Optical interferometric navigational instrument

Claim 1

A NAVIGATIONAL REFERENCE SYSTEM COMPRISING THE COMBINATION OF A LASER SOURCE OF RADIATION AND A HIGH RESOLUTION INTERFEROMETER; SAID HIGH RESOLUTION INTERFEROMETER INCLUDING A FIRST OPTICAL CIRCUIT FOR CIRCULATING RADIATION WITH MULTIPLE PASSES AROUND A FIRST CLOSED PATH AND COMPRISING FIRST AND SECOND REFLECTING MIRRORS, AND A FIRST PARTIALLY REFLECTING MIRROR; SAID FIRST OPTICAL CIRCUIT DEFINING THE OPTICAL CAVITY OF SAID LASER SOURCE; SAID LASER SOURCE POSITIONED BETWEEN SAID FIRST AND SECOND REFLECTING MIRRORS; AND A SECOND OPTICAL CIRCUIT FOR CALIBRATION AND FOR CIRCULATING RADIATION WITH MULTIPLE PASSES AROUND A SECOND CLOSED PATH; SAID LASER SOURCE EMITTING RADIATION IN OPPOSITE DIRECTIONS TO PROVIDE COUNTER-ROTATING BEAMS IN SAID FIRST AND SECOND OPTICAL CIRCUITS; THE AREA ENCLOSED BY SAID SECOND CLOSED PATH BEING SMALL WITH RESPECT TO THE AREA ENCLOSED BY SAID FIRST PATH; SAID SECOND OPTICAL CIRCUIT INCLUDING SAID FIRST AND SECOND REFLECTING MIRRORS AND SECOND AND THIRD PARTIALLY REFLECTING MIRRORS LOCATED IN SAID FIRST OPTICAL CIRCUIT; DETECTOR MEANS POSITIONED EXTERNALLY OF SAID FIRST CLOSED CIRCUIT AND OPTICAL MEANS INTERPOSED BETWEEN SAID PARTIALLY REFLECTING MIRROR AND SAID DETECTOR FOR COMBINATING COUNTER-ROTATING BEAMS OF RADIATION IN SAID FIRST OPTICAL CIRCUIT INTO A SINGLE PATH AND TOWARD SAID DETECTOR; SAID FIRST OPTICAL CIRCUIT FOR MEASUREMENT PURPOSES; SAID SECOND OPTICAL CIRCUIT FOR REFERENCE PURPOSES.