Passive Terrain Following

"Helicopters of the United States Special Operations Command perform missions that require flight at extremely low altitudes and high speeds in order to avoid detection. Currently MH-60K and MH-47E aircraft use a multi mode radar (MMR) to navigate andavoid ground hazards. Such active systems are detectable by passive observers. Helicopters can avoid the use of active systems through the use of Passive Terrain Following/Terrain Avoidance (Passive TF/TA). This technique also has the potential to lowerthe overall altitude of such flights and give the pilots considerable situational awareness. The technology now exists to develop such systems.ALPHATECH proposes to develop and demonstrate algorithms for Passive Terrain Following/Terrain Avoidance. The algorithms will be specifically designed to handle the problems of bias and error peculiar to terrain estimation, and will be based onmultiresolution statistical models. This approach has several advantages including the versatility to accept data of varying resolutions and irregular sampling geometries, as well as the algorithmic speed, that is linear in the number of grid points.Using this approach, ALPHATECH will evaluate the performance of Passive TF/TA under data of varying resolutions. This study will help determine the data and hardware requirements for an operational Passive TF/TA system. The proposed technology willprovide the army with a passive solution for Terrain Followin