The analysis of time synchronization errors in INS/GPS tightly integrated navigation

A large number of theoretical research results show that INS/GPS tightly integrated navigation system has high positioning accuracy, but many researches ignore the time synchronization errors between INS and GPS in theory. Thus, the performance of INS/GPS tightly integrated navigation becomes worse. This paper analyzes the influence of time synchronization errors on tightly integrated navigation, studies the case where the time synchronization errors are not included in the integration filter, which leads to an increased error covariance and the inaccuracy of IMU bias estimation, and proposes the countermeasure in which the time synchronization errors are regarded as a part of the estimation problem in the data integration, besides, uses two different measurements in Kalman filter. Finally, through simulation the feasibility of the method is proved.