Research On Airborne LiDAR Strips Matching

Integrated with GPS, inertial navigation and laser ranging technology, LiDAR(Light Detection And Ranging), as an active geo-measurement system, has such characteristics as little dependent on ground controls, little affection by weather conditions, high automatic and short data processing temporal, and it would probably bring a new technical revolution for surveying, and consequently gives geographers a new challenge(Liu Jingnan,2003).To reconstruct DSM, DEM for true world, the surface need omnibearing scanning by airborne LiDAR. Because of its limited air height and scanning angle, its strip width is limited(less than traditional photogrammetry). When the survey area is very large, several strips are needed to cover the survey area. Keeping definite lateral overlap among strips is very important. That ensures to mosaic the whole survey area image. However, systematic position error and attitude surveying error are different among different strips, so when different strips are calculated, the elevation of the same point in lateral overlap area is not equal. This phenomenon is called Height Relative Offset. The offset makes DTM marriage between tow strips have systematic error and random error. That affects the application of LiDAR in surveying large area.Researching Height Relative Offset, eliminating or weakening systematic error and random error from different strips marriage, analyzing and calibrating airborne LiDAR data, and realizing different strips splicing can provide high accuracy data source for subsequent processing. Although spatial registration for three-dimensional data has developed a lot, LiDAR strips matching method is specific because of complexity of airborne LiDAR system. After summarizing the domestic and foreign scholars' research results, this paper focuses on the registration of airborne LiDAR data with contributions as follows:(1) Analysis and conclusion of the newest research findings of spatial registration for three-dimensional laser scanning data; discussing the applicability of spatial registration for three-dimensional laser scanning data in airborne LiDAR strips matching;(2) Comparisons of three-dimensional laser scanning data matching and airborne LiDAR strips matching in four aspects: hardware system, data acquisition mode, surveying target and overlap region data; define airborne LiDAR strips matching via the difference between three-dimensional laser scanning data matching and airborne LiDAR strips matching;(3) Discussion of the causation about Height Relative Offset; formula derivation for influence of attitude surveying error and system setting angle error to the coordinate of laser point; analysis and analogy calculation for the influence of the two kinds error to the overlap region elevation;(4) Advancing an integrated strips calibration based on data itself, namely, strips matching method based on statistic analysis; formulation for its theory; testing and verifying the method through an experiment using airborne LiDAR data; the experiment result is comparatively perfect; data quality analysis and data error calibration achieve, and data quality is improved.