Issues concerning the implementation of a low cost attitude solution for an unmanned airborne vehicle (UAV)

The research and development team at Newmont Australia have been working on a UAV, the Tandem Wing, for the purposes of carrying out magnetometer based geophysical surveys. It is imperative for the viability of the project that the cost of constructing and running the UAV are kept to a minimum. In order to eliminate the cost of an expensive INS a multiple antenna GPS array is being used to determine the position, velocity and attitude of the aircraft. The main role of the GPS attitude determination system is to provide an external reliable estimate of the yaw, pitch and roll of the aircraft, which is relayed to the control system. The application of a GPS multiple antenna system is not without its problems, and a number of issues need to be addressed to ensure the successful implementation on the UAV. A good understanding of the system integrity, and how the system will react when loss of lock occurs are both important. This paper will discuss these issues, and attempt to offer solutions.