Unscented Kalman filtering for ultra-tightly coupled GPS/INS integration

Ultra-tight integration is increasingly becoming important due to its numerous advantages in terms of the robustness in the high dynamics and the immunity to the jamming and interference. Because of these advantages, the next generation of integrated GPS/INS navigation systems can be based on the ultra-tightly coupled configuration. This paper proposed a unscented Kalman filter design approach for the ultra-tight GPS/INS integration. Based on this structure, INS error models are discussed. Through analyzing the relationship between GPS (I&Q) measurements and INS (position and velocity) states, a I/Q estimate method is proposed. Finally, the design method of UKF for the ultra-tight integration system is proposed. Different experimental scenarios are design to evaluate the performance of the UKF based ultra-tight system. The experimental results indicated that the performance of the UKF based ultra-tight integration system is improved.