The Algorithms And Software Development Of GNSS Attitude Determination

Attitude measurement is widely applied in aerospace, military and many other fields, Inertial Navigation System(INS) is the first method introduced to solve this problem. However, because of the inherent defects and expensive price, INS has a variety of problems in practical application. With the development of global navigation satellite system(GNSS), using GNSS to calculate the attitude has become a research hotspot, with a view to the booming of BDS System, it turns to be more significative.The focus of this paper is to calculate attitude information of moving carrier with GNSS data. First of all, research of background and current situation of this field is done, then three important theoretical problems is being discussed in three independent chapter, the three important problems are:(1) The principle and algorithm of attitude measurement. It includes coordinate transformation and the classical algorithm of attitude measurement, on the basis of which, this paper puts forward the rules of attitude coordinate transformation;(2) Short baseline solution of high accuracy. It includes the principle of baseline solution, the error processing of short baseline solution and how to imply Kalman filter to solve GNSS baseline;(3) The constrained OTF integer ambiguity algorithm. It includes detailed study of LAMBDA and modified, constrained algorithm derived from LAMBDA, On the basis of which, this paper combines M-LAMBDA and C-LAMBDA algorithm, by this means, higher fixed rate and efficiency are acquired.Next, on the work of theory study, a program is developed to solve attitude with GNSS data. The program uses C/C++ language under the MFC frame, it can utilize data of both BDS and GPS and with a graphic interface, results of attitude will be presented synchronously.At last, this paper designs some experiments, these experiments are divided into two parts, named testing experiment and comparative experiments, testing experiment is to assess the program’s precision and accuracy with data gathered from moving carrier, which shows the program has high stability and precision of 0.001 rad degree; Comparative experiments focus on the different calculating results between three attitude algorithms and two GNSS systems, from which we can conclude that both BDS and GPS possess ability to solve attitude independently with enough precision and stability, using GNSS data will optimize the result effectively; Different attitude algorithms will bring different results and possess respective applicability.