Ring laser inertial angle encoder

Abstract

Abstract A RING LASER ANGLE ENCODER WHICH MEASURES THE ANGULAR DIFFERENCE IN INERTIAL POSITIONS OF TWO TARGETS AND PROVIDES A HIGHLY ACCURATE, CONTINUOUS, DIGITAL READOUT THEREOF. THE ENCODER COMPRISES A ROTATABLE RING LASER MAINTAINED AT A CONSTANT INERTIAL ANGULAR ROTATION RATE ABOVE A PREDETERMINED THRESHOLD VALUE SUCH AS TO GENERATE A DIGITAL COUND DIRECTLY PROPORTIONAL TO THE ANGLE THROUGH WHICH THE LASER HAS ROTATED, A SCANNER-PHOTOMETER RIGIDLY AFFIXED TO THE LASER AND ROTATABLE THEREWITH ABOUT THE LASER''S ROTATION AXIS, WHICH CONVERTS THE LIGHT INTENSITY OF EACH TARGET SCANNED INTO AN ELECTRICAL SIGNAL HAVING A FREQUENCY PROPORTIONAL THERETO, AND AN ESTIMATOR-DETECTOR CIRCUIT COUPLED TO THE OUTPUT OF THE RING LASER AND THE PHOTOMETER, WHICH ESTIMATES THE CENTER OF EACH TARGET SCANNED AND RECORDS THE LASER''S DIGITAL COUNT (AND FRACTION THEREOF) EXISTING WHEN EACH TARGET CENTER IS SCANNED. THE FIRST TARGET SCANNED IS SCANNED AND ESTIMATED AGAIN UPON COMPLETION OF A FULL ROTATION CYCLE OF 360* FOR PURPOSES OF SELF-CALIBRATION. THE RESULTING DIGITAL COUNTS FOR THE AFOREMENTIONED THREE DETECTIONS ARE COMBINED TO PROVIDE A DIGITAL OUTPUT FROM THE ESTIMATOR-DETECTOR CIRCUIT WHICH IS A HIGHLY ACCURATE INDICATION OF THE ANGULAR DIFFERENCE BETWEEN THE TWO TARGETS OF INTEREST.

Inventors

• 👤 Joseph D Coccoli
• 👤 John R Lawson

Bibliographic Details