Research On Real-time Attitude Determination Algorithm Based On GNSS Technology

GNSS technology has been greatly developed since its emergence in the last century,and GNSS attitude determination has attracted attention in various fields as an important component.Compared with attitude determination based on inertial navigation systems,GNSS attitude determination has more significant advantages in applications in various fields,such as low cost,high accuracy,less environmental impact,and errors do not accumulate with time.Therefore,it can provide long-term attitude information for the rigid body,but the satellite carrier signal is easily affected by propagation error and electromagnetic interference,which greatly affects the attitude angle solution accuracy,Therefore,research on designing an efficient attitude determination algorithm and minimizing the impact of errors is even more important.Based on GNSS technology,aiming at the problems in attitude determination,this paper focuses on the following aspects:Based on the positioning observation model,the principle and model of attitude determination are studied.The coordinate system transformation and attitude parameters in the process of attitude measurement are studied.The direct method,least square method,optimal estimation method et.al are studied.Compared with the traditional LAMBDA algorithm,a new algorithm based on the chicken swarm optimization(CSO)algorithm is proposed to complete the fast integer ambiguity search and attitude angle solution.At the same time,the baseline prior constraint information such as length and relative position are used for direct attitude matrix determination.A new algorithm for attitude determination based on orthogonal constraints is proposed to eliminate redundant errors in the solution step and improve the efficiency and accuracy of the solution.This paper also studies the cycle slip error that occurs during the attitude solution,and performs effective correction.Combining the advantages of traditional AFM algorithm that is not sensitive to cycle slip and does not require initial ambiguity,an AFM-assisted attitude determination algorithm is proposed to solve the cycle slip error problem occurred in the solution process,and the results are verified and compared by the direct method and the least square method.Finally,the static and dynamic experiments of single baseline and double baseline are used to test the performance of each algorithm.On the premise of setting up the experimental carrier,the GNSS data received by the stationary and moving carrier platforms are preliminarily processed,and then the attitude angle and accuracy are obtained through the data solution of the each algorithm.The experimental results show that each attitude determination algorithm for different scenes can improve the accuracy and reliability of attitude calculation.