Joseph E. Killpatrick

The laser gyro

One of the most dramatic recent developments in optical technology is the laser gyro, which combines the properties of the optical oscillator, the laser, and general relativity to produce an integrating rate gyroscope. This gyro measures rotation in inertial space, but does not use a spinning mass as conventional gyros do. Because of the absence of spinning mass, the gyros performance is not affected by accelerations; and it can sense very high rates with great accuracy. Other important advantages of the laser gyro are lack of special cooling, low power consumption, and simplicity of construction.

Inside-Out Horizon Scanner

The theory of performance for a horizon scanner with a reflecting cone and objective lens optical system is presented. The theory and equations describing the optics are given and a method of determining image plane irradiance for any object is shown. The expected performance of the device as a horizon scanner is presented. Experimental results of a horizon scanner model are presented which verify the optical calculations and theory.

An Operating Three Axis Laser Gyro Triad

The laser gyro represents a new generation of attitude sensors with high resolution digital output. Three orthogonally-mounted laser gyros and a direction cosine computer provide a full freedom, high rate strapdown attitude reference system. A dither system is used to compensate for the natural lock-in of the ring laser, and solid quartz construction provides stability and ease of alignment. The unique characteristics of the laser gyro require test equipment and procedures which are different, though simpler, than those for conventional gyros.

Zeeman Discharge Tube Frequency Monitor

A discriminant to frequency stabilize a gas laser has been obtained from a discharge tube in which the gain profile is split by an ac magnetic field. By superimposing a do magnetic field, the discriminant can be centered at any point on the gain profile. By employing feedback techniques, the center of the discriminant can be used to track a laser frequency; the magnitude of the do magnetic field determines the displacement of the laser frequency from the gain maximum.

Laser Gyro Technology

The technology of the laser gyro has advanced to where production of this unique gyro with low cost and high performance is now possible. The technology of lifetime and its factors have now shown operating lifetime capability in excess of 50,000 hours. The performance variation with wavelength and size shows the wide range of parameters which must be considered. The performance of the laser gyro in scale factor linearity varies from 0.1% in the small 9.8 cm 1.15μ gyro to better than 0.0001% in the 43 cm 0.63μ gyro. In similar fashion the null stability and performance also varies over a range of 10°/hr to 0.01°/hr for the same gyros, respectively. Other factors such as gas pressure and multi-mode effects are also discussed.