Vrs France-based Gps Measurements

It's been more than 20 years since GPS surveying technology was applied surveying field, the technologies has developed greatly, surveying mode experienced static surveying semi static surveying and dynamic surveying, and the position precision has also achieved mm level. All these advantaged GPS technologies can apply not only routine surveymg such as geodetic surveying control surveying and engineering surveying and so on, but also city planning GIS municipal construction traffic management machine control project watching vehicle navigations police and fire protection agricultures weathers zoology and environment protection and so on. convenient surveying modes high precision and wide applying field make GPS surveying to a promising research direction in the mapping subject.Multi-reference stations GPS surveying is becoming a popular subject which is being researched and applied. The paper will discuss one of these technologies that is GPS surveying based on VRS (Virtual Reference Stations). First of all, the paper explained the necessity of VRS research from the points such as the development of GPS surveying and multi-reference station technology today's need for surveying. Secondly, it explained briefly the basic principle of GPS surveying based on VRS and some pivotal technologies. Thirdly, it specified multi-error resource problem which need be resolved in VRS surveying. Fourthly, the paper deducted interpolation methods getting corrections methods, and established mathematics model of VRS based on the principle of VRS with the double difference between revivers and satellites, then resolved baseline resolutions basic quality assess. In contrast with Trimble VRS model, the paper telled briefly Trimble VRS model, and compared with them, so pointed out the advantages and disadvantages of the paper VRS model. Fifthly, the paper specified the technology design and reliability of VRS. Lastly, the paper testified the position precision initialization time and reliability of VRS with a foreign test for VRS.