Research On Measurement Of Relative Pose For Non-cooperative Space Targets Based On SLAM

In recent years,with the increasing frequency of human space activities and the everincreasing number of on-orbit spacecraft,problems caused by space-failed spacecraft and space debris have attracted widespread attention from countries.They not only occupy a lot of space resources,but also threaten other spacecraft's safety.Unlike other on-orbit spacecraft,they are characterized by the lack of cooperative artificial beacons,and their shapes,sizes,and rotational angular speeds are completely unknown.In this case,whether it is the maintenance of a defective spacecraft or the cleanup of space debris,the key issue that must be solved first is the pose measurement problem of space non-cooperative targets.However,most current non-cooperative target measurement programs still require known prior information,such as non-cooperative target types and partial geometric features,or need to complete the modeling of the target first through sequence image collection.In view of this situation,this paper considers the use of Simultaneous Localization and Mapping(SLAM)method to solve the problem of relative pose measurement of non-cooperative targets.We design a measurement plan and build a ground experiment platform to complete the simulation verification.The main research contents of the paper are as follows:Firstly,the relative measurement coordinate system is built on the basis of the orbital tracking spacecraft.Based on the sensors used,the measurement model is analyzed and deduced.The camera and inertial measurement component calibration algorithm are studied and the calibration experiment of the hardware is completed.Based on this,the existing SLAM algorithm framework is studied,the Visual Odometry algorithm is deduced and the loop detection algorithm is introduced for the characteristics of the noncooperative target periodic motion,and the method error is analyzed using the data set.Secondly,based on the vision-based measurement method,aiming at the particularity of spatial non-cooperative target measurement,we present the measurement scheme of the fusion IMU and analyze the advantages of fusion.Then a tight coupling Visual Inertial Odometry algorithm based on single-point RANSAC-EKF is designed and implemented.And it's method error is analyzed.Finally,a simulation experiment platform combining hardware and software was built.The non-cooperative target spin motion was simulated using a turntable and satellite zoom model.The calibrated visual inertial measurement module and the computer simulation tracked spacecraft were used to complete the measurement algorithm operation on the computer in real time to get the simulation results.By analyzing the rotation speed,rotation angle,and cycle loop deviation,the usability of the aforementioned measurement algorithm is further verified.This paper provides a new idea for the relative pose measurement of spatial non-cooperative targets.