Patent ID: 8275544

Claim:
A system for determining a position of a target comprising: (a) an inertial measurement unit, said inertial measurement unit comprising: a triad of rate gyros mounted to a reference platform, each gyro of said triad of rage gyros having a respective rotational sensing axis; and a triad of accelerometers mounted to said reference platform; (b) a three-axis magnetic sensor mounted to said reference platform for sensing the earth's magnetic field; (c) a position source for determining a coordinate position of the reference platform; (d) a target sighting device, said target sighting device aligned with said inertial measurement unit and said three-axis magnetic sensor, said target sighting device for finding angle coordinates defining a line from said reference platform to said target; (e) a target distance determination device for determining target distance from said reference platform along said angle coordinates; and (f) a state estimation processor for combining data from the triad of rate gyros and the triad of accelerometers with data from the three axis magnetic sensor to generate platform attitude information; said state estimation processor utilizing three axes of said three axis magnetic sensor to correct errors in said platform attitude information; wherein said position of said target is computed based on said coordinate position of the reference platform summed with a position vector having a length according to said target distance determination device and said position vector having a vector direction in accordance with said angle coordinates defining said line from said platform to said target, said angle coordinates in accordance with said platform attitude information.