Integrity Monitoring of Integrated Satellite/Inertial Navigation Systems Using the Likelihood Ratio

Global Navigation Satellite Systems (GNSS) have the ability to fulfill the navigation accuracy requirements of most applications. The systems do however lack continuity and integrity to meet the requirements of high precision navigation applications. The use of a combination of Inertial Navigation Systems (INS) and GNSS information do however show promising results in fulfilling these requirements. Methods for monitoring the integrity of integrated INS-GNSS systems are investigated. Integration of INS and GNSS is usually accomplished using a Kalman filter for recursive estimation of the parameters of interest. The residual used for integrity monitoring is the Kalman filter innovation. The innovation signatures of different types of faults are analyzed. Since two of the most likely types of faults in an integrated solution are INS sensor bias shifts and satellite range bias drifts or jumps, these additive types of changes are studied in more detail. Taking the approach of hypothesis te..