Attitude Measurement System Based On Multi-frequency Galileo Data

The research on attitude measurement using GNSS carrier phase signals is a new direction of studies. In this paper,Galileo system as an example,studied the system of attitude measurement on multi-frequency observations ofsatellite carriers.The technical characteristics and key technologies are summed up and has been refined and optimized to improve the speed and accuracy of attitude measurement.First gives the Galileo observation models of attitude measurement system, summed up the concept of the linear combination of multi-frequency carriers and makes a complete error analysisthe of the Galileo attitude measurement system , this is a part which provides a theoretical basis for the work behind.Severl methods using multi-frequency carrier phases to fix the initial carrier phase ambiguity are researched.The TCAR method is simple,but the overlapped and cumulated observation noises make its success rate is difficult to guarantee.A small ambiguity search space has been introduced in the second step of TCAR method which has the lowest success rate and the whole success rate of the TCAR solution algorithm is raised.And the constraint method is proposed based on the nowadays available conditions of multi-frequency carrier-observations.It chooses two different frequency carrie phase form a wide-lane measurements. Then it will make sure of the wide-lane ambiguity by using existence constraint factors to limit the ambiguity search range, by eliminating the incorrect ambiguity candidates through four methods.Finally, the integer ambiguity on the single-frequency carrier phase could be resolved. Compared to traditional TCAR, this algorithm wins a higher success probability of integer ambiguity determination. The simulation result indicates that this method is feasible and is suitable for single epoch ambiguity determination.Cycle slip detection and repairs using multi-frequency data is also studied.Melbourne-Wübbena method is a cycle slip detection method which is suitable for multi-frequency observations , double-difference carrier phase measurements and suitable for static and dynamic use. But it can not detect the small cycle slips. So,the Melbourne-Wübbena method of Cycle slip detection and repairs has been improved to make sure of detecting and repairing any number of weeks of the cycle slip.An improved TRIAD algorithm based on weighted vector sum for spacecraft attitude determination was studied to improve the accuracy. Discussed how to improve the attitude accuracy by using a number of frequency carrier phase getting the more accurate baseline vector base on the characteristics of multi-frequency observations of nowadays satllites system. And described and narrated the simulation process of spacecraft's multi-antenna flight trace.At last, verified the Galileo attitude measurement system by emulators and all aspects of the study's improvement.