Tracking and pointing attitude maneuvering path planning method based on normal vector

Abstract

A tracking and pointing attitude maneuvering path planning method based on a normal vector belongs to the technical field of spacecraft attitude control, and comprises the following steps: at any moment in a tracking and pointing maneuvering process, setting a camera optical axis to align a target, setting a satellite body axis direction vertical to the camera optical axis according to maneuvering capability and direction requirements, the setting basis is that the body shaft is in the set normal vector direction; the set normal vector direction is determined according to the tracking and aiming task and comprises four conditions, namely data transmission protection, energy protection, maneuver protection and imaging protection. According to the method, the normal vector of the plane is formed by applying the target pointing and the ground pointing, so that the target attitude setting during antenna ground data transmission is maintained as much as possible while tracking and pointing are realized.

Description

Technical Field

[0001] The invention relates to a normal vector-based tracking and aiming attitude maneuvering path planning method, belonging to the technical field of spacecraft attitude control. Background Art

[0002] When a satellite with a flexible attachment performs attitude maneuvers, it is necessary to plan the maneuvering path. In the tracking mission, the target position changes over time, so the maneuvering path planning problem is reduced to the target attitude calculation problem at each moment. The primary constraint of the target attitude is to achieve tracking, that is, the camera optical axis is aligned with the target, and the secondary constraint is the requirements of ensuring data transmission and energy conservation.

[0003] To ensure data transmission, the angle between the antenna and the earth must be as small as possible. If the antenna is perpendicular to the camera optical axis, but the target and the earth are not perpendicular, the angle between the antenna and the earth is minimized when the antenna, the camera optical axis, and the earth are in the same plane, while ensuring tracking. To ensure energy requirements, the sunlight direction must be as close to the normal direction of the sailboard as possible, that is, perpendicular to the direction of the sailboard's rotation axis. At this time, when the sailboard normal, the camera optical axis, and the sun are in the same plane, the angle between the sunlight direction and the sailboard normal direction is as small as possible, assuming that the position of the sailboard on the main axis remains unchanged.

[0004] When the target's line of sight angular velocity is large, it is necessary to ensure that the tracking constraint is achieved first. Considering that the tracking time of a single target is much shorter than the synchronous orbit period, it can be considered that the relative path of the satellite to the target is in a plane during the tracking process. To ensure the maneuvering speed, consider making the minimum inertia axis coincide with the plane normal vector to plan the maneuvering path. When the line of sight angular velocity of the observed target is the largest, in order to increase the imaging quality, it is necessary to keep the imaging axis from rotating. Summary of the invention

[0005] The technical problem solved by the present invention is: to overcome the shortcomings of the prior art, to provide a normal vector-based tracking and aiming attitude maneuvering path planning method, and to provide normal vector selection and target attitude setting in four cases: data transmission preservation, energy preservation, maneuverability preservation, and imaging preservation: data transmission preservation means that the angle between the antenna pointing and the earth pointing direction is as small as possible, energy preservation means that the angle between the sailboard normal and the sunlight direction is as small as possible, maneuverability preservation means that the maneuverability is used as much as possible in the direction of tracking the target; imaging preservation means that the camera does not rotate around the optical axis, and only the Euler angles of the other two axes are set.

[0006] The technical solution of the present invention is: a normal vector-based tracking and aiming attitude maneuvering path planning method, at any time during the tracking and aiming maneuvering process, the camera optical axis is set to align with the target, and the satellite body axis perpendicular to the camera optical axis is set according to the maneuvering capability and pointing requirements, and the setting basis is that the body axis is in the set normal vector direction; the setting normal vector direction is determined according to the tracking and aiming task, including:

[0007] Case 1: When the maneuverability meets the mission requirements and the antenna should always communicate with the ground, the communication mode is entered. At this time, the body axis with the largest angle between the camera optical axis and the antenna is found, and its direction is set as the normal vector of the plane where the tracking direction and the ground direction are located;

[0008] Case 2: When the maneuverability meets the mission requirements and the sailboard should generate electricity all the time, the energy conservation mode is entered. At this time, the main body axis with the largest angle with the camera optical axis and the sailboard axis is selected, and its direction is set as the normal vector of the plane where the tracking direction and the sun direction are located;

[0009] Case 3: When the maneuverability can only meet the tracking and aiming requirements, the satellite enters the maneuvering mode. At this time, the body axis with the largest angle with the orbital plane is selected, and its direction is set as the normal vector of the plane where the satellite relative trajectory is located.

[0010] Case 4: When the tracking and aiming stability is required to be the highest, enter the image preservation mode. At this time, only the camera optical axis is set to point to the target, and other axes are not controlled.

[0011] Further, in the case 1, the Xr axis of the target attitude OXrYrZr points to the observed target, and Zr is the antenna direction; the plane formed by Xr and the geocentric vector is the target-geocentric plane, and Yr is the target-geocentric plane normal vector; Zr is determined by the right-hand rule, and the Yr direction ensures that the angle between Zr and the geocentric vector is not greater than 90°; the nominal attitude of the satellite at this time is conducive to data transmission between the digital transmission antenna and the ground while keeping Xr pointing to the target;

[0012] If you need to ensure data transmission between the antenna and the ground while taking into account energy or mobility, choose an angle Rotate Yr and Zr around -Xr

[0013] When the angle between the centroid vector and Xr is greater than the protection angle AngPro and less than 180-AngPro, the target pointing coordinate system is defined without singular points, and the target pointing attitude is

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[0023] in, is the representation of Xr in the inertial system, is the representation of the geocentric vector in the inertial system, It is the angle between Zr and the target-geocentric plane; Zr is positive when the projection vector of the plane is biased towards -Yr direction; is the target direction, which is also the unit vector of Xr. for When Yr is the unit vector, for When Zr is the unit vector, C ir0 for The transformation matrix from the reference target attitude to the J2000 inertial system is C xbias Rotation around -Xr axis The corresponding coordinate transformation matrix is, and Consider respectively The three-axis direction vector of the target attitude, C ir0 The transpose of C ir is the attitude conversion matrix from the reference attitude to the J2000 inertial system;

[0024] When the target leaves the singularity interval after passing the top, the roll angle input is limited, and the actual posture is: while keeping pointing to the target, the roll gradually changes from the initial roll angle to the changed theoretical roll angle.

[0025] Furthermore, the angular velocity of the rolling axis varies with the maneuvering mode and capability mode of the satellite, and the angular velocity during wheel control is 0.2° / s to 0.3° / s, and the angular velocity during jet control is 0.3° / s to 0.35° / s.

[0026] Further, in the second case, the Xr axis of the target posture OXrYrZr points to the observed target, and Yr is perpendicular to the normal direction of the sailboard; the plane formed by Xr and the sun vector is the target-sun plane, and the plane normal vector is Yr; Zr is determined by the right-hand rule; the angle between Zr and the sunlight direction vector is not greater than 90°;

[0027] If you need to preserve energy while taking into account data transmission or mobility, choose the angle Rotate Yr and Zr around Xr

[0028] When the angle between the sun vector and the target pointing vector is greater than the protection angle AngPro and less than 180-AngPro, the target pointing coordinate system is defined without singular points, and the target pointing attitude is

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[0030]

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[0038] in, is the representation of Xr in the inertial system, is the representation of the geocentric vector in the inertial system, It is the angle between Zr and the target-geocentric plane; Zr is positive when the projection vector of the plane is biased towards -Yr direction; is the target direction, which is also the unit vector of Xr. for When Yr is the unit vector, for When Zr is the unit vector, C ir0 for The transformation matrix from the reference target attitude to the J2000 inertial system is C xbias Rotation around -Xr axis The corresponding coordinate transformation matrix is, and Consider respectively The three-axis direction vector of the target attitude, C ir0 The transpose of C ir is the attitude conversion matrix from the reference attitude to the J2000 inertial system;

[0039] If the angle between the geocentric vector and Zr in the target pointing coordinate system is greater than 90°, the target pointing coordinate system is rotated 180° around Xr:

[0040]

[0041] like Then C ir =C ir *C x (π)

[0042] Among them, Coi is the transformation matrix of the orbital system relative to the inertial system, C x (π) is the state transfer matrix of a 180° rotation around the x-axis;

[0043] When the target leaves the singularity interval after passing the top, the roll angle input is limited, and the actual posture is: while keeping pointing to the target, the roll gradually changes from the initial roll angle to the changed theoretical roll angle.

[0044] Furthermore, the angular velocity of the rolling axis varies with the maneuvering mode and capability mode of the satellite, and the angular velocity during wheel control is 0.2° / s to 0.3° / s, and the angular velocity during jet control is 0.3° / s to 0.35° / s.

[0045] Furthermore, in the third case, according to the target orbit prediction, the vectors of the local satellite pointing to the target at the two moments before and after are selected, and the normal vector of the plane formed by these two vectors is recorded as Yrbi; the plane formed by Yrbi and Xr is recorded as the target-inertial plane, and the vector in the plane that is perpendicular to Xr and has an angle of no more than 90 with Yrbi is defined as Yr; the Zr axis is determined by the right-hand rule;

[0046] If you need to balance energy or data transmission while maintaining mobility, choose Rotate Yr and Zr around -Xr

[0047] When the satellite relative trajectories are in the same plane, the satellite nominal attitude keeps Xr pointing to the target while making the tracking process basically maneuver around the Yb axis;

[0048] The target pointing attitude is the transformation matrix C of the inertial system relative to the target pointing coordinate system ir ; When Y rbi When the angle between the target pointing vector and the target pointing vector is less than the protection angle AngPro or greater than 180-AngPro, the target pointing coordinate system is defined with a singular point; at this time, the satellite will maintain the target pointing attitude in actual on-orbit control, and the roll angle is controlled by angular velocity damping;

[0049] When Y rbi When the angle between the target pointing vector and the target pointing vector is greater than the protection angle AngPro and less than 180-AngPro, the nominal attitude is:

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[0060] in: is the representation of Xr in the inertial system, Y rbi The inertial space unit vector set for the remote control; To maintain the angle between Yr and the target-inertial plane, Yr is positive when the projection vector of the plane is biased toward Zr; Zr is positive when the projection vector of the plane is biased toward -Yr; is the target direction, which is also the unit vector of Xr. for When Yr is the unit vector, for When Zr is the unit vector, C ir0 for The transformation matrix from the reference target attitude to the J2000 inertial system is C xbias Rotation around -Xr axis The corresponding coordinate transformation matrix is, and Consider respectively The three-axis direction vector of the target attitude, C ir0 The transpose of C ir is the attitude transformation matrix from the reference attitude to the J2000 inertial system.

[0061] Furthermore, in the fourth situation, after the satellite realizes tracking of the target according to the mission requirements, when imaging the target, the roll angle is additionally set to adopt gyro integral control, and the satellite does not rotate around Xr.

[0062] Furthermore, the conversion matrix C ir At the calculated singular point, set the positions of other axes of the target posture as needed.

[0063] A computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the steps of a normal vector-based tracking and aiming attitude maneuvering path planning method are implemented.

[0064] A normal vector-based tracking and aiming attitude maneuvering path planning device comprises a memory, a processor and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the steps of the normal vector-based tracking and aiming attitude maneuvering path planning method are implemented.

[0065] The advantages of the present invention compared with the prior art are:

[0066] (1) The present invention realizes tracking and aiming while maintaining the target attitude setting when the antenna transmits data to the ground as much as possible by applying the normal vector of the plane formed by the target pointing and the ground pointing;

[0067] (2) The present invention realizes tracking and aiming while maintaining the target attitude setting of the sailboard normal to the sun as much as possible by using the target pointing and the sun direction vector to form the normal vector of the plane;

[0068] (3) The present invention achieves the setting of the attitude trajectory for stably tracking the target under limited maneuverability by setting the normal vector relative to the orbital plane. BRIEF DESCRIPTION OF THE DRAWINGS

[0069] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present invention. Moreover, the same reference symbols are used throughout the accompanying drawings to represent the same components. In the accompanying drawings:

[0070] Figure 1 This is a schematic diagram of the target pointing coordinate system of the present invention with phiIN=0 (data transmission guaranteed) (in the figure is a negative angle);

[0071] Figure 2 This is a schematic diagram of the target pointing coordinate system of the present invention when phiIN=1 (energy conservation) (in the figure is a negative angle);

[0072] Figure 3 This is a schematic diagram of the target pointing coordinate system of the present invention with phiIN=2 (maintaining maneuverability) (in the figure is a negative angle);

[0073] Figure 4 This is a schematic diagram of the angle between the camera and the earth according to the first embodiment of the present invention;

[0074] Figure 5This is a schematic diagram of target pointing accuracy and stability according to an embodiment of the present invention;

[0075] Figure 6 This is a schematic diagram of the angle between the normal direction of a solar sail panel and the sun in accordance with the first embodiment of the present invention;

[0076] Figure 7 A schematic diagram of the accuracy of a camera tracking a target according to an embodiment of the present invention;

[0077] Figure 8 A schematic diagram of the stability of a camera tracking a target according to an embodiment of the present invention;

[0078] Fig. 9 This is a schematic diagram of target pointing accuracy in Embodiment 1 of the present invention;

[0079] Fig.10 This is a schematic diagram of target stability according to an embodiment of the present invention;

[0080] Fig.11 This is a relative trajectory change diagram of the second embodiment of the present invention;

[0081] Fig.12 This is a schematic diagram of target pointing accuracy and stability according to the second embodiment of the present invention. DETAILED DESCRIPTION

[0082] In order to better understand the above technical scheme, the technical scheme of the present invention is described in detail below through the accompanying drawings and specific embodiments. It should be understood that the embodiments of the present invention and the specific features in the embodiments are detailed descriptions of the technical scheme of the present invention, rather than limitations on the technical scheme of the present invention. In the absence of conflict, the embodiments of the present invention and the technical features in the embodiments can be combined with each other.

[0083] The following is a further detailed description of a normal vector-based tracking and aiming attitude maneuvering path planning method provided by an embodiment of the present invention in conjunction with the accompanying drawings of the specification. The specific implementation method may include: at any time during the tracking and aiming maneuvering process, the camera optical axis is set to align with the target, and the body axis perpendicular to the camera optical axis is set according to the maneuvering capability and pointing requirements, and the main reference basis for the setting is the selected normal vector direction. The present invention will provide normal vector selection and target attitude setting in four situations: data transmission preservation, energy preservation, maneuverability preservation, and imaging preservation: data transmission preservation means that the angle between the antenna pointing and the direction of the earth is as small as possible, energy preservation means that the angle between the normal of the sailboard and the direction of the sun is as small as possible, maneuverability preservation means that the maneuverability is used as much as possible in the direction of tracking the target; imaging preservation means not rotating around the camera optical axis, and only setting the Euler angles of the other two axes.

[0084] Case 1: Data transmission condition, such as Figure 1, the target attitude is designed by using the normal vector of the plane where the target is pointing and the earth is pointing. Its characteristics are as follows: without loss of generality, the Xr axis of the target attitude OXrYrZr is assumed to point to the observed target; the plane formed by Xr and the geocentric vector is denoted as the target-geocentric plane, then Yr is the target-geocentric plane normal vector. Zr is determined by the right-hand rule. The direction of Yr must ensure that the angle between Zr and the geocentric vector is not greater than 90°. At this time, the nominal attitude of the satellite is conducive to the control of the digital transmission antenna pointing to the ground while keeping Xr pointing to the target.

[0085] If you need to balance energy or mobility while maintaining data transmission, you can choose a suitable angle Rotate Yr and Zr around -Xr

[0086] When the angle between the center of the earth vector and the target pointing vector Xr is less than the protection angle AngPro (the default is 5°) or greater than 180-AngPro, the target pointing coordinate system definition has a singular point. At this time, the satellite will maintain the target pointing attitude during actual on-orbit control.

[0087] In short, when the angle between the center vector and Xr is greater than the protection angle AngPro (the default is 5°) and less than 180-AngPro, the target pointing attitude (the transformation matrix C of the inertial system relative to the target pointing coordinate system) ir ) is calculated as follows:

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[0097] in: is the representation of Xr in the inertial system, is the representation of the geocentric vector in the inertial system. It is the angle between Zr and the target-geocentric plane (Zr is positive when the projection vector of the plane is biased towards -Yr direction).

[0098] When the target passes over the top (i.e. Xr is parallel to the geocentric vector) and leaves the singularity interval, the roll angle will change rapidly. In order to ensure stable pointing, the satellite limits the roll angle input. The actual attitude is: while keeping pointing to the target, the roll gradually changes from the initial roll angle to the changed theoretical roll angle. The roll angular velocity during wheel control is slightly smaller than that during jet control, such as about 0.2° / s~0.3° / s during wheel control and about 0.3° / s~0.35° / s during jet control.

[0099] Case 2: Energy-saving condition, such as Figure 2 , using the normal vector of the plane where the target and the sun are pointing, involving the target attitude. Its characteristics are as follows: Without loss of generality, assume that the Xr axis of the target attitude OXrYrZr points to the observed target; the plane formed by Xr and the sun vector is the target-sun plane, and the plane normal vector is Yr. Zr is determined by the right-hand rule, and the angle between Zr and the sunlight direction vector is not greater than 90°. At this time, the nominal attitude of the satellite is conducive to the ground control of the digital transmission antenna while keeping Xr pointing to the target.

[0100] If you need to maintain energy while taking into account data transmission or mobility, you can choose a suitable angle Rotate Yr and Zr around Xr

[0101] When the angle between the sun vector and the target pointing vector is less than the protection angle AngPro (the default is 5°) or greater than 180-AngPro, the target pointing coordinate system definition has a singular point. At this time, the satellite will maintain the target pointing attitude during actual on-orbit control.

[0102] Target pointing attitude calculation method:

[0103] When the angle between the sun vector and the target pointing vector is greater than the protection angle AngPro (the default is 5°) and less than 180-AngPro, the target pointing attitude (the conversion matrix C of the inertial attitude relative to the target attitude) ir ) is calculated as follows:

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[0113] If the angle between the geocentric vector and Zr in the target pointing coordinate system is greater than 90°, the target pointing coordinate system is rotated 180° around Xr:

[0114]

[0115] like Then C ir =C ir *C x (π)

[0116] in: is the representation of Xr in the inertial system, is the unit vector of the local star pointing to the sun in the inertial system. oi is the transformation matrix of the orbital system relative to the inertial system, C oi (π) is the transformation matrix for rotating π radians around the x-axis.

[0117] When phiIN=1 is set, the roll angle will change rapidly when the target leaves the singularity interval after passing the top (i.e., Xr is parallel to the geocentric vector). At this time, in order to ensure stable pointing, the satellite limits the roll angle input. The actual attitude is: while keeping pointing to the target, the roll gradually changes from the initial roll angle to the changed theoretical roll angle. The roll angular velocity during wheel control is slightly smaller than that during jet control.

[0118] Case 3: Keep the maneuvering condition, such as Figure 3 , the target attitude is set by setting the axis of minimum inertia in the direction of the normal vector of the target relative trajectory. Its characteristics are as follows: according to the target orbit prediction, the vector of the satellite pointing to the target at the two moments before and after (usually before and after the moment of the target's closest distance) is selected, and the normal vector of the plane formed by these two vectors is recorded as Y rbi To overcome the situation where the relative trajectory is not completely in one plane, Y rbi The plane formed by Xr is the target-inertial plane. rbi The vector with an angle of no more than 90° is defined as Yr. The Zr axis is determined by the right-hand rule.

[0119] If you need to take into account energy or data transmission while maintaining mobility, you can choose the appropriate Rotate Yr and Zr around -Xr

[0120] When the relative trajectories of the satellites are basically in the same plane, the nominal attitude of the satellite can basically maneuver around the Yb axis during the tracking process while keeping Xr pointing to the target.

[0121] The target pointing attitude is the transformation matrix Cir of the inertial system relative to the target pointing coordinate system. rbi When the angle between the target pointing vector and the target pointing vector is less than the protection angle AngPro (the default is 5°) or greater than 180-AngPro, the target pointing coordinate system defined in Section 3.5.3 has a singular point. At this time, the satellite will maintain the target pointing attitude in the actual on-orbit control, and the roll angle is controlled by angular velocity damping.

[0122] When Y rbi When the angle between the target pointing vector and the target pointing vector is greater than the protection angle AngPro (the default is 5°) and less than 180-AngPro, the nominal attitude (the transformation matrix C of the inertial attitude relative to the target pointing reference coordinate system) irs ) is calculated as follows:

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[0133] in: is the representation of Xr in the inertial system, and Yrbi is the inertial space unit vector set by the remote control. To maintain the angle between Yr and the target-inertial plane (Yr is positive when the projection vector of the plane is biased towards Zr).

[0134] Case 4: Image-preserving condition. Normal vector is not used and the direction of the camera optical axis is set only by gyro integral.

[0135] Its features are as follows:

[0136] When the satellite tracks the target according to the aforementioned phiIN=0 / 1 / 2 based on the mission requirements, when using the detailed inspection camera to image the target, the rolling angle can be additionally set to use gyro integral control, that is, the remote control sets phiIN=3 (to maintain imaging). In this way, the satellite does not rotate around Xr, so as to improve the stability of the satellite around the Xr axis and ensure the imaging quality.

[0137] If the satellite keeps phiIN=3 for a long time, it will affect the pointing direction of Yr and Zr in inertial space, so it is recommended to use it in the short term.

[0138] Embodiment 1

[0139] Table 1 Example 1

[0140] Position of this star Target 1 track Epoch time October 1, 2020 8 October 1, 2020 8 Semi-major axis a 42 hours 116 minutes 3317 seconds km 42 hours 166 minutes 3317 seconds km Eccentricity 0.0002 0.0002 Orbital inclination 0.001° 0.001° ascending node i point red 287.929° 287.929° Near longitude point 0° 0° Straight angle anomaly 345° 345.03°

[0141] When observing target 1, the antenna is on the +Z axis, the control effect of the data transmission is as follows: Figure 4 , 5 shown.

[0142] Observe target 1, set the vertical direction of the sailboard as +Z direction, and the control effect when maintaining energy is as follows Figure 6 , 7 , as shown in Figure 8.

[0143] The control result when maintaining the direction is as follows Fig. 9 , 10 shown.

[0144] Embodiment 2

[0145] Table 2 Example 2

[0146] Position of this star Target 2 Track Epoch time October 1, 2020 8 October 1, 2020 8 Semi-major axis a 42 hours 086 minutes 3317 seconds km 4 hours 2116 minutes 331 seconds 7 km Eccentricity 0.0006 0.0002 Orbital inclination 0.286° 7.001° ascending node i point red 287.929° 287.929° Near longitude point 0° 0° Straight angle anomaly 340° 340°

[0147] Calculation of relative path normal vector:

[0148] To increase the clarity of the captured image, the position with the smallest relative distance is usually selected for tracking. The present invention discusses an example where the angular velocity of the line of sight is large when the relative distance is small, such as Fig.11 As shown. In the figure, x, y, and z are the three axes of the target star's orbital system, that is: the orbital center is at the target star, the x-axis points from the center of the earth to the target star, the y-axis points to the negative direction of the angular momentum of the target star's orbital plane, and the z-axis satisfies the right-hand rule. It can be seen from the figure that: (1) The projection of the plane where the relative trajectory is located on the xoy plane is a straight line, so the degree to which the coplanar assumption is satisfied actually depends on the degree of change in the xy plane of the orbital system; (2) At the position where the relative distance is minimum, the projection of the relative vector on the xy axis of the orbital system changes its sign, the rate of change of the z-axis projection changes its sign, and the line of sight angular velocity is large. In the following, tmin is used to represent the moment when the relative distance is minimum.

[0149] To estimate the normal vector of the plane where the relative trajectory is located, the present invention sets the time interval Δt and uses r(t) to represent the relative position vector at time t. Then the normal vector is:

[0150] Y rbi =r(tmin+Δt)×r(tmin-Δt)

[0151] In fact, we can also use the vectors r at the three moments tmin-Δt, tmin, and tmin+Δt to calculate the normal vectors two by two, and take their average as the normal vector Y ri .

[0152] Considering that the orbital system will change slowly, r(t) and Y ri The position vector of the inertial system is used. In the following calculation, the inertial system vector Y is required ri In the observational system, the expression Y rbi =C rbi Y ri . Control effect such as Fig.12 shown.

[0153] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

[0154] The contents not described in detail in the specification of the present invention belong to the common knowledge of those skilled in the art.

Claims

1. A normal vector-based tracking and aiming attitude maneuvering path planning method, characterized in that: At any time during the tracking and aiming maneuver, the camera optical axis is set to align with the target, and the direction of the satellite body axis perpendicular to the camera optical axis is set according to the maneuverability and pointing requirements, and the setting basis is that the body axis is in the set normal vector direction; The setting of the normal vector direction is determined according to the tracking task, and includes: Case 1: When the maneuverability meets the mission requirements and the antenna should always communicate with the ground, the communication mode is entered. At this time, the body axis with the largest angle between the camera optical axis and the antenna is found, and its direction is set as the normal vector of the plane where the tracking direction and the ground direction are located; Case 2: When the maneuverability meets the mission requirements and the sailboard should generate electricity all the time, the energy conservation mode is entered. At this time, the main body axis with the largest angle with the camera optical axis and the sailboard axis is selected, and its direction is set as the normal vector of the plane where the tracking direction and the sun direction are located; Case 3: When the maneuverability can only meet the tracking and aiming requirements, the satellite enters the maneuvering mode. At this time, the body axis with the largest angle with the orbital plane is selected, and its direction is set as the normal vector of the plane where the satellite relative trajectory is located. Case 4: When the tracking and aiming stability is required to be the highest, enter the image preservation mode. At this time, only the camera optical axis is set to point to the target, and other axes are not controlled.

2. The method for maneuvering path planning based on normal vector tracking and aiming posture according to claim 1 is characterized in that: In the first case, the Xr axis of the target attitude OXrYrZr points to the observed target, and Zr is the antenna direction; the plane formed by Xr and the geocentric vector is the target-geocentric plane, and Yr is the target-geocentric plane normal vector; Zr is determined by the right-hand rule, and the direction of Yr ensures that the angle between Zr and the geocentric vector is not greater than 90°; the nominal attitude of the satellite at this time is conducive to data transmission between the digital antenna and the ground while keeping Xr pointing to the target; If you need to ensure data transmission between the antenna and the ground while taking into account energy or mobility, choose an angle Rotate Yr and Zr around -Xr When the angle between the centroid vector and Xr is greater than the protection angle AngPro and less than 180-AngPro, the target pointing coordinate system is defined without singular points, and the target pointing attitude is in, is the representation of Xr in the inertial system, is the representation of the geocentric vector in the inertial system, It is the angle between Zr and the target-geocentric plane; Zr is positive when the projection vector of the plane is biased towards -Yr direction; is the target direction, which is also the unit vector of Xr. for When Yr is the unit vector, for When Zr is the unit vector, C ir0 for The transformation matrix from the reference target attitude to the J2000 inertial system is C xbias Rotation around -Xr axis The corresponding coordinate transformation matrix is, and Consider respectively The three-axis direction vector of the target attitude, C ir0 The transpose of C ir is the attitude conversion matrix from the reference attitude to the J2000 inertial system; When the target leaves the singularity interval after passing the top, the roll angle input is limited, and the actual posture is: while keeping pointing to the target, the roll gradually changes from the initial roll angle to the changed theoretical roll angle.

3. The method for maneuvering path planning based on normal vector tracking and aiming posture according to claim 2 is characterized in that: The angular velocity of the rolling axis varies with the maneuvering mode and capability mode of the satellite. The angular velocity during wheel control is 0.2° / s to 0.3° / s, and the angular velocity during jet control is 0.3° / s to 0.35° / s.

4. The method for maneuvering path planning based on normal vector tracking and aiming posture according to claim 1, characterized in that: In the second case, the Xr axis of the target posture OXrYrZr points to the observed target, and Yr is perpendicular to the normal direction of the sailboard; the plane formed by Xr and the sun vector is the target-sun plane, and the plane normal vector is Yr; Zr is determined by the right-hand rule; the angle between Zr and the sunlight direction vector is not greater than 90°; If you need to preserve energy while taking into account data transmission or mobility, choose the angle Rotate Yr and Zr around Xr When the angle between the sun vector and the target pointing vector is greater than the protection angle AngPro and less than 180-AngPro, the target pointing coordinate system is defined without singular points, and the target pointing attitude is in, is the representation of Xr in the inertial system, is the representation of the geocentric vector in the inertial system, It is the angle between Zr and the target-geocentric plane; Zr is positive when the projection vector of the plane is biased towards -Yr direction; is the target direction, which is also the unit vector of Xr. for When Yr is the unit vector, for When Zr is the unit vector, C ir0 for The transformation matrix from the reference target attitude to the J2000 inertial system is C xbias Rotation around -Xr axis The corresponding coordinate transformation matrix is, and Consider respectively The three-axis direction vector of the target attitude, C ir0 The transpose of C ir is the attitude conversion matrix from the reference attitude to the J2000 inertial system; If the angle between the geocentric vector and Zr in the target pointing coordinate system is greater than 90°, the target pointing coordinate system is rotated 180° around Xr: like Then C ir =C ir *C x (π) Among them, Coi is the transformation matrix of the orbital system relative to the inertial system, C x (π) is the state transfer matrix of a 180° rotation around the x-axis; When the target leaves the singularity interval after passing the top, the roll angle input is limited, and the actual posture is: while keeping pointing to the target, the roll gradually changes from the initial roll angle to the changed theoretical roll angle.

5. The method for maneuvering path planning based on normal vector tracking and aiming posture according to claim 4 is characterized in that: The angular velocity of the rolling axis varies with the maneuvering mode and capability mode of the satellite. The angular velocity during wheel control is 0.2° / s to 0.3° / s, and the angular velocity during jet control is 0.3° / s to 0.35° / s.

6. The method for maneuvering path planning based on normal vector tracking and aiming posture according to claim 1 is characterized in that: In the third case, according to the target orbit prediction, the vectors of the satellite pointing to the target at the previous and next moments are selected, and the normal vector of the plane formed by these two vectors is recorded as Yrbi; the plane formed by Yrbi and Xr is recorded as the target-inertial plane, and the vector in the plane that is perpendicular to Xr and has an angle of no more than 90 with Yrbi is defined as Yr; the Zr axis is determined by the right-hand rule; If you need to balance energy or data transmission while maintaining mobility, choose Rotate Yr and Zr around -Xr When the satellite relative trajectories are in the same plane, the satellite nominal attitude keeps Xr pointing to the target while making the tracking process basically maneuver around the Yb axis; The target pointing attitude is the transformation matrix C of the inertial system relative to the target pointing coordinate system ir ; When Y rbi When the angle between the target pointing vector and the target pointing vector is less than the protection angle AngPro or greater than 180-AngPro, the target pointing coordinate system is defined with a singular point; at this time, the satellite will maintain the target pointing attitude in actual on-orbit control, and the roll angle is controlled by angular velocity damping; When Y rbi When the angle between the target pointing vector and the target pointing vector is greater than the protection angle AngPro and less than 180-AngPro, the nominal attitude is: in: is the representation of Xr in the inertial system, Y rbi The inertial space unit vector set for the remote control; To maintain the angle between Yr and the target-inertial plane, Yr is positive when the projection vector of the plane is biased toward Zr; Zr is positive when the projection vector of the plane is biased toward -Yr; is the target direction, which is also the unit vector of Xr. for When Yr is the unit vector, for When Zr is the unit vector, C ir0 for The transformation matrix from the reference target attitude to the J2000 inertial system is C xbias Rotation around -Xr axis The corresponding coordinate transformation matrix is, and Consider respectively The three-axis direction vector of the target attitude, C ir0 The transpose of C ir is the attitude transformation matrix from the reference attitude to the J2000 inertial system.

7. A normal vector-based tracking and aiming posture maneuvering path planning method according to any one of claims 2 to 6, characterized in that: In the fourth situation, after the satellite realizes tracking of the target according to the mission requirements, when imaging the target, the roll angle is additionally set to adopt gyro integral control, and the satellite does not rotate around Xr.

8. The method for maneuvering path planning based on normal vector tracking and aiming posture according to claim 1, characterized in that: The transformation matrix C ir At the calculated singular point, set the positions of other axes of the target posture as needed.

9. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 6 are implemented.

10. A normal vector-based tracking and aiming attitude maneuvering path planning device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the computer program, the steps of the method according to any one of claims 1 to 6 are implemented.

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