INS aided GPS integer ambiguity resolution and real time vehicle attitude determination

It is the crux for high-precision real time attitude determination using carrier phase measurements and the key issue using carrier phase measurement for real time attitude determination is the carrier phase integer ambiguity resolution. Differencing GPS is of significance for GPS integer number cycle of ambiguity, which can eliminate the correlated errors such as the ephemeris prediction, residual satellite clock, troposphere errors etc. Multi-antenna GPS can achieve the attitude of the vehicle, but the precision of the multi-antenna attitude resolution can not meet the requirement of the engineering application. INS can offer the attitude of the vehicle in short time, but the accumulated errors of the INS are gradually increased. It can improve the precision of the vehicle through integrating GPS with INS. Integration with INS, as well as bridging the attitude solution through GPS outages, can also aid the GPS ambiguity resolution process by significantly reducing the search space. Differencing GPS attitude is very noisy but not drift. Therefore, differencing GPS and INS integration is essential for high precision vehicle real time attitude determination. This paper describes a fast and efficient technique for integer ambiguity resolution when INS sensors are available and simulation results illustrate the error analysis of the real time attitude determination. The test results reported that INS aided GPS can obtain the more precision attitude solution of the vehicle. The yaw and pitch angular of the vehicle enhanced nearly 0.02 deg and the roll angular improved 0.15deg.