air surveillance radar
Also found in: Acronyms.
air surveillance radar[¦er sər¦vā·ləns ¦ra‚där]
Radar of moderate range providing position of aircraft by azimuth and range data without elevation data; used for air-traffic control.
air surveillance radar (ASR)
A radar deployed around the aerodromes that can detect aircraft within 360° and at a range of 60 NM. The radar does not have the resolving power of precision approach radar (PAR) but has a higher range and 360° coverage. The radar can be used for a ground-controlled approach to a limited extent. Since no control of altitude is available and the accuracy of lateral control is less than that of PAR, the airplane must break through any overcast at a higher altitude than in a PAR. The ASR can be used to bring aircraft within one mile of touchdown.