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ASR 12

Description of the radar set, tactical-technical characteristics
ATC-Radar ASR 12
(click to enlarge: 308·429px = 14 kByte)

Figure 1: ATC-Radar ASR 12 (© Northrop Grumman)

Specifications
frequency: 2.7 to 2.9 GHz
pulse repetition time (PRT): processor controlled
pulse repetition frequency (PRF):
pulsewidth (τ): 1 µs and 55 µs
receive time:
dead time:
peak power: 22 kW
average power:
instrumented range: 60 / 80 / 100 NM
range resolution: 700 ft
accuracy:
beamwidth: 1.4 degrees
hits per scan:
antenna rotation: 10 / 12 / 15 rpm.
MTBCF: > 37 500 h
MTTR: < 0.25 h

ASR 12

The Northrop Grumman ASR 12 is a modular, fully solid-state S-Band radar system that incorporates the latest technologies in airport surveillance radar systems. It is a further development of the ASR 9 and also uses the same reflector, a curved metal latticework 36 feet wide and 17 feet tall.

Weather conditions detected by the ASR 12 are measured in six levels of intensity conforming to the ICAO standards and are processed using a weather channel processor separate from the aircraft channel.

The operation of the ASR 12 is depicted as a simple “state diagram.” There are two major transitions that occur during each pulse period:

These transitions are adjustable to allow optimization of the radar operation in the clutter conditions of the site.

high beam
low beam
high-beam
receiver
low-beam
receiver
power
divider
transmitter

Figure 2: Radarantenna with high- and low- beam pattern

high-beam receiver low-beam receiver power divider transmitter high-beam circulator low-beam circulator Feedhorn for „low-beam”- Chanel Feedhorn for „high-beam”- Chanel
high beam
low beam

Figure 2: Radarantenna with high- and low- beam pattern

long-range
long-range
short
range
short
range
short
range

Figure 3: Example of radar timeline with different pulse-durations
In the lower elevation the radar radiates a number of „Short-Range-Pulses” in series. This is required for pulse-pair processing practicable in close-up range only.

long-range
long-range
short
range
short
range
short
range

Figure 3: Example of radar timeline with different pulse-durations
In the lower elevation the radar radiates a number of „Short-Range-Pulses” in series. This is required for pulse-pair processing practicable in close-up range only.