OVERVIEW: Terrain-Following Radars (TFR) enable aircraft to maintain low-altitude flight by automatically adjusting altitude to follow the contours of the terrain. These systems are crucial for penetration missions, especially for strike aircraft and bombers aiming to avoid radar detection.

GENERAL DESCRIPTION: TFRs are specialized radars that continuously scan the terrain ahead of an aircraft, generating a real-time profile of the ground surface. The radar computes safe flight paths and interfaces with the aircraft's autopilot to maintain a constant altitude above ground level. Typical TFRs operate in the Ku-band or X-band and are optimized for precision and rapid response rather than long-range detection. They may incorporate Doppler filtering, digital terrain models (DTM), and clutter rejection to enhance performance in complex terrain and adverse weather. TFRs were commonly found on Cold War-era strike aircraft and continue to be used in some modern platforms for nap-of-the-earth flight profiles.

ROLE SUMMARY:
Category: Terrain-Following / Navigation Radar
Primary Use: Automatic low-altitude navigation
Function: Active radar with autopilot guidance interface
Platform: Tactical aircraft, bombers, UAVs
Integration: Tied to autopilot, INS/GPS, and threat-avoidance systems

See Specific information under [Sensors/EW] and [Properties] sections.

SOURCE:
Raytheon and Westinghouse Radar Systems Documentation
https://en.wikipedia.org/wiki/Terrain-following_radar
Janes Avionics Systems