INTERFEROMETRIC OPTICAL SYNCHRO FOR ALIGNMENT TRANSFER

SPACE WEAPONS FIRE CONTROL REQUIRES THAT THE FINAL WEAPON AIM POINT BE PREDICTED WITH A PRECISION IN THE TENS OF NANORADIANS RANGE. THIS REQUIRES THAT THE ANGULAR COORDINATES OF THE TRACKING OR DESIGNATING SEEKER BE MEASURED, TRANSMITTED AND REPEATED WITH SIMILAR PRECISION. CLASSIC APPROACHES FOR MAKING HIGH ANGULAR RESOLUTION MEASURMENTS INCLUDE MAGNETIC SYNCHROS (RESOLVERS) AND OPTICAL SHAFT ENCODERS. THESE FALL SHORT IN TERMS OF THE REQUIRED PRECISION BY A SUBSTANTIAL MARGIN, AND IN ADDITION, IN THE CASE OF THE SHAFT ENCODERS, THEY BECOME UNWIELDY AT THE HIGH PRECISION LEVELS. OPTRA PROPOSES TO DEMONSTRATE A ROTATION MEASUREMENT TECHNOLOGY OF GREATLY IMPROVED PRECISION AND RESOLUTION. THE TECHNOLOGY IS BASED ON THE USE OF A 2FREQUENCY HENE, HETERODYNE LASER AND REMOTE INTERFEROMETERS LINKED BY MONOMODE POLARIZATION HOLDING FIBERS. IN ADDITION TO ITS HIGH RESOLUTION THE MEASUREMENT IS UNAMBIGUOUS WITH DIRECTION, AND ANGULAR RATES CAN BE LARGE. THE SENSOR PART IS COMPACT AND WHOLLY PASSIVE, THEREFORE IT IS UNABLE TO GENERATE EMI OR BE AFFECTED BY IT, AN IMPORTANT CONSIDERATION WHERE WEAPON FIRINGS TAKE PLACE OF WHERE HIGH MAGNETIC FIELDS DUE TO HIGH CURRENT TORQUERS ARE PRESENT.