Study On Attitude Determination Method Of Distributed Moving Warship OTHR System

The development of the communication technology, the data fusion technology and the new system radar speeds the development of radar netting. Thereforce,distributed moving platform ground wave OTH radar has great development potetinal and space. This radar platform system is the coherent system, so, in this distributed platform system, relative distance and attitude relation between carrier and carrier play an important role on system performance. Real-time measurement of ralative distance and attitude is important content in this subject.It's a new research field to determine the attitude of kinematical carrier using singnal of Global Positioning System(GPS).This thesis investigates the attitude determination using carrier phase with an emphasis on theoretical aspects and algorithms.An attitude determination system consists of three vital stages including data acquisition and processing,ambiguity determination and attitude determination.The flowchart of system implementation is also presented.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 available ambiguity determination methods are analyzed and summarized into two steps,initial value estimation and ambiguity determination.Then,the method using least square filtering and LAMBDA algorithm is chosen.LAMBDA is a two-step algorithm,including ambiguity de-correlation and ambiguity searching.GPS carrier Phase Positioning has a higher accuracy than code Positioning,assuming the integer ambiguity is correctly fixed. With the rapid development of the carrier phase differencing technique and digital signal processing hardware, it is possible to implement real-time processing of GPS based attitude determination system. Real-time attitude determination is derived from extremely precise differential carrier phase measurements among multiple GPS antennas mounted on the vehicle. In this dissertation,the theory and method of GPS based attitude determination techniques are studied,and the algorithm is deducted in detail,real-time attitude determination system scheme is also proposed.