Inertial Navigation Aiding by Stationary Updates

Sensor-aided inertial navigation has successfully been used for decades for localization of a roving body. When the rover is known to be stationary, artificial "stationary" measurements (i.e., zero velocity and/or zero angular rate) may be imposed. This corrects the velocity, attitude, and inertial measurement unit (IMU) biases, which decreases the rate of drift of the position and attitude. Implementation requires reliable automated tests to detect periods when the vehicle is stationary. Due to cost concerns, methods that use sensors that are already on the vehicle are preferred. This paper reviews existing stationary detection methods and proposes a new frequency domain approach, using only IMU data, to detect stationarity, with specifications and analysis for land vehicles. The performance of this new approach is evaluated in both theory and practice. In addition, this paper presents analytic and numeric evaluations of the observability of the inertial navigation system (INS) error states with stationary updates. Improvements in localization performance in an INS with stationary detection and aiding is shown experimentally.