Study On Theory And Algorithm Of The In-flight Geometric Calibration Of Spaceborne Linear Array Sensor

In-flight geometric calibration is a crucial technique and an essential processing step to obtain spatial remote sensing imagery with great geometric quality and high positioning precision. It can effectively eliminate both system error and random error caused by satellite platforms and sensor systems, and therefore, provides great assurance to both image positioning and image application.In this thesis, in-flight geometric calibration theories and techniques of spatial linear array CCD sensors were systematically researched. The main work and innovations are listed as follows.1. Imaging characteristics of current spatial linear array CCD sensors were analyzed.Both ALOS/PRISM and ZY03 three-line-array satellites sensors were introduced, and the geometrical calibration contents and methods of space-borne linear array sensors were compared and summarized.2. Two types of rigorous geometric model were proposed, whose origins were set on sensor center and satellite body respectively. And subsequently, two specific rigorous geometric models were constructed for geometric calibration of space-borne linear array CCD sensors.Both SPOT-5/HRS and ALOS/PRISM image data sets were used in the experiments, the experimental results proved the feasibility and precision of the proposed model.3. A self-calibration model was proposed for space-borne linear array CCD sensors. And for the model, physical factors such as CCD pixel size transformation, focus transformation, aligning CCD position transformation, camera optical distortion and so on, were integrated to correct pixel displacement of satellite images. And the rationality of the additional parameter was validated.4. Rigorous geometric model, interior orientation self-calibration model and exterior orientation expressing model were analyzed. And based on the analysis, multi-mode linear array sensor self-calibration block adjustment models were constructed to provide theoretical models for in-flight geometric calibration of space-borne linear array sensors.5. According to the stable characteristic of satellite orbits, Direct Calibration Model (DCM) of exterior orientation parameters was proposed. The structures of error equation and norm equation of the model block adjustment system were analyzed. And the solution efficiency and direct geo-referencing precision was improved. Experimental results proved the feasibility of applying DCM block adjustment model to the in-flight calibration of spatial linear array sensors.6. For space-borne linear array sensors, both simulation and truly obtained dataset were used for experiments of multi-mode linear array sensor self-calibration block adjustment. The reasonability of exterior parameter describing models, interior self-calibration parameter setup and point relaxation computation were comprehensively validated. Calibration precisions of Piecewise Polynomial Model (PPM), Orientation image Interpolation Model (OIM) and DCM self-calibration block adjustment model were analyzed and compared. And the three models were proved by experiments to be useful for in-flight geometric calibration of space-borne linear array sensors.7. Abroad geometric calibration experience of space-borne linear array CCD sensors was studied. Focusing on the content and method of geometric calibration, a few rational considerations to the construction of geometric calibration test-field in our country were proposed.