Principles and Methods of Electron-Optical Gyroscopy

Abstract

Rotating rigid body gyros are widely used and, due to a number of improvements and refined production technology, they comply with fairly stringent error, size, mass, energy consumption, and other requirements. Minimal error of these gyros estimated by gyrowheel angular velocity fluctuations is about O.Oldeg/hour [1]. According to the data from [2], the error of floating integrating gyroscope can amount to (1−5) × 10−3 deg/hour. In cryogenic gyros with magnetic suspension of the superconducting gyrowheel, the error can be diminished to approximately 10−4 deg/hour. Among the known error sources in mechanical gyros, only static friction and thermal fluctuations of the center of mass (molecular noises) of the rotating gyrowheel cannot be eliminated for fundamental reasons. According to [1], the error due to thermal fluctuations is no less than 10−4 deg/hour. Hence even in the hypothetical situation in which all sources of errors, except molecular noise, are eliminated, the threshold sensitivity of mechanical gyros can hardly exceed 10−4. For present-day and certainly for future autonomous navigation, the sensitivity of mechanical direction sensors and angular velocity sensors is insufficient. In this connection many firms and laboratories study various possibilities of implementing new physical principles in navigation systems. For example, in US new gyros are developed by such firms as AC Spark Plug, Arma, Autonetic, Hoffman Laboratories, Martin, Minneapolis-Honeywell, Motorola, Sperry, etc. [3]. Reviews of new operation principles of navigation systems and some of their possible schemes are described in [1-5] and in the book [6]. Electron-optical gyros are most promising and advanced among the new types of gyros. As examples of such devices, we discuss here only atomic and laser gyros [7, 8].