A method for adjusting the posture of a TDICCD optical satellite during imaging

Abstract

The application discloses a TDICCD optical satellite moving imaging posture adjusting method, establishes moving imaging with the angle of the subsatellite point track and push scanning, and comprises the following steps: S100, a transfer matrix from an inertial coordinate system to an orbit coordinate system is calculated; S200, a transfer matrix from the orbit coordinate system to a satellite body coordinate system is calculated; S300, a moving speed of an imaging target point D relative to an image surface is calculated; S400, an integral time is obtained based on the calculation of S300; S500, whether the TDICCD camera satisfies imaging is judged based on the integral time, and the posture maneuvering angular velocity is re-planned if the TDICCD camera does not satisfy imaging; S600, a drift angle is calculated based on the relative speed; and S700, the drift angle is corrected, so that the moving imaging of the TDICCD optical satellite is realized. The integral time of the TDICCD in the moving imaging is calculated, the posture maneuvering angular velocity in the moving imaging is planned, the TDICCD camera imaging is satisfied, and the moving imaging is suitable. The drift angle correction method introduces the active push scanning angular velocity of the satellite on the drift angle calculation model, and is suitable for the moving imaging.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of satellite attitude adjustment, in particular to a TDICCD optical satellite dynamic imaging attitude adjustment method. BACKGROUND

[0002] The traditional earth observation satellite is in a stable state when imaging, that is, the roll and pitch attitude angular velocities are close to zero, and the satellite relies on the orbital speed to achieve passive push-broom imaging of the ground target, and the push-broom direction is parallel to the satellite flight direction. In order to improve the imaging efficiency of the satellite or to achieve a strip push-broom that is not parallel to the satellite flight direction, the satellite gradually develops a dynamic imaging mode. In the dynamic imaging process, the satellite has an active push-broom angular velocity, at this time the roll and pitch attitude angular velocities of the satellite are no longer zero and will change with time. The traditional TDICCD optical satellite needs to correct the drift angle when imaging to ensure that the push-broom direction of the camera on the satellite is consistent with the speed direction of the image motion, thereby achieving push-broom imaging. For the TDICCD optical satellite dynamic imaging satellite, due to the introduction of the roll and pitch angular velocities, the TDICCD integration time will be affected, and the attitude adjustment method needs to limit the adjustment of the attitude angular velocity from the load angle. On the other hand, in order to ensure that the push-broom direction of the camera is consistent with the speed direction of the image motion, active control of the drift angle is also needed. However, since the satellite has an active rotation angular velocity in the roll and pitch directions, the satellite attitude control method during dynamic imaging is quite different from that during stable state. The traditional satellite drift angle calculation only involves passive push-broom imaging during stable attitude, and the influence of the roll and pitch angular velocities is not considered, so it cannot meet the requirements of dynamic imaging.

[0003] The existing attitude correction method has the following disadvantages:

[0004] 1. No attitude adjustment method for dynamic imaging

[0005] The current attitude adjustment method of the imaging satellite cannot realize the dynamic imaging mode with an active push-broom angular velocity, and can only realize the passive push-broom imaging mode of the satellite along the orbit. The existing attitude adjustment method cannot meet the curve strip imaging mode of the satellite for complex tasks such as ground tracking.

[0006] 2. The drift angle correction method does not introduce an active push-broom angular velocity

[0007] The current drift angle correction method does not introduce the roll and pitch attitude angular velocities of the satellite in the processing of the drift angle calculation model, that is, the roll and pitch attitude angular velocities are set to zero, which cannot meet the dynamic imaging mode with non-zero roll and pitch attitude angular velocities of the satellite.

[0008] 3. A method for adjusting the imaging attitude angle of a TDICCD optical satellite in motion without constraints from the optical load of the TDICCD.

[0009] Therefore, it is necessary to design a method for adjusting the imaging attitude angle of a TDICCD optical satellite in motion SUMMARY

[0010] The present application aims to provide a method for adjusting the imaging attitude angle of a TDICCD optical satellite in motion to solve the problems in the background art.

[0011] To solve the above technical problems, the present application provides the following technical solutions.

[0012] A method for adjusting the imaging attitude angle of a TDICCD optical satellite in motion, which establishes a TDICCD optical satellite in motion with a push-broom at an angle of η with respect to the subsatellite point trajectory, comprises the following steps:

[0013] S100, a transfer matrix R from an inertial coordinate system O i x i y i z i to an orbital coordinate system O o x o y o z o is calculated: oi

[0014]

[0015] wherein i is the angle between the sun-synchronous orbit of the satellite and the ecliptic plane, f is the true anomaly, ω is the argument of perigee, and Ω is the right ascension of the ascending node;

[0016] S200, a transfer matrix R from the orbital coordinate system O o x o y o z o to a satellite body coordinate system O b x b y b z b is calculated: bo

[0017]

[0018] wherein α is the angle of rotation of the satellite around the O o z o axis by an angle of η, and then the angle of rotation around the satellite body O b y b axis;

[0019] S300, the moving speed of an imaging target point D with respect to the image plane is calculated:

[0020] ​​

[0021] Wherein: ωe is the earth rotation angular velocity, ωo is the orbit angular velocity, ωη is the attitude maneuver angular velocity, R is the earth radius, L is the slant range from the imaging point to the satellite (the small o and b are missing the identification explanation);

[0022] S400, based on the V 相对 The integral time is calculated:

[0023]

[0024] Wherein: d0 is the pixel size of the TDICCD device, f is the focal length of the on-board camera;

[0025] S500, according to the T int , judge whether the TDICCD camera satisfies imaging, if not, re-plan the attitude maneuver angular velocity ω η ;

[0026] S600, according to the The drift angle is calculated as

[0027] S700, correct the drift angle, so as to realize the dynamic imaging of TDICCD optical satellite.

[0028] According to the above technical scheme, the inertial coordinate system O i x i y i z i And the transfer operation of the orbit coordinate system O o x o y o z o Is:

[0029] The satellite rotates around the orbit coordinate system O o z o Axis, that is, the satellite body O b z b Axis rotates η angle, wherein η≥90°, and then rotates around the satellite body O b y b Axis at the attitude maneuver angular velocity ω η And the orbit direction forms η angle to carry out push-broom imaging, at a certain moment, the push-broom angle is equal to the angle α, the push-broom imaging target point is D point, so as to construct the relative coordinate system.

[0030] According to the above technical scheme, each term of the calculation formula in the S300 is specifically:

[0031] A) The item is the absolute motion velocity of the target point D in the inertial coordinate system, which is converted into the camera coordinate system, and has R bo ((R oi [ω e ] i )×[R] o );

[0032] B) The item is the relative velocity of the target point D due to the rotation of the orbit motion coordinate system, which is converted into the camera coordinate system, and has R bo [[ω o ] o ×[R] o ];

[0033] C) The item is the relative velocity of the target point D due to the rotation of the satellite body coordinate system, which is converted into the camera coordinate system, and has [ω η ] b ×[L] b .

[0034] According to the above technical solution, the drift angle correction method of the S700 is:

[0035] Returning to S100, the push-broom imaging is repeated, and then the satellite body O b z b axis is adjusted by the angle ψ, so that the dynamic imaging suitable for the TDICCD optical satellite is realized.

[0036] Compared with the prior art, the present application has the following beneficial effects:

[0037] 1. The present application calculates the integration time of the TDICCD in dynamic imaging, and plans the attitude maneuver angular velocity in dynamic imaging to meet the TDICCD camera imaging, which is suitable for dynamic imaging.

[0038] 2. The drift angle correction method of the present application introduces the active push-broom angular velocity of the satellite on the drift angle calculation model, which is suitable for dynamic imaging. BRIEF DESCRIPTION OF DRAWINGS

[0039] Figure 1 is the example projection schematic diagram of the present application. DETAILED DESCRIPTION

[0040] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the protection scope of the present application.

[0041] The application provides a technical solution: a TDICCD optical satellite moving imaging attitude adjusting method, which establishes moving imaging with a push-broom of η angle with a subsatellite point track, and comprises the following steps:

[0042] S100, an inertial coordinate system O i x i y i z i is calculated to a transfer matrix R o x o y o z o of an orbit coordinate system O oi :

[0043]

[0044] Wherein i is an included angle between a sun-synchronous orbit of the satellite and a solar ecliptic plane, f is a true anomaly, ω is an argument of perigee, and Ω is a right ascension of the ascending node;

[0045] S200, an orbit coordinate system O o x o y o z o is calculated to a transfer matrix R b x b y b z b of a satellite body coordinate system O bo :

[0046]

[0047] Wherein α is a rotation angle of the satellite around O o z o after rotating by η degrees and then rotating around a satellite body O b y b axis;

[0048] S300, a moving speed of an imaging target point D relative to an image plane is calculated:

[0049]

[0050] Wherein ω e is an earth rotation angular velocity, ω o is an orbit angular velocity, ω η is an attitude maneuver angular velocity, R is an earth radius, and L is a slant range from a photographing point to the satellite (the small o and the small b are missing);

[0051] S400, an integral time is calculated based on V 相对 obtained in S300:

[0052]

[0053] Wherein: d0 is the pixel size of the TDICCD device, and f is the focal length of the on-board camera.

[0054] S500, T int obtained from S400 is calculated. η ;

[0055] S600, T obtained from S300 is calculated.

[0056] S700, the deflection angle is corrected, so as to realize the moving imaging of the TDICCD optical satellite.

[0057] Specifically, the inertial coordinate system O i x i y i z i of S100 is transformed into the orbital coordinate system O o x o y o z o , and the transformation operation is as follows:

[0058] The satellite rotates around the orbital coordinate system O o z o axis, i.e. the satellite body O b z b axis, by an angle η, wherein η≥90°, and then rotates around the satellite body O b y b axis at the attitude maneuver angular velocity ω η and the orbital direction by an angle η to perform push-broom imaging, at a certain moment, the push-broom angle is equal to the angle α, the push-broom imaging target point is D point, and thus the relative coordinate system is constructed.

[0059] Specifically, each term of the calculation formula in S300 is as follows:

[0060] A) The term is the absolute motion speed of the target point D in the inertial coordinate system, which is converted into the camera coordinate system, and thus R bo ((R oi [ω e ] i )×[R] o );

[0061] B) The item is the related velocity of the target point D due to the rotation of the orbit motion coordinate system, converted into the camera coordinate system, then has: R bo [[ω o ] o ×[R] o ];

[0062] C) The item is the related velocity of the target point D due to the rotation of the satellite body coordinate system, in the camera coordinate system, then has: [ω η ] b ×[L] b .

[0063] Specifically, the S700's drift angle correction method is:

[0064] Return to S100 to repeat the operation to push the imaging, and then adjust the angle of the satellite body O b z b axis ψ, then the TDICCD optical satellite can be realized.

[0065] It should be noted that in this paper, such as the first and second relationship terms are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between the entities or operations. Moreover, the term "includes", "contains" or any other variant thereof is intended to cover non-exclusive inclusion, so that the process, method, article or equipment including a series of elements not only includes those elements, but also includes other elements not explicitly listed or inherent to such process, method, article or equipment.

[0066] Finally, it should be noted that: the above only for the preferred embodiments of the present application, and not for the purpose of limiting the present application, although the present application is described in detail with reference to the foregoing embodiments, for those skilled in the art, it still can be modified to the technical solutions recorded in the foregoing embodiments, or to replace some of the technical features. Any modification, equivalent replacement, improvement, etc. within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A method for adjusting the attitude of a TDICCD optical satellite during imaging, characterized in that, establishing a moving imaging with the ground track of a sub-satellite point angle push-broom, comprising the following steps: S100, computing the inertial coordinate system to the orbital coordinate system transfer matrix : ； wherein: is the angle between the sun-synchronous orbit in which the satellite is operating and the ecliptic plane of the sun, is the true anomaly, is the argument of perigee, is the right ascension of the ascending node; S200, computing the orbit coordinate system to the satellite body coordinate system transfer matrix : ； wherein: for the satellite to rotate about the satellite body axis by an angle; and rotate about the satellite body S300, calculate the moving speed of the imaging target point D relative to the image plane: ； wherein: is the earth rotation angular velocity, is the orbit angular velocity, is the attitude maneuver angular velocity, is the earth radius, is the slant range from the photograph point to the satellite, and each term of the calculation formula is specifically: A) The item is the absolute motion velocity of the target point D in the inertial coordinate system, which is converted into the camera coordinate system, and then has: ​ B) Item is the induced velocity of the target point D due to the rotation of the orbital motion coordinate system, converted into the camera coordinate system, then ; C) The item is the dependent velocity of the target point D due to the rotation of the satellite body coordinate system. In the camera coordinate system, we have ; S400, based on the obtained in S300 The integration time is calculated ； wherein: is the pixel size of the TDICCD device, is the focal length of the on-board camera; S500、According to S400 obtained , determine whether the TDICCD camera meets the imaging, and if not, re-plan the attitude maneuver angular velocity ; S600、obtaining the , the deflection angle is calculated as ; S700, correct the deflection angle, specifically, return to S100 to repeat the operation of push-broom imaging, and then rotate around the satellite body axis adjustment angle, and then the TDICCD optical satellite can be applied to dynamic imaging.

2. The method according to claim 1, wherein the method is a method for adjusting the attitude of a TDICCD optical satellite in motion. The inertial coordinate system of the S100 The transfer operation with the orbital coordinate system is: Satellite around the orbital coordinate system Axis, i.e. satellite body Axis rotation Angle, after which Again around the satellite body Axis to attitude maneuver angular velocity With the orbital direction Angle push-broom imaging, at a certain moment, the push-broom angle is equal to the angle At this time, the push-broom imaging target point is D point, thereby constructing a relative coordinate system.

Images