Error modeling and analyzing of scalar deeply-coupled global navigation satellite system and inertial navigation system

Scalar deeply-coupled global navigation satellite system (GNSS) and inertial navigation system (INS) is a kind of realization method of deeply-coupled navigation system. It is widely used because of its simple structure, robustness and no need to change the basic structure of traditional receiver. However, there was no literature available on the detailed modeling of the INS auxiliary branch. Aiming at this problem, this paper makes an effort on the error modeling and analyzing of the INS branch, which can guide the quantitative analysis of the deeply-coupled navigation system, selection of inertial sensors and parameter optimization. This paper proposed a modeling method including accelerometer zero bias, gyro drift, scale factor error and auxiliary time delay error in Laplace domain (s-domain). Based on the modeling method, the transient response and steady state response of the system has been deduced and the phase tracking characteristic of each error source has been analyzed. Simulation results show that the error modeling is consistent with the simulation results, which provide a theoretical basis for loop performance quantitative analysis and INS device selection.