Optical Guidance for Shoreline-Following UAVs

Recent counterinsurgency combat operations in and around inland waters indicate the need for specialized technological capabilities to meet the unique challenges of warfighting in riverine theaters. The ability to conduct close surveillance of enemy activities in the riverine arena is of crucial importance to our warfighters. Over the past several years, the Information Technology Division, in collaboration with the Tactical Electronic Warfare Division, has been developing autonomous unmanned air vehicles (UAVs) capable of guiding their flight course along riverbanks and shorelines. Autonomous UAV guidance based on sensory input rather than GPS promises to increase the flexibility in tasking for single or multiple UAVs. This article describes a guidance and autopilot system that successfully navigated a curved shoreline. The project demonstrated that the near infrared spectrum is particularly good for navigating on shorelines since the land and water are easily distinguishable in these wavelengths, as are objects in the water. Also presented is a new control technique which is able to find control parameters in the image space. This overcomes the need for specialized edge extraction and path generation. Attitude control was maintained by the use of matched long wave infrared thermopiles.