Applying GPS Time-Differenced Carrier Phase velocity estimation for Calibration of LDV/INS Integrated Navigation Systems in land vehicles

Abstract

The laser Doppler velocimeter (LDV) is integrated with inertial navigation systems (INS) to form an integrated navigation system to acquire the land vehicle’s orientation, velocity, and position. As an integrated navigation system, the calibration items, including scale factor error of the LDV and the installation angle error between the INS and the LDV, should be well calibrated; otherwise the accuracy of navigation performance will be seriously affected. The paper represents a method about applying time-differenced carrier phase observations to deliver accurate reference velocity for calibration instead of differenced GPS (DGPS) or precise point position (PPP). The differential carrier phase between successive GPS epochs eliminates the effort of ambiguity and it is able to achieve millimetre-level relative velocity accuracy within minutes. In order to make up for the insufficient of calibration time, a iteration method is implemented for fast convergence. The navigation experiment shows that the calibrated LDV/INS navigation system can reach 34.7m/25.5km in horizon and 4.8m/25.5km in vertical.