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

Unmanned Airborne Vehicles (UAVs) today are designed for specific applications in mind, with the majority of UAV applications being focussed on reconnaissance-type missions, reflecting the large military interest in the platform. While a UAV usually is much cheaper than a military attack or surveillance aircraft, the cost of constructing, running and maintaining a UAV is often beyond what civilian operators can afford. A significant portion of the cost of the UAV is made up by the navigation system used to control the aircraft. Traditionally many of the UAVs in military applications have to assume that GPS may be jammed, and so a philosophy of using GPS for navigation, but to not completely rely on its availability has become entrenched. This has often then required an expensive high quality INS system to be installed on the UAV, thus significantly increasing the cost of the UAV. Fortunately for civilian operators there is no need to assume there will be an enemy jamming GPS, and the reliance upon an expensive INS may be ignored. In this paper we look at the issues of implementing a low-cost single-frequency GPS antenna array for attitude determination to be used to help control a UAV. The paper will include findings on the integrity and quality control of the solution, recovery of signal after loss-of-lock, and the benefits of the integration of low-cost angular rate gyros into the navigation solution.