Fata Morgana

Today, overwater emitter localization is performed using a combination of direction finding and/or multilateration. Both techniques inherently require multiple, well-separated receivers determine 3D emitter locations. The lensing effects of atmospheric ducting and surface reflections can potentially produce near-field phenomena whereby the electric fields received from an emitter is sensitive to the range to that emitter as well as the azimuth and elevation angles. The purposes of this Phase 1 proposal are (1) quantify the 3D location accuracies that may be possible in various propagation environments, including variable sea surfaces, a variety of weather, sea-states, and ducting conditions, various transmitter and receiver positions and for different configurations of receiver array element geometries and (2) make recommendations for a Phase II data collection architecture and overwater testing campaign with the potential of demonstrating the effectiveness of this approach.