be derived from... c r t and c r o express.

[0082]

[0083]

[0084] The attitude quaternion q of the video microsatellite can be obtained from the onboard sensor, and combined with the attitude error quaternion q in equation (10). e The desired satellite attitude quaternion q can be obtained. d for:

[0085]

[0086]

[0087] In the formula, This can be achieved by considering the expected quaternion q. d The difference is obtained as Ξ(q) d It has the following definition:

[0088]

[0089] In the above formula, q d0 and q d1 q d2 qd3 Let q represent the desired attitude quaternion respectively. d The three elements of a scalar and a vector.

[0090] Angular velocity deviation ω e Defined as:

[0091]

[0092] When a target falls within the field of view of a video microsatellite camera, the video microsatellite obtains the target's position in the image plane through information processing as a control feedback quantity. However, the camera's field of view is finite; if the target leaves the camera's field of view (missing the target), tracking will fail. To address this problem, this embodiment designs a field-of-view partitioning-based anti-miss-the-target control method. The main idea of ​​this method is to divide the camera's field of view into two parts through an inscribed circle, such as... Figure 6 As shown, the rectangular portion is the camera image plane. The inscribed circle of the rectangle is taken as the range of action of the potential function (Region I). When the target falls within Region I, it is strictly guaranteed to remain within this range. The imaging plane outside the inscribed circle is the range of action of the quasi-Euler method (Region II). When the target falls within Region II, the satellite adjusts its attitude and moves rapidly towards the center of the field of view. Target miss control is achieved by combining two types of miss control methods, and Barbalat's lemma is used to prove that the control law is asymptotically stable within its respective region of action.

[0093] The purpose of the potential function design is to ensure that the target remains within the field of view and maintains continuous visual tracking after entering the circular projection position constraint region. When the target image is located at the boundary of the constraint region, the target position direction vector in the camera coordinate system is r. b r b With optical axis vector c r o The included angle is θ max This is the maximum permissible angle between the optical axis and the target pointing direction under satellite anti-miss control. From geometric relationships, we get:

[0094]

[0095] In the above formula, u s and v s Let x and y represent the x and y coordinates of the pixel plane, respectively. Therefore, the Euler angle θ obtained from equation (17) should satisfy:

[0096] 0≤θ<θ max (18)

[0097] In the above formula, θ max It is a quantity that is no greater than the camera's field of view, therefore we can obtain:

[0098]

[0099] When the target projection satisfies the constraint condition, i.e., the imaging position is within the restricted area, the set of error quaternions Q is... e satisfy:

[0100]

[0101] Based on the inequality relationship expressed by equation (20), a method is constructed using the error quaternion q. e The logarithmic potential function described:

[0102]

[0103] In the above formula, k v Let κ be a positive term constant and satisfy:

[0104]

[0105] It is evenly distributed between 0 and 1.

[0106] Based on the error quaternion q e By definition, equation (21) above can be rewritten as:

[0107]

[0108] As can be seen from equation (22), the potential function value is determined by the error quaternion q. e scalar part q e0 Decision, or alternative definition:

[0109]

[0110] Then V(q) e ) = V f (q e0 ), V f For q e0 Perform differentiation

[0111]

[0112] That is, q e ∈Q e hour, And 1-q e0 >0、 so With q e0 V tends towards the maximum value of 1. f The value is monotonically decreasing, i.e., V(q) e The value is monotonically decreasing. When When, 1-q e0 =0 and It equals a definite real constant, so V(q) e ) = 0; when qe ∈Q e And q e ≠(1 0) T At that time, V(q) e )>0, and when the projected position approaches the boundary of the restricted range, θ→θ max ,at this time Therefore, the potential function will approach infinity.

[0113] The functional expression for the anti-miss tracking control based on the potential function in step S102 of this embodiment is as follows:

[0114]

[0115] In the above formula, T c For attitude control torque, k c ω is the positive term gain constant. e The deviation is the angular velocity; vec represents the vector component. This represents the quaternion conjugate of the first-order gradient matrix of the potential function V, where ω is the angular velocity. For vector multiplication, q e Let J be the attitude error quaternion, and J be the rotational inertia matrix of the video microsatellite. For ω d The derivative of ω d Let A(q) be the desired attitude quaternion, where × in the superscript denotes a skew-symmetric matrix. e Let be an intermediate variable, and we have:

[0116]

[0117] In the above formula, q ev For the error quaternion q e The vector part. In this embodiment, the functional expression of the potential function V is:

[0118]

[0119] In the above formula, V(q) e ) represents the attitude error quaternion q e Potential function V, k v κ and q are control parameters. e0 For the error quaternion q e The scalar part, θ max This represents the maximum permissible angle between the optical axis and the target pointing direction under satellite anti-miss control. The calculation function expression for the maximum permissible angle between the optical axis and the target pointing direction under satellite anti-miss control in this embodiment is:

[0120]

[0121] In the above formula, u s and vs Let x and y represent the x and y coordinates of the pixel plane, respectively. d is a constant greater than 1, u and v are the coordinates of the target point in the pixel coordinate system, and f is the focal length.

[0122] To analyze the stability of the controller shown in equation (25), an augmented function V is constructed. t as follows:

[0123]

[0124] Obviously V t ≥0. For V t Differentiation yields:

[0125]

[0126] In the formula, vec(·) represents the vector part of (·), and the superscript * indicates quaternion conjugation. The first-order gradient matrix of the potential function V is expressed as:

[0127]

[0128] Substituting control laws (25) and (28) into equation (27), we get:

[0129]

[0130] Therefore, Vt is monotonically decreasing. Since Vt≥0, we have 0≤Vt. t ≤V t (0), meaning Vt is bounded. Take the second derivative of Vt with respect to time:

[0131]

[0132] Due to V t It is bounded, therefore we can obtain q e and ω e All are bounded. Due to the boundedness of the above variables, it is possible to determine... It is also bounded. According to Barbalat's lemma, we have:

[0133]

[0134] Right now Combining the control law (25), the attitude dynamics equation (6), and equation (16):

[0135]

[0136] according to Easy to obtain Therefore, from equation (32), we can obtain Combining the expression shown in equation (28), we can obtain This indicates that the closed-loop system is asymptotically stable.

[0137] It is worth noting that, assuming the actuator (flywheel) does not reach its maximum output torque during the control process, the tracking control method based on the potential function can rigorously prove that the target will always remain within region I when it falls within region I. If the relative angular velocity between the satellite and the target is too large, causing the actuator output to saturate, the target may still leave region I. As can be seen from the definition of the potential function expression (25) designed in the previous section, this potential function is only effective when the target initially falls within the circular projection area. However, the target's projection may not initially be within the circular projection area (region I). In this case, the target may not have missed the target, and the camera can still capture the target and obtain position information. In region II, it is necessary to quickly adjust the target towards the center of the field of view to avoid the target moving away from the center of the field of view and thus missing the target.

[0138] According to equation (11) for solving the Euler axis, the Euler axis is perpendicular to the camera optical axis, and the camera optical axis is perpendicular to the image plane. Therefore, the Euler axis is parallel to the image plane. The error angular velocity ω can be... e It can be decomposed into two parts, one parallel to the Euler axis and the other perpendicular to the Euler axis, denoted as ω. ea and ω eb ,like Figure 7 As shown. And ω eb It can also be decomposed into parts parallel and perpendicular to the image plane, denoted as ω. eb1 and ω eb2 The expressions for the above angular velocities are as follows:

[0139]

[0140] In the above formula, 'a' represents the Euler axis vector in the camera coordinate system, the superscript 'T' indicates the transpose operation, and 'r' represents the Euler axis vector. o I is the direction vector. 3×3 Let ω represent the third-order identity matrix. eb Angular velocity deviation ω e The portion perpendicular to the Euler axis, I 3×3 Let denote the third-order identity matrix, and a be the Euler axis vector in the camera coordinate system.

[0141] Among them, the component parallel to the Euler axis ω ea and the component ω perpendicular to the Euler axis and perpendicular to the image plane eb2 It will not cause optical axis pointing deviation; only the component ω perpendicular to the Euler axis and parallel to the image plane exists. eb2 This can cause the target's projected trajectory to deflect laterally, potentially leading to a miss. To quickly adjust the target towards the center of the field of view and eliminate the error angular velocity component ω that causes lateral deflection, [further measures are needed]. eb2Due to the influence of this, the functional expression for the anti-miss tracking control based on the quasi-Euler method in this embodiment is as follows:

[0142]

[0143] In the above formula, T c For attitude control torque, k p k d q is a control parameter where d is greater than 1. ev For the error quaternion q e The vector part, ω ea Angular velocity deviation ω e For the portion parallel to the Euler axis, d is a constant greater than 1, and ω eb1 Angular velocity deviation ω e The portion perpendicular to the Euler axis that is parallel to the image plane, ω eb2 Angular velocity deviation ω e The portion perpendicular to the Euler axis that is perpendicular to the image plane. Here, d>1 is a constant.

[0144] make Then we have:

[0145]

[0146] Since d > 1, and Both are positive semi-definite, therefore K t It is a positive definite matrix. According to Barbalat's lemma, the closed-loop system is asymptotically stable.

[0147] In summary, the controllers based on potential functions and quasi-Euler rotations in this embodiment are asymptotically stable within their respective regions of operation. The specific form of the control law used is as follows:

[0148]

[0149] In the formula, P represents the projected position of the target on the image plane.

[0150] The orbital parameters and camera parameters of the video microsatellite and the space target set in the simulation of this embodiment are shown in Tables 1 and 2, respectively. The initial attitude quaternion of the video microsatellite is (0.2808, 0.9042, 0.3216, 0.0146). T .

[0151] Table 1 Orbit parameters of video microsatellites and observation space targets

[0152] Video microsatellites Parameter value Space Targets Parameter value semi-long shaft 6878.14km semi-long shaft 6863.14km Eccentricity 8.44×10-8 Eccentricity 9.99×10-8 track inclination 45° track inclination 45° Right ascension of ascending node 156.65° Right ascension of ascending node 146.64° Perimeter Argument 264.23° Perimeter Argument 274.63° True near point angle 219.12° True near point angle 218.58°

[0153] Table 2. Parameters of Spaceborne Cameras

[0154] parameter Parameter value Focal length f 0.8m Pixel size du×dv 7μm×7μm <![CDATA[Image size u all ×v all > 3200×2900 <![CDATA[Coordinate of the pixel point at the center of the field of view (u0 v0) T > <![CDATA[(1600 1450) T ]]>

[0155] Consider using a reaction flywheel, orthogonally mounted on three axes in the satellite's body coordinate system, as the attitude control actuator. Its output control torque is limited by a maximum value, which is 0.3 N·m in the simulation. Furthermore, in this embodiment, the moment of inertia of the video microsatellite is assumed to be:

[0156]

[0157] The initial angular velocity of the video satellite was set to (-0.4, -1, 0.01) deg / s, and simulations were performed using a PD controller and a quasi-Euler rotation controller. The PD controller is a well-known method, so its implementation details are not described here. It should be noted that the simulation assumes the video satellite can acquire its relative pose to the target regardless of whether the observed object misses, and the PD controller can always receive error information and apply control. The PD controller parameters are set to k. p =6,k d =5, the parameters of the quasi-Euler rotary controller are set to k p =6,k d =5, d=4. The target's projected coordinates and trajectory on the image plane under PD control and quasi-Eulerian rotation control are as follows: Figure 8 , Figure 9 , Figure 10 and Figure 11 As shown. It can be seen that, initially, the target is located near the edge of the image plane and has a large relative angular velocity towards the edge. After moving for a period of time under the action of the PD controller, the target misses the target. Figure 9 The black dashed line at the bottom center represents the lower boundary of the imaging plane. Since it was previously assumed that the controller could always apply control regardless of whether the target missed, it was ultimately possible to control the target to the midpoint of the image plane. However, in actual operation, if the target misses, position information cannot be obtained, and tracking control will fail. Figure 11 It can be seen that the target remains within the camera plane during quasi-Euler rotation control. This is because quasi-Euler rotation control can significantly suppress lateral target drift, thus mitigating misses. Meanwhile, in comparison... Figure 8 and Figure 10 It can be seen that the quasi-Euler rotation control reaches convergence in a shorter time than the PD control. Therefore, in tracking and observation control, the quasi-Euler rotation control outperforms the PD control.

[0158] The initial angular velocity of the video satellite is set to (2.4, -2, 0.01) deg / s, which is greater than the initial angular velocity set in the previous scene. The quasi-Euler rotation controller parameter is k. p =6,k d =5, d=4, the partition controller parameter is k p =6,kd =5, d=4 and k c =8,k v =10, κ=9000. The target's projected coordinates and trajectory on the image plane under the action of the quasi-Euler rotation controller are as follows: Figure 12 and Figure 13 As shown, the target projection coordinates and trajectory under the action of the partition controller are as follows: Figure 14 and Figure 15 As shown, Figure 15 The area inside the middle circle represents the region of effect of the potential function. It can be seen that for a large initial angular velocity, the target still misses the target when only the quasi-Euler method is used for control. However, under the control of the zone controller combining the potential function and the quasi-Euler rotation method, the target never misses the target and remains within the camera's field of view. Therefore, among these three control methods, the control method combining the potential function and the quasi-Euler rotation method is the most effective in preventing the target from missing the target. Furthermore, comparing the three sets of projected pixel coordinate-time variation curves, the target reaches the image center fastest using the combined control method. Therefore, the proposed combined potential function and quasi-Euler rotation control method not only has good anti-missing capabilities in video small satellite tracking observation but also offers a faster tracking speed.

[0159] In summary, addressing the challenges of existing video microsatellite target tracking methods that rely on prior target position information and are only applicable to cooperative targets (not non-cooperative targets like space debris), and the lack of consideration for ensuring the target remains within the field of view in traditional tracking control methods, this embodiment proposes a field-of-view partitioning-based target anti-miss control method for video microsatellites. By combining potential function and quasi-Euler rotation control methods, this method achieves anti-miss control during video microsatellite tracking of space targets. By dividing the camera's field of view into a potential function control region and a quasi-Euler rotation control region, this method ensures the target remains within the field of view, effectively preventing it from slipping out of the view. Furthermore, compared to traditional PD control methods, this method offers faster convergence and better anti-miss performance. Simulation results show that both the traditional PD controller and the quasi-Euler rotation controller have the ability to adjust the target into the tangent circle region within the field of view and achieve target tracking, but the quasi-Euler rotation controller has a stronger adjustment capability; after the target is adjusted into the tangent circle within the field of view, the potential function anti-miss controller can ensure that the target remains in this region, effectively preventing the observed target from missing the target; by combining the quasi-Euler rotation method and the potential function method to achieve field of view partitioning control, continuous tracking of the target can be achieved.

[0160] Furthermore, this embodiment also provides a video small satellite target tracking field-of-view partitioning anti-miss-target control system, including a microprocessor and a memory interconnected thereto. The microprocessor is programmed or configured to execute the video small satellite target tracking field-of-view partitioning anti-miss-target control method. Additionally, this embodiment also provides a computer-readable storage medium storing a computer program for being programmed or configured by the microprocessor to execute the video small satellite target tracking field-of-view partitioning anti-miss-target control method.

[0161] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-readable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code. This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create a machine for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to operate in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The functions specified in one or more boxes. These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable apparatus for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0162] The above description is merely a preferred embodiment of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principles of the present invention should also be considered within the scope of protection of the present invention.

Claims

1. A method for preventing target miss during video small satellite target tracking by dividing the field of view into zones, characterized in that, include: S101, based on the inscribed circle of the camera's field of view, the camera's field of view is divided into an inscribed circle region I and a region outside the inscribed circle II; S102, determine the area where the target falls within the camera's field of view. When the target falls within region II outside the inscribed circle, use anti-miss tracking control based on the quasi-Eulerian method to enable the satellite to adjust its attitude and move rapidly towards the center of the field of view. When the target falls within region I of the inscribed circle, use anti-miss tracking control based on a potential function to prevent the target from leaving the field of view. The functional expression for the anti-miss tracking control based on the quasi-Eulerian method is: ， In the above formula, For attitude control torque, , and For control parameters and Greater than 1, For error quaternions The vector part, Angular velocity deviation The portion parallel to the Euler axis, Angular velocity deviation The portion perpendicular to the Euler axis that is parallel to the image plane. Angular velocity deviation The portion perpendicular to the Euler axis, specifically the portion perpendicular to the image plane; the functional expression for the target-avoidance tracking control based on the potential function is: ， In the above formula, For attitude control torque, It is the positive term gain constant. For angular velocity deviation, Indicates the vector part, Represents the potential function The quaternion conjugate of the first-order gradient matrix, Angular velocity, For vector multiplication, The attitude error quaternion, Here is the rotational inertia matrix of the video microsatellite. for The derivative of For the desired attitude quaternion, the superscript in... Represents an oblique symmetric matrix. Let be an intermediate variable, and we have: ， In the above formula, For error quaternions The vector part.

2. The video microsatellite target tracking field-of-view partitioning anti-miss-target control method according to claim 1, characterized in that, Angular velocity bias Portions parallel to the Euler axis The computational function expression is: ， In the above formula, This is the Euler axis vector in the camera coordinate system, with the superscript T indicating the transpose operation.

3. The video microsatellite target tracking field of view sector de-targeting control method according to claim 1, wherein, angular velocity deviation The portion perpendicular to the Euler axis and parallel to the image plane and the portion perpendicular to the image plane The expression for the computation function is: ， In the above formula, Represents a third-order identity matrix. The direction vector is indicated by the superscript T, which signifies the transpose operation. Angular velocity deviation The portion perpendicular to the Euler axis.

4. The video microsatellite target tracking field-of-view partition miss distance control method according to claim 3, characterized in that, Angular velocity bias Portions normal to the Euler axis The computational function expression is: ， In the above formula, Represents a third-order identity matrix. This is the Euler axis vector in the camera coordinate system, with the superscript T indicating the transpose operation.

5. The video microsatellite target tracking field-of-view partitioning anti-miss-target control method according to claim 1, characterized in that, The potential function The function expression of the potential function is: ， In the above formula, Represents the quaternion of attitude error potential function , and For control parameters, For error quaternions The scalar part, This refers to the maximum permissible angle between the optical axis and the target pointing direction under satellite anti-missing control.

6. The video microsatellite target tracking field-of-view partitioning anti-miss-target control method according to claim 5, characterized in that, The calculation function expression for the maximum allowable angle between the optical axis and the target pointing direction under the satellite anti-miss control is as follows: ， In the above formula, and These represent the horizontal and vertical coordinates of the pixel plane, respectively. For control parameters greater than 1, and The coordinates of the target point in the pixel coordinate system. It is the focal length.

7. A video microsatellite target tracking field-of-view partitioning anti-miss control system, comprising a microprocessor and a memory interconnected, characterized in that, The microprocessor is programmed or configured to execute the video microsatellite target tracking field-of-view partitioning anti-miss-target control method according to any one of claims 1 to 6.

8. A computer-readable storage medium storing a computer program, characterized in that, The computer program is used to be programmed or configured by a microprocessor to execute the video microsatellite target tracking field-of-view partitioning anti-miss-target control method according to any one of claims 1 to 6.

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