Warning system concepts to prevent controlled flight into terrain (CFIT)

Terrain Following Radar (TFR) systems have employed techniques for avoiding collision with terrain and man-made obstacles since their inception over twenty years ago. Evolutionary advances in terrain following technology have produced the Covert Penetration System (CPS), which combines information from the forward looking radar with a digital map to enhance the capabilities of the TF component and add functionality such as Terrain Referenced Navigation (TRN), and Terrain and Threat Avoidance (TA/ThA). The addition of the digital map data also enhances the system´s ability to perform the Ground Collision Avoidance (GCA) function. The GCA algorithms used in TFRs and in CPS can be used to help prevent CFlT mishaps. This paper examines the GCA concepts currently employed in Texas Instruments TFRs, their extensions as envisioned for CPS, and concepts for a stand-alone GCA system. Applications to both civil and military aircraft are discussed, as is operation both with and without real-time forward looking sensors