Study On Integer Ambiguity Resolution Algorithm With The Plane Constraint

In GPS positioning, integer ambiguity solution is the key to achieve precise positioning. it has great significance to fast and accurate ambiguity resolution to improve positioning accuracy and reduce the positioning time. It can be improved that the reliability of the single epoch ambiguity resolution by adding constraints. Therefore, this thesis puts forward an algorithm about single epoch solution of double difference ambiguity with the plane constraint. Finally,we can verify the feasibility of the algorithm and analyses the calculative effect of this model by experiments.This thesis mainly contains the following aspects:Firstly, on the basis of the basic principle of GPS measurement, introduces the GPS relative positioning technology, analyzes the positioning principle and characteristics of single difference and double difference in GPS relative positioning, compares the characteristics and applications of the linear combination of multiple phase observation. The technique of preprocessing the GPS observations has been introduced in order to prepare for the subsequent experiment scheme design and satellite data processing.Secondly, the theory and the method of the ambiguity resolution are introduced in this thesis, and several typical ambiguity search technique such as the ambiguity function method (AFM), least squares ambiguity search technique (LSAST), least square ambiguity decorrelation adjustment (LAMBDA) are discussed. The advantages and the disadvantages of these methods are compared in this thesis. Using the least squares algorithm to solve the floating solution of ambiguity and Searching for integer ambiguity by using LAMBDA method..Finally, In GPS single epoch positioning because of the condition number is limited, the floating precision of ambiguity least-square solutions is very poor, integer ambiguity is difficult to be correctly fixed, in this thesis, by adding the space plane as constraint condition, using the constraint relations of coordinate parameters and ambiguity parameters, to improve the calculation precision of floating ambiguity, reduce the searching space of the integer ambiguity. Using a variety of solution combined with constraint condition on carrier phase integer ambiguity of single epoch solution, and by the measured data of different base station, verify that the improvement effect of ambiguity solution under the plane constraint conditions. In data processing, using the advantage of combination observation in calculating integer ambiguity. First, wide lane combination ambiguity of double difference can be fixed. Then, using the wide lane ambiguity and constraints condition to fix L1 and L2 ambiguity-respectively. Finally, realizing the single epoch positioning, and from multiple perspectives to validate the effectiveness of the constraint condition. After validation constraints feasible, further attempts to dynamic positioning on double station. By increasing the reference station, the total number of observations is effectively increased. Using the baseline closed relationship between the base station and moving station appropriately, Take the calculative results of static base station into kinematic positioning to improve the su ccess rate and reliability of integer ambiguity fixing, and it is conducive to the final coordinates correction.