Daryl C Stjern

US Patent:

46539182, Mar 31, 1987

Filed:

May 20, 1983

Appl. No.:

6/496606

Inventors:

Daryl C. Stjern - Thousand Oaks CA
Thomas M. Wirt - Canoga Park CA

Assignee:

Sundstrand Corporation - Rockford IL

International Classification:

G01C 1964

US Classification:

356350

Abstract:

A low Q ring laser gyro-dither motor assembly which is responsive to a wide range of frequency components of a drive signal having a randomly varying frequency such that the dither imparted to the gyro is frequency modulated by the drive. The frequency modulated dither varies the lock-in rate of the gyro as a function of the random drive signal to eliminate errors in the gyro output due to lock-in. The drive signal may be random in frequency only or random in both frequency and amplitude to provide the frequency modulation. Fixed frequency modulation may also be employed. The low Q assembly need not be driven at the natural frequency thereof so that a common drive circuit may be employed for a plurality of low Q gyro-dither motor assemblies forming an instrument cluster.

US Patent:

46539190, Mar 31, 1987

Filed:

Jan 31, 1983

Appl. No.:

6/462548

Inventors:

Daryl C. Stjern - Thousand Oaks CA
Frank Daly - Simi Valley CA

Assignee:

Sundstrand Optical Technologies, Inc. - Newbury CA

International Classification:

G01C 1964

US Classification:

356350

Abstract:

A laser gyro for detecting rates of rotating the gyro having a primary dither means for eliminating lock-in at low rates of rotation and a secondary dither means for eliminating nonlinearities in the gyro output when the input rate is a harmonic of the primary dither frequency. The gyro includes a body having a polygonal shaped cavity therein with a mirror disposed at each of the corners thereof to form a closed loop path for two counter-rotating beams. The primary dither includes means for dithering two mirrors 180. degree. out of phase to maintain the cavity path length constant. The secondary dither includes a current dither for differentially modulating the current in each leg of the gyro to randomly null nonlinearities in the gyro output.