Carrier Phase Diff-positioning Technology In ITS

Vehicle positioning and navigation problem is an important part of Intelligent Transportation System (ITS), and it has great practical significance and value. The carrier phase positioning technology is one of the key technologies in the Intelligent Transportation Systems; it is produced and developed for the exaltation of GPS positioning accuracy. Differential relative positioning of GPS (DGPS) is gradually perfected.. On the basic above, this has enhanced the precision of GPS positioning to a great extent, and also widened the application range of GPS.In this paper, the main work is discussing the method of carrier phase positioning and differential system. The part of inter ambiguity resolution is emphatically discussed. First, this paper introduced the basic components and features of the Global Positioning System (GPS) and analyzed various errors on the positioning accuracy. We discussed the basic observation model and the principle of static and dynamic positioning and compare the pseudo range differential and carrier phase positioning accuracy of the two basic measurements. Second, we elaborated mathematical models and working principle of the GPS carrier phase differential positioning system, and used simulation to determine its positioning performance. Third, we discussed positioning of the carrier phase integer ambiguity and analyzed common methods of static and dynamic variety of ambiguity resolution. Finally, this paper focused on LAMBDA (Least-squares AMBiguity Decorrelation Adjustment) method and has given the process of positioning algorithm and experimental simulation. We can clearly see the result that it improves accuracy of real time positioning.