Lockheed Martin Corporation
TERRESTRIAL LAND AIR AND SEA NAVIGATION SYSTEM

Abstract:

A system can include an inertial measurement unit, a magnetometer configured to measure a magnetic field, and a processing system having an ORSE filter. The processing system can be configured to determine an estimated position based on a change in velocity or angular rate based on data received from the inertial measurement unit, determine a difference between the measured magnetic field from the magnetometer and the expected magnetic field measurement, and determine a state estimate using the ORSE filter by updating a time propagation of state and covariance with a measurement update of the state and covariance. The processing system can be configured to transform a change in velocity, a change in angulate rate, and the measured magnetic field to an Earth-centered inertial reference frame for the ORSE filter.