The Study Of GPS Attidtude Determination And Integer Ambiguity Resolution Technology

As the carrier phase tracking and measurement technology of GPS develop continuously, more and more cost effective GPS OEM cards which have the capacity to output carrier phase measurement are available in the marketplace, which offers the researchers more selectivity to choose GPS hardware and feasible platform to develop non-dedicated GPS attitude determination system. This research has conducted a comprehensive and systematic study for both GPS attitude determination and LAMBDA which is a computationally compact and effective method to resolve GPS integer ambiguity. Firstly, GPS carrier phase observable and differential equation are introduced in detail. The principal of attitude determination based on double difference equation is introduced, followed by the proven of the feasibility to determine attitude of carrier using GPS multi-antenna deployment. The mathematical model of attitude determination is also testified. Detection and repair of cycle slips technology based on redundant double difference observables is introduced, which realized the detection and repair of cycle slips of carrier phase dynamically.Integer ambiguity resolution is the fundamental basis for carrier phase measurement and is also the precondition for GPS attitude determination system. The LAMBDA method is introduced for more effective integer ambiguity resolution. The fundamental theory and the implementation procedure of LAMBDA method is discussed in detail, the key implementation program is given. The simulation of LAMBDA method is implemented by Matlab software, and the input data are six dimensional real ambiguity vectors and its corresponding variance covariance matrix. Based on the simulation results, the computational performance, including computational time consuming, decorrelation and optimization of the search ellipsoid are analyzed. The successful rate of ambiguity resolution is testified, and the qualitative and quantitative analysis based on the experimental data is given. At last, optimizing the LAMBDA method by using the antenna baseline constrains in the GPS attitude determination is discussed, which shortened the ambiguity search time and improved the performance of LAMBDA method in attitude determination system.