Application of nonlinear smoothing to GPS/INS integrated navigation system

Abstract

The application of smoothing to integrated navigation system of 4S-Van is considered. 4S-Van is a mobile mapping system, which provides the position information of various objects on the road. For navigation purpose, it has various sensors such as an inertial measurement unit, a GPS receiver and an odometer. It is also equipped with CCD cameras, laser scanners and video cameras, for mapping purpose. The navigation system of 4S-Van is an inertial navigation system, which is aided by GPS and the odometer. Because it can adopt post-processing method for more accurate and reliable result, the nonlinear smoothing is applied. The nonlinear smoothing, which consists of a forward filter, a backward filter and a smoother, is implemented. For the forward filter, the extended Kalman filter is designed, and for the backward filter, the linearized Kalman filter is constituted. In the smoother stage, the results of two filters are combined. The algorithm is applied to experimental data and the obtained result shows the effectiveness and good performance of the nonlinear smoothing.