Pseudolite Augmentation for GPS Aided Aerial Photogrammetry: An Analysis of Systematic Errors

摘要

GPS has been widely used as a geo-referencing tool in aerial surveying. However, the accuracy and availability of GPS positioning cannot meet the stringent requirements of large-scale photogrammetry. Ground-based pseudolites can strengthen measurement geometry for GPS based airborne geo-referencing systems. As a result, positioning accuracy and reliability can be improved, especially in the vertical component. However, as pseudolites are comparatively close to receivers, some challenging issues in systematic error analyses and modeling need to be further investigated. In this paper, the major systematic errors related to pseudolites, such as tropospheric delay, multipath and pseudolite location errors are analysed, and their impacts on the performance of an integrated GPS/Pseudolite airborne geo-reference system are presented.