Research On Carrier Phase Differential GPS, Initial Alignment Of Strapdown Inertial Navigation System And Their Combination

The initial alignment of strapdown inertial navigation system (SINS), carrier phase differential GPS(CDGPS), and CDGPS/SINS have been researched in this dissertation. The major contents can be divided into three parts:In the first part, carrier phase differential GPS is researched. Based on the different applications, CDGPS is divided into two kinds, namely GPS carrier phase attitude determination and GPS carrier phase precision relative position. Aimed at different characteristics of two technologies, the on-the-fly ambiguity resolve methods are researched. First, the theory of GPS carrier phase attitude determination is presented. The GPS attitude determination system is implenmented by least square method based on the constraints of baseline length, geometry relation of antennas, and attitude angles. The geometry interpretation of the baseline length constraint is presented and the attitude angles search algorithm using the pyramid algorithm is proposed. The static experiment, carborne experiment and shipborne experiment are designed to validate the system. It is proved that the accuracy of the GPS attitude determination system can reach the 0.06 (la )for baseline of three meters. Second, aimed at single baseline, the GPS carrier phase precision relative position is researched. The matrix decouple algorithm is improved, and based on the LAMBDA and least square method restricted by linear equations, the changed scale method is proposed to reduce the ambiguity search space. Through the SPIRENT GPS simulator data, true static and dynamic GPS carrier phase data, it is proved that the new method is more effective.In the second part, the initial alignment of laser gyro strapdown inertial navigation system on swayed base is researched. A method named two positions enhanced interrupted alignment is researched and developed. Through the experiment it is proved that the accuracy of the azimuth angle and level angles is 0.1 and 0.06 under the condition that the gyro drift rate bias is 0.05 /h and the accelerometer zero bias is 0.0003g.In the third parts, the CDGPS/SINS is researched. First, based on the GPS attitude determination system developed by ourselves and combined with the low cost SINS, theGPS heading attitude reference system (HARS) aided by inertial is designed and realized. It is proved to be reliable and valid by sea experiment. Second, the GPS attitude determination system is applied to the initial alignment of SINS on moving base. The system error equations are deduced based on the concept of transfer alignment. At last, a new method for instance cycle slips detect and repair is proposed. Through the true GPS carrier phase data the method is proved to be valid.