LOS Rate Estimation in Inertial Navigation using Landmarks

This paper deals with the problem of estimating the LOS (Line of Sight) rate of the aimpoint of a guided vehicle from certain angle-only measurements. The on-board IMU (Inertial Measuring Unit) provides primary estimates of the vehicle\´s absolute position and velocity. However, the IMU based estimates are not sufficient to guarantee the desired guidance accuracy. We consider the problem where a small number of discrete measurements of the aimpoint LOS angle and continuous measurements of the LOS angle of some nearby landmarks ("track points") are available according to a certain schedule along the trajectory. An algorithm that uses these angle measurements to improve the aimpoint LOS rate estimate is developed. The estimation error of the proposed method is evaluated and illustrated via numerical examples.