RT Journal Article SR Electronic T1 Navigation Safety Assurance of a KF-Based GNSS/IMU System: Protection Levels Against IMU Failure JF NAVIGATION: Journal of the Institute of Navigation JO NAVIGATION FD Institute of Navigation SP navi.612 DO 10.33012/navi.612 VO 70 IS 4 A1 Lee, Jinsil A1 Kim, Minchan A1 Min, Dongchan A1 Pullen,, Sam A1 Lee, Jiyun YR 2023 UL https://navi.ion.org/content/70/4/navi.612.abstract AB This study introduces a navigation integrity and continuity algorithm against an inertial measurement unit (IMU) sensor fault within a Kalman filter (KF) that ensures a high level of safety for IMU-integrated safety-critical navigation applications. A representative example of an IMU integrated navigation system is a global navigation satellite system (GNSS)/IMU system. Most previous studies have focused on GNSS faults when evaluating the integrity and continuity of a KF-based GNSS/IMU navigation system, leaving the IMU fault hypothesis unaddressed. Unlike GNSS, which is applied in the measurement update step within the KF, IMU measurements are applied in the state prediction step, which results in different fault propagation characteristics in the user state error compared with those in GNSS. This paper analytically derives the sequential IMU fault impacts on user state errors. Based on this investigation, a KF innovation-based fault detector and protection-level equations are developed, which can safely bound user state errors against sequential IMU fault impacts.