Precise Attitude Measurement

This effort will develop a precision attitude sensing system for use on moving vehicles. Our approach will use an Inertial Measurement Unit (IMU) and GPS antennas mounted fore and aft on the vehicle. The traditional IMU/GPS velocity matching solution offers precise pitch/roll attitude estimation but suffers from poor observability of the yaw angle estimate. The GPS interferometry approach to attitude measurement requires three or four antennas with large separation along two orthogonal directions to achieve precision-leading to installation complexity and platform flexibility concerns. The proposed solution combines feature of both approaches to allow sub-mrad attitude accuracy and high measurement bandwidth under all vehicle operational conditions. Because multiple attitude solutions are integrated, only two GPS antennas are required. This effort will include simulation analysis to address achievable accuracy and to show sensitivities to key design parameters. A limited group test will be conducted using an available IMU and commercial GPS receivers. A detailed point design will be prepared describing a prototype system suitable for demonstrating the method on an airborne platform.