Velocity Error Analysis of INS-Aided Satellite Receiver Third-Order Loop Based on Discrete Model

Traditionally, continuous model is usually applied to analyze the velocity error of INS-aided GNSS receiver. However, the actual implemented system is discrete. In consequence, the analysis results based on continuous model are iffy. Aimed at this problem, this paper establishes a discrete model of INS-aided third-order carrier loop according to the actual system. Then, the velocity error caused by discretization is investigated and the error mechanism is analyzed. Analysis and simulation results show that the delay of aiding information is the main error source of INS aided GNSS receiver in high dynamic scene. To improve the dynamic performance of INS-aided carrier loop efficiently, the delay of aiding information should be shortened as much as possible.