Study On Attitude Determination Of Kinematical Carrier Using Carrier Phase Of GPS System

It's a new research field to determine the attitude of kinematical carrier using measuredcarrier phase of Global Positioning System (GPS). This thesis investigates the attitudedetermination using carrier phase with an emphasis on theoretical aspects and algorithms.The implementation of determination system is also discussed.An attitude determination system with two GPS receivers is suggested and key techniquesof the system are summarized. The system consists of three vital stages including dataacquisition and processing, ambiguity determination and attitude determination. Theflowchart of system implementation is also presented.In the stage of data acquisition, GPS receivers output in binary format. The necessary datafor attitude determination are extracted, including dual-difference of carrier phase,coordinates of receivers and satellites in WGS-84 coordinate system. Several detecting andprocessing methods of cycle-slips in the data are discussed. Results show that polynomialfitting method and trinal-difference method are feasible.In the stage of ambiguity determination, the key problem is to search integer ambiguity.Also, this is the key of the whole attitude determination system. First, most of the availableambiguity determination methods are analyzed and summarized into two steps, initialvalue estimation and ambiguity determination. Then, the method using kalman filteringand LAMBDA algorithm is chosen. LAMBDA is a two-step algorithm, includingambiguity de-correlation and ambiguity searching. A branch-and-bound method isproposed to substitute the exhaustion method to search ambiguity. Simulation result showsthat the efficiency is greatly improved.In the stage of attitude determination, three relevant coordinate systems are introduced.They are the world global system, the body frame system and the local level system. Themethod to evaluate the accuracy of the estimated attitudes is suggested.In all the three vital stages, algorithms are programmed and verified using simulated data.Furthermore, based on the theoretical research, the attitude determination system isimplemented using SUPERSTAR OEM receivers manufactured by a Canadian company,NovAtel Finally, a field test in performed in Panda Electric Company to test and verify thesystem.