Gravity-gradient-stabilized spacecraft attitude estimation using rate-gyroscope measurements

This paper considers attitude estimation of a gravity-gradient-stabilized spacecraft. In particular, an observability analysis based on the linearized equations of motion, as well as numerical simulations, show that it is possible to estimate attitude using only a rate gyroscope. The ability to estimate the attitude using only a rate gyroscope reduces the need for additional sensing hardware such as sun sensors and horizon sensors. These savings allow for more mass, volume, and power resources to be devoted to scientific payloads, communications, and other operations, which in the context of Earth orbiting microsatellites and nanosatellites, is highly desirable.