Navigation Error Analysis in Strapdown Inertial Navigation

One of the most important characteristics of an inertial navigation system is its navigation accuracy, which is directly related to the measurement errors of the inertial measurement unit (IMU). This chapter analyses the relation between the IMU error and the navigation error in the strapdown inertial navigation. It introduces the terminology, origin, and characteristics of some of the major error sources. Error sources in navigation can be categorized into three groups: IMU errors, initial calibration errors, and numerical errors. Assembly errors mainly come from the shift of the mounting direction of individual inertial sensors from their ideal orientations. The position error will exceed a meter of error within a few seconds of navigation with unaided consumer grade IMUs. Tactical grade IMUs have the capability of attitude measurement with reasonable errors and are able to conduct short-term navigation, with navigation accuracy on the order of meters within 30 seconds of strapdown inertial navigation.