Research On High Precision On-orbit Self-calibration Methods For High Resolution Optical Remote Sensing Satellites

In recent years,with the rapid development of space technology,high-resolution optical remote sensing satellite image has become the most important part of highresolution Earth observation system.Geometric positioning information is the basis of the other information in high-resolution satellite remote sensing images.Geometric positioning accuracy of satellite remote sensing images is the core index to measure the advancement and application efficiency of high-resolution satellite remote sensing systems.However,due to the unavoidable thermal and mechanical effects during satellite launching and operation and the necessary camera lens focusing operations,the imaging geometric parameters calibrated before satellite launching have larger errors than the actual state in orbit and can not be applied.Therefore,on-orbit geometric calibration of optical remote sensing satellites using on-orbit remote sensing images and acquisition of accurate internal and external calibration parameters of the imaging system are the key to high-resolution optical satellite image geometric positioning.Aimed at the limited model accuracy and the over-reliance on geometric calibration field in the traditional geometric calibration model,this paper presents a high-precision on-orbit geometric self-calibration method for high-resolution optical remote sensing satellites.On the basis of studying and constructing the more refined geometric imaging model of optical remote sensing satellite taking into account atmospheric refraction and aberration,the geometric self-calibration models and process methods for high resolution area array camera in geostationary orbit and single-linear array/multi-linear array camera in low orbit are proposed respectively.The experimental analysis and method verifications are carried out by using actual remote sensing images and simulated remote sensing images.The innovations can be summarized as follows:(1)A geometric imaging model of optical satellite considering the atmospheric refraction and aberration correction is proposed.It can reflect the mapping relationship between the image point coordinates and the ground point coordinates of high resolution optical remote sensing satellite image more precisely.It is the theoretical basis of high accuracy on-orbit geometric self-calibration.The formation mechanism of the aberration error and atmospheric refraction error in optical satellite earth observation imaging is systematically studied and discussed.The error characteristics of the aberration and atmospheric refraction errors are quantitatively analyzed.On this basis,the correction models of aberration error and atmospheric refraction error are constructed.Based on the above research,this paper refines the traditional geometric imaging model of the optical satellites,introduces the correction model of the aberration and atmospheric refraction errors into the traditional geometric imaging model,constructs the more refined geometric imaging model,and verifies the feasibility of extending the RPC model of this model,which lays a foundation for the construction of the subsequent geometric self-calibration model and the determination of the imaging planning scheme.Thus,the theoretical basis is established.(2)The process and method of on-orbit geometric self-calibration of the highresolution geostationary array camera are proposed,which provides a new idea and method for the future geometric calibration of super high-resolution geostationary optical satellites.In this paper,the on-orbit geometric calibration and geometric slef-calibration methods of high-resolution area array camera in geostationary orbit are discussed and analyzed in detail.The rigorous physical imaging model of the geostationary array camera is constructed,and the error sources causing geometric positioning errors are listed and analyzed on the basis of the rigorous physical imaging model.Aiming at the problem of high correlation between geostationary orbit geometric positioning error sources and low saliency of some parameters,this paper adopts two-dimensional directional angle model to carry out on-orbit geometric calibration based on the geometric calibration field,and proposes the corresponding control point matching and calibration parameters calculation methods.At the same time,a simplified and rigorous physical measurement model is constructed,and an on-orbit geometric self-calibration method based on the intersection constraints and the calibration parameters caculation method are proposed.The influence of different overlapping styles on the calibration accuracy is also analyzed.(3)The process and method of on-orbit geometric self-calibration for optical linear array satellites are proposed,which effectively reduces the dependence of traditional geometric calibration methods on the geometric calibration field.Aiming at the over-dependence of the traditional on-orbit geometric calibration methods on the large-scale and high-precision geometric calibration fields for the optical linear array satellites,the research on on-orbit geometric self-calibration methods for the optical single/multi-linear array optical satellites is carried out.The aim is to reduce the dependence of the geometric calibration process on the absolute constraints by relying on the relative constraints of the multi-view stereo images.At the same time,it can achieve the accuracy level that not inferior to the traditional geometric calibration method.Based on the analysis of imaging errors of the multi-view stereo images,the geometric selfcalibration models based on two/three-view stereo images are proposed in this paper.Besides,the geometric self-calibration process and imaging planning scheme for single/multi-linear array optical satellites with atmospheric refraction and aberration errors taken into account are studied.The reasonable imaging planning and selfcalibration process can effectively acquire self-calibration data in time and efficiently according to the maneuvering imaging capability of each satellite,and effectively reduce the dependence on the geometric calibration field.In view of the above research contents,this paper uses the simulation and real data of satellites such as Zi Yuan 302,Gao Fen 2,Gao Fen 6,Gao Fen 4 and Gao Fen 1 to verify and analyze the proposed methods.The experimental results show that the more refined geometric imaging model and geometric self-calibration model considering the atmospheric refraction and aberration errors proposed in this paper can effectively achieve high-precision geometric calibration for the high-resolution geostationary area array camera and LEO single/multi-linear array camera,while effectively reducing the dependence on the large-scale and high-precision geometric calibration field.