On range and attitude estimation

Two algorithms to support an airborne, gimballed, electro-optical sensor are described. They have been designed for “Litening”, a new targeting and navigation pod, which has been developed by Rafael. A full inertial measurement unit (IMU), capable of measuring linear acceleration and angular velocity, in three orthogonal axes, is mounted in the inner-most gimbal. The first algorithm estimates the attitude of the sensor line of sight (LOS). This estimation, accompanied by on-line sensor calibration, is carried out by a multi-state, multi-measurement Kalman filter, which is integrated within a strapdown navigation system. The second algorithm deals with the range (from a ground target) estimation. A new, linear (!), range estimation problem is formulated. Due to available data, range dynamics is presented as a linear, time varying system. A linear measurement equation, based on an appropriate error model, is obtained as well