Low-cost GPS/INS integrated navigation algorithm in land vehicle system considering attitude update

The instrument errors in low cost INS can significantly degrade the navigation precision.In this paper,an attitude update algorithm for GPS/INS integrated navigation system on land vehicle is put forward.First,two kinds of attitude observation equations are given based on GPS/INS loose navigation.Then the principle of yaw angle determined by GPS velocity is introduced and the pitch and roll angles of low-cost INS in land vehicle are analyzed.It is suggested that the pitch and roll angles should be kept constant when the errors caused by instrument errors are bigger than themselves.By the actual data calculation,the precision of yaw angle determined by GPS velocity is obtained,and it is shown that,compared with the Kalman filtering based on position and velocity,the new algorithm significantly improves the navigation accuracy.