Terrain-following radar
Overview
 
Terrain-following radar (TFR) is an aerospace
Aerospace
Aerospace comprises the atmosphere of Earth and surrounding space. Typically the term is used to refer to the industry that researches, designs, manufactures, operates, and maintains vehicles moving through air and space...

 technology that allows a very-low-flying aircraft
Aircraft
An aircraft is a vehicle that is able to fly by gaining support from the air, or, in general, the atmosphere of a planet. An aircraft counters the force of gravity by using either static lift or by using the dynamic lift of an airfoil, or in a few cases the downward thrust from jet engines.Although...

 to automatically maintain a relatively constant altitude above ground level. It is sometimes referred-to as ground hugging or terrain hugging flight. The term nap-of-the-earth
Nap-of-the-earth
Nap-of-the-earth is a type of very low-altitude flight course used by military aircraft to avoid enemy detection and attack in a high-threat environment....

flight may also apply but is more commonly used in relation to low-flying military helicopters, which typically do not use terrain-following radar.
 
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