A Study On Positioning Theory Of Line-Array CCD Imagery Based On Quaternion

Line-array CCD Images are widely used in positioning of remote sensing imagery. However, the orientation parameters of traditional linearization collinear equation are highly correlated because of such factors as big flying height, small angle of coverage, narrow light beam and so on, and thus, are fairly difficult to gain steady and precise solutions. This dissertation makes a comprehensive study on the subjects related to photogrammetric positioning of the line-array CCD images based on quaternion, which includes the solution of ill-posed problem, describing exterior orientation elements by quaternion, bundle block adjustment based on quaternion, etc. The followings are what we have done in this dissertation:1. Making a comprehensive study on the subjects related to photogrammetric positioning and close-form solution of absolute oritentaion based on quaternion, putting forward a new close-form solution method based on dual quaternion. Dual quaternion is introduced into absolute orientation to describe rotation parameters and translation parameters, and experiments were done in all these methods.2. Analyzing the reasons theoretically to ill-posed problems which are appeared in the process of solving exterior orientation elements, and putting forward an improved bias-estimation method to compute the exterior orientation elements of line-array CCD images in the aspect of computation methods.3. Using quaternion to describe the attitude elements of line-array CCD images in the aspect of model selection, putting forward an improved EFP model of exterior orientation elements based on the idea of Equivalent Frame Photo, and doing some exterior orientation experiments through the improved EFP model.4. Gaining the quaternion attitude elements of any scan line through the method of Spherical Linear Interpolation of quaternion, when quaternion is used to describe the exterior orientation elements of the first and the last scan line of a line-array CCD image, putting forward a SLERP model for exterior orientation elements, and then doing some exterior orientation experiments by SLERP model. It successfully avoids a great deal of computation of trigonometric functions and the potential unstable factors, provides a new technique for exterior orientation of line-array CCD image.5. Considering that there are some coordinate blunders in Ground Control Points (GCPs), a blunder detection method is used in the process of exterior orientation by the combination of quaternion improved EFP model and quaternion SLERP model, doing some positioning experiments by space intersection, and the experimental results verified the reliability and stability of these methods. 6. The quaternion-based bundle block adjustment of line-array CCD images is studied in this dissertation. Favorable initial values of computation parameters in bundle block adjustment are not required by this method, and the initial values can be assumed to zero. Experimental results indicate that the plane precision is very high, while the height precision is less admirable.