Mechanical rate gyroscopes have become ubiquitous in almost all types of systems where angular velocity measurements are desired. Until fairly recently, a lack of competition has made the mechanical gyro a virtual necessity in many measurement and stabilization applications.However, in the past few years, solid-state rate sensors have begun to infiltrate markets previously controlled by the mechanical sensor. In many applications fluidic and Coriolis force rate sensors can offer improved performance and/or reduced cost. While these devices overcome many limitations of their mechanical counterpart, each type has unique operational characteristics.Fundamentals of operation for each type of sensor are discussed in this paper. Theoretical and practical operating features of each type are discussed. Typical specifications for present -day sensors are presented, along with an application for which solid state gyros are ideally suited.