AIM Text
- Surveillance radars are divided into two general categories: Airport Surveillance Radar (ASR) and Air Route Surveillance Radar (ARSR).
- ASR is designed to provide relatively short-range coverage in the general vicinity of an airport and to serve as an expeditious means of handling terminal area traffic through observation of precise aircraft locations on a radarscope. The ASR can also be used as an instrument approach aid.
- ARSR is a long-range radar system designed primarily to provide a display of aircraft locations over large areas.
- Surveillance radars scan through 360 degrees of azimuth and present target information on a radar display located in a tower or center. This information is used independently or in conjunction with other navigational aids in the control of air traffic.
Source: FAA Aeronautical Information Manual · current edition · paragraph 4-5-3.
The short answer
This AIM section is FAA advisory guidance describing surveillance radar, split into Airport Surveillance Radar (ASR) for short-range terminal coverage and Air Route Surveillance Radar (ARSR) for long-range coverage. Both scan 360 degrees of azimuth and feed the radar displays controllers use to separate IFR traffic under 14 CFR Part 91.
Research Notes
Common Questions
What is the difference between ASR and ARSR?
ASR provides relatively short-range coverage in the general vicinity of an airport to handle terminal area traffic, while ARSR is a long-range radar system designed primarily to display aircraft locations over large areas.
Can ASR be used for an instrument approach?
Yes. The AIM notes the ASR can also be used as an instrument approach aid, in addition to its primary role of observing precise aircraft locations on a radarscope in the terminal area.
How much azimuth do surveillance radars cover?
Surveillance radars scan through 360 degrees of azimuth and present target information on a radar display located in a tower or center, used independently or with other navigational aids to control air traffic.