Abstract: Spacecraft need to meet the requirements of long standby, long trajectories and high accurate orbit . Generation of carrier rockets from a single inertial platform navigation way, improved redundant guidance system for multiple sets of Strapdown Inertial Measurement Unit. when rocket in the flight of the heaven, a customary group as the main parts control of rocket flight, the other IMU is a hot backup state involved in the redundancy judgment and takes over the main parts work while the main parts failure . This requires site calibration of the initial angle difference between the Redundant Inertial Measurement Unit before the rocket flight. The use of photoelectric goniometer principle measure the installed initial relative angle difference between Redundant Inertial Measurement Unit . We discussed the calibration methods and measurement equipment development program, calculated the measurement result and the proof of principle. The experiments show that the measuring principle is correct, the test results are accurate and strong maneuverability advantages.

Key words: Strapdown inertial guidance, Redundancy technique, Photogoniometer, Calibration