Research Of Algorithm For GPS Attitude Determination System Based On Carrier Phase Differential Technique

Attitude determination by using GPS carrier phase is a new area of application of GPS recently. Comparing with the traditional attitude determination methods by INS (inertial navigation system), the information of position, velocity and attitude can be obtained by GPS attitude determination system, also do not divergent with time. And this advantage makes GPS being good at attitude determination than others. Now the method has being used in the fields such as route navigation, precise landing and automatic driving and so on. The key technologies of GPS attitude measurement system have been studied in this paper, which give a basic research on the extending the application of GPS technology.Based on the research of the carrier phase determination technology and the baseline attitude information solution technology, introduced the GPS carrier phase measurement and positioning principles, including the observations of carrier phase measurements, observation equations and theirs linearization, the principle carrier phase relative positioning, etc, confirmed the way of attitude measurement, on this basis leads to the basic principles of Attitude Determination, the main error sources which effect on the precision of the system have been analyzed, which laid a foundation for the following algorithm to vehicle attitude determination. During attitude determination using GPS carrier phase, the determination of baseline vector is necessary, and the key work is to ensure the accuracy of carrier phase information. Fast and accurate access to the initial carrier phase ambiguity is the key factor to obtain high-precision positioning, which is the key issue of GPS attitude determination. According to the comparation and analyzation of common solution methods of integer ambiguity, a simulation result has been given in this paper to prove the method which based on the integer ambiguity solution method of the attitude measurement system has been determined is efficiency.Cycle slip is a peculiar problem in the GPS carrier phase measurement process, and a key issue of GPS attitude determination. If the cycle slip occurring time and value can be detected, the observation value will be easier corrected at the right epoch, and restore the correct count. By analyzing and comparation the common methods of cycle-slip'detection and repairation, a good solution method of multi-valued problem of the ionospheres remnant method has been given, a simulation result has given to prove the new method is efficiency and feasible.In the process of GPS attitude determination, there are many types of navigation information need to solve, to solve each kind of navigation information needs to the same data process and calculation repeatedly, the process is very cumbersome, at the same time, a software platform is also needed which can deal each kind of navigation information and corresponding data processing with module processing. In the last part of the paper the GPS attitude determination software system has been designed based on MFC. A friendly platform has been shown on the computer, and the key algorithms of GPS attitude measurement can be simulated and verified, which not only raising the solution speed but also showing a friendly simulation platform for the further researching of GPS attitude measurement system.