Patent ID: 8209140

Claim:
A method of cooperative calibration of a heading sensor, comprising: (a) providing a primary device including a heading sensor that provides measurements of heading, an optical sighting system with a fixed relative alignment to the heading sensor, a position sensor, a processor, memory and a communication link; (b) providing a secondary device including a position sensor and a communication link; (c) aiming the primary device's optical sighting system to acquire the secondary device; (d) measuring with said heading sensor a sensed heading and a sensed pitch from the primary device to the secondary device; (e) measuring with the respective position sensors the positions relative to a fixed Earth coordinate system of said primary and secondary devices; (f) receiving at said primary device via the communication links the position of the secondary device; (g) from said positions of said primary and secondary devices, calculating with said processor a true heading and a true pitch from the primary and secondary positions; (h) subtracting with said processor the true and sensed headings to form a heading calibration angle and the sensed and true pitch to form a pitch calibration angle; and (i) recording the heading calibration angle and the pitch calibration angle in said memory to compensate further heading and pitch measurements.