for terrain-avoidance

Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified > Radar or analogous systems, specially adapted for specific applications > for anti-collision purposes > of aircraft or spacecraft > for terrain-avoidance

Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified > Radar or analogous systems specially adapted for specific applications (electromagnetic prospecting or detecting of objects, e.g. near-field detection, G01V3/00) > for anti-collision purposes > of aircraft or spacecraft > for terrain-avoidance