Patent ID: 8156806
Filing Date: 2012-04-17
Classification: G01C,G01P

Abstract:
1. A system for determining acceleration and rotation of a spinning aerial vehicle that spins about a spin axis, wherein the vehicle rotates about a pitch axis that is orthogonal to the spin axis and is orthogonal to the Earth's gravity axis, and the vehicle also rotates about a yaw axis that is orthogonal to both the spin axis and the pitch axis, the system comprising: (a) an inertial measurement unit (IMU) fixed to the vehicle and comprising: (b) wherein the first gyroscope output signal and the first accelerometer output signal are each modulated by the vehicle spin and thus each possesses an AC component at the vehicle spin rate while the vehicle is spinning; and (c) a phase-sensitive demodulation system that extracts the AC components of the first gyroscope output signal and the first accelerometer output signal, derives a reference signal from the AC component extracted from the first accelerometer output signal, and demodulates the AC component extracted from the first gyroscope output signal using the reference signal, to obtain a DC signal representing the rate of rotation of the vehicle about either the yaw axis or the pitch axis.