Estimation of errors in the integration of GPS and INS

Estimation of errors in the integrated navigation system that consists of a very low-grade inertial measurement unit (IMU) and a single antenna GPS measurement system is studied in this paper. Observability properties of the errors are investigated with a control-theoretic approach. The uncertainties in attitude, gyro bias, and GPS antenna lever arm are shown to cause errors in the estimates of position, velocity, and accelerometer bias. Changes in the acceleration of vehicles improve the estimates of attitude and gyro bias. Changes in the angular velocity enhance the lever arm estimate. Both the motions of translation and constant angular velocity have no influence on the estimation of the lever arm. A car test was performed to confirm the observability analysis.