Research On On-The-Fly GPS Ambiguity Resolution And Its Applications

Real Time Kinematical Global Positioning system(RTK GPS) carrier phase relative position is widely researched and used for its ability of high precision. Ambiguity resolution is the key to precise positioning applications with GPS carrier phase measurements.The principle and the method of the GPS carrier phase measurement positioning are introduced in the thesis firstly,and the positioning technology by using carrier phase allocation technology is introduced further. Secondly, the mathematic model of the carrier phase measures are discussed, including several kinds of differencing equations and the mathematic models for reducing position errors. The technique of preprocessing the GPS observations has been introduced. The theory and the method of the integer ambiguity search technique are introduced in this thesis,and several integer ambiguity search techniques such as the AFM(Ambiguity Function Method),LAMBDA(Least-Square Ambiguity Decorrelation Adjustment) , FARA(Fast Ambiguity Resolution Approach) and FASF(Fast Ambiguity Search Filter) are discussed. The advantages and the disadvantages of these methods are compared in this thesis. This thesis focused on the establishment of the vehicle track by using GPS. Based on the current statistic model of the vehicle,the kalman filter to process GPS data is set up. The road information that can restrict the vehicle track is introduced. The idea is to modify the one-step estimated value using the restricting information so that the filter results can be improved. The float ambiguity estimated by kalman filter and integer ambiguity resolution based on LAMBDA method is afforded.Based on the theoretical analysis, the experiment has been completed, and improved the effectiveness of the algorithm. At last of the thesis, the whole research work is summarized and the further research aspects are pointed.