CN-119879947-B - Spatial target vision measurement method combined with acceleration drift estimation

Abstract

The invention relates to the technical field of space on-orbit short-distance relative visual navigation, in particular to a space target visual measurement method combining acceleration drift estimation, which is used for tracking an acceleration sensor and a camera arranged on a spacecraft, wherein S1 is used for acquiring initial relative position information and relative speed information through a measurement system, S2 is used for acquiring an acceleration value and a space target image in real time, S3 is used for establishing a relative motion equation, substituting the acquired acceleration value and the relative position and relative speed information at the previous moment into the relative motion equation to calculate position information, S4 is used for calculating error amount, and estimating the relative position information, the relative speed information and the error of the acceleration value in the dynamics equation through a filtering algorithm according to the error amount to correct the calculation result obtained in the dynamics equation, so that the accurate positioning of the target spacecraft can be realized.

Inventors

• YUAN JIANPING
• YUAN JING
• MA CHUAN
• YANG DONG
• CHENG LEI

Assignees

• 苏州三垣航天科技有限公司

Dates

Publication Date

20260508

Application Date

20250117

Claims (2)

1. 1. A visual measurement method of a space target combined with acceleration drift estimation is characterized in that an acceleration sensor and a camera are arranged on a tracking spacecraft, The method comprises the following steps: S1, acquiring initial relative position information and relative speed information through a measuring system, wherein the relative position information and the relative speed information are the position and speed information of a space target relative to the tracking spacecraft; S2, acquiring an acceleration value and a space target image in real time, wherein the acceleration value is a parameter measured by the acceleration sensor; S3, establishing a relative motion equation, substituting the acceleration value at the current moment and the relative position and relative speed information of a calculation period before the current moment into the relative motion equation, and calculating position information, wherein the position information is the relative position of a space target at the current moment relative to the tracking spacecraft; S4, calculating an error amount, and estimating errors of relative position information, relative speed information and acceleration values in a dynamic equation through a filtering algorithm according to the error amount to correct a calculation result obtained in the dynamic equation, wherein the error amount is an error between the position information and image position information, and the image position information is a position of a space target obtained according to a space target image; In step S4, after converting the position information into image coordinate system position information, calculating an error between the image coordinate system position information and the image position information, wherein the image coordinate system position information corresponds to a coordinate system of space target image information; Converting the position information into image coordinate system position information according to the following formula: Wherein, the The spatial target position Pc under the camera coordinate system is obtained by converting the position information, f is the focal length of the camera, and (Cx, cy) is the coordinate of the main point of the camera on the image pickup plane; the spatial target position information P H in the track coordinate system is converted into a spatial target position Pc in the camera coordinate system by: assuming that the optical axis of the camera is parallel to the Y direction of the track coordinate system, and the x axis and the Y axis of the camera plane are consistent with the direction of the track coordinate system X, Z, the posture transformation matrix from the camera coordinate system to the track coordinate system is as follows The position information P H is converted into a spatial target position Pc in the camera coordinate system by: Wherein, the The camera coordinate system is aligned with the tracking spacecraft body coordinate system according to the gesture matrix of the tracking spacecraft body coordinate system relative to the orbit coordinate system measured by the gesture measurement system; The error MSE between the position information and the image position information is obtained by: Wherein, (u, v) is the image position information, Position information for the image coordinate system; if a plurality of target detection results are output, only the target detection result closest to the predicted position is reserved, and the central position of the space target is calculated as the image position information according to the target detection result.
2. 2. The method for vision measurement of a space object in combination with acceleration drift estimation according to claim 1, wherein in step S3, a relative motion coordinate system for tracking a spacecraft and the space object is defined by a spacecraft orbit coordinate system, and a relative motion equation established under the relative motion coordinate system is as follows: Wherein n is the orbit angular velocity of the target spacecraft, and f= [ f x ,f y ,f z ] is the acceleration value; The results obtained according to the relative motion equation are as follows: Wherein T is a calculation period, [ x k ,y k ,z k ] is the position information of the current time k, [ delta x k-1 ,Δy k-1 ,Δz k-1 ] is the relative position error estimated by a filtering algorithm, For the relative velocity of the spatial target at the current instant k, For the relative velocity error estimated by the filtering algorithm, Δf= [ Δf x ,Δf y ,Δf z ] is the acceleration error estimated by the filtering algorithm, and k-1 represents the time of the previous calculation cycle of the current time k.

Description

Spatial target vision measurement method combined with acceleration drift estimation Technical Field The invention relates to the technical field of space flight on-orbit short-distance relative visual navigation, in particular to a space target visual measurement method combining acceleration drift estimation. Background Almost all on-orbit operation tasks involve guiding the approach to the target spacecraft by visual sensors, performing the operation tasks in the appropriate locations. Because the common CCD camera has a limited measuring range, a target is difficult to 'see' at a distance of hundreds of meters, and in the distance range, the ground tracking measurement system is limited by tracking conditions, so that the relative position of the target relative to the tracking spacecraft cannot be accurately measured. In order to solve the problem of relative measurement of the transition section between ground measurement and vision measurement, the current solution is to use a relatively expensive microwave radar or a long-focal-length camera for measurement. The target recognition technology based on deep learning is increasingly widely applied to ground scenes, and weak and small targets in remote sensing images can be recognized at present. This technique is applied to spatial target recognition. The network is trained through ground simulation data and pseudo real pictures, and the training network is loaded to the on-board calculation unit, so that target spacecrafts with different scales can be rapidly and accurately identified. However, when the distance between the target and the camera is large, the projection of the target on the imaging plane occupies few pixels, and it is difficult to separate the target spacecraft from the resident target of the space background, and the traditional track association method is not applicable any more because the tracking spacecraft is in a maneuvering state. At this time, a part of prior information is needed to screen suspected targets. Disclosure of Invention In order to overcome the defects in the prior art, the invention provides a space target vision measurement method combined with acceleration drift estimation, which realizes accurate positioning of a target spacecraft. In order to achieve the above object, the present invention is realized by the following technical scheme: a visual measurement method for the space target combined with acceleration drift estimation features that an acceleration sensor and a camera are installed to tracking spacecraft, The method comprises the following steps: S1, acquiring initial relative position information and relative speed information through a measuring system, wherein the relative position information and the relative speed information are the position and speed information of a space target relative to the tracking spacecraft; S2, acquiring an acceleration value and a space target image in real time, wherein the acceleration value is a parameter measured by the acceleration sensor; S3, establishing a relative motion equation, substituting the acceleration value at the current moment and the relative position and relative speed information of a calculation period before the current moment into the relative motion equation, and calculating position information, wherein the position information is the relative position of a space target at the current moment relative to the tracking spacecraft; And S4, calculating an error amount, and estimating errors of relative position information, relative speed information and acceleration values in the dynamic equation through a filtering algorithm according to the error amount to correct a calculation result obtained in the dynamic equation, wherein the error amount is an error between the position information and image position information, and the image position information is a position of a space target obtained according to a space target image. In a further step S3, a relative motion coordinate system of the tracking spacecraft and the space target is defined by a spacecraft orbit coordinate system, and a relative motion equation established under the relative motion coordinate system is as follows: Wherein n is the orbit angular velocity of the target spacecraft, and f= [ f x,fy,fz ] is the acceleration value; The results obtained according to the relative motion equation are as follows: Wherein T is a calculation period, [ x k,yk,zk ] is the position information of the current time k, [ delta x k-1,Δyk-1,Δzk-1 ] is the relative position error estimated by a filtering algorithm, For the relative speed of the current time-of-day space object,For the relative velocity error estimated by the filtering algorithm, Δf= [ Δf x,Δfy,Δfz ] is the accelerometer error estimated by the filtering algorithm, and k-1 represents the time of the previous calculation cycle of the current time k. In addition, in the spatial target vision measurement method combined with accelera