Research on DGPS Method in the Field of Resources and Environment Remote Sensing
DGPS在资源环境遥感中的应用方法研究

In order to efficiently and accurately measure geographic locations of ground truth features in the field of resource and environment remote sensing using economical and easy operational GPS instrument, the following experiments were carried out using C/A code pseudo_distance differential GPS instrument (DGPS). Firstly, the effect of base station's geo_center reference coordinate (WGS84) on location accuracy was evaluated. Secondly, a point was differentially located with a known trigonal control point as base station site and a three parameter Molodensky Model as datum transformation model between WGS84 and Beijing 54. On this point, we then established a temporal base station, which was used to measure the aimed ground truth features in the test site. The location accuracy attained by this route was evaluated as well. It was found that DGPS measured map is of highly absolute accuracy (2\_5m), and this absolute accuracy does not change with the minor error of geo_reference coordinate of the base station. It is a practical method to measure and establish a new temporal base station, which can be used to carry out the real measure work in the test site. The location error of this method is far under one image pixel size (25m) with one geo_referenced TM image as evaluation reference. However, if the trigonal control point and datum transformation model do not exist, the result of base station single point absolute location can be used as reference coordinate, the measured result of which can be geo_referenced to remote sensing image using some tiepoints on the basis of the first result above. Because this method does not need to know the geo_reference coordinate and datum transformation model, it's a ecnomical and practical method for resources and environment remote sensing.