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• COUNTRY OF ORIGIN: USA
• DESIGNATOR: AWG-9

DESCRIPTION

The AN/AWG-9 is an aircraft weapon control system that can simultaneously track up to 24 targets and guide missiles to 6 of them. Developed to control the AIM-54 Phoenix air-to-air missile, the AWG-9 can be used with AIM-7 Sparrow, AIM-9 Sidewinder, and AIM-120 AMRAAM missiles, as well as for the F-14's M61 20-mm Gatling gun. Its transmitter can generate Continuous Wave, pulse, and pulse-Doppler beams.

The AWG-9 radar can detect targets as low as 50 ft (15 m) and as high as 80,000 ft (24,384 m) at ranges over 115 nm (132 mi; 213 km), and across a front more than 150 nm (173 mi; 278 km) wide.

The system has 26 powered units including 3 units for the digital general-purpose computer, 2 power supply units, 4 radar units, the antenna, 5 signal processors, 3 transmitter power units, 3 missile auxiliary units, and 5 elements for the cockpit display.

The slotted, planar array antenna has a 36-in (914-mm) diameter and has 2 rows of 6 dipole arrays for the Identification Friend or Foe (IFF) system. It is raster-scanned in "bars". The search area is subdivided into horizontal slices, the number of slices describing the particular pattern (e.g., a 4-bar pattern numbered 1 to 4 from bottom to top may scan in a 4-2-3-1 order). A broad sweep will take 13 seconds and divide a large 170-deg wide volume into 8 bars; the tightest pattern is a 1/4-second, 1-bar sweep over 10 deg. The AWG-9 can also scan in 2- and 4-bar patterns; intermediate azimuth limits are 20 and 40 deg.

2 Travelling Wave Tube transmitters energize the antenna. 1 is used for Continuous-Wave (CW) illumination of a target for the Sparrow's Semi-Active Radar (SAR) homing seeker. The other TWT provides either conventional pulse or pulse doppler beams and can operate in 1 of several modes. Pulse modes include search (PS) and single-target-track (PSTT). Pulse-Doppler modes include:

• Search (PDS) for range rate and bearing
• Range-While-Scan (RWS) using a high Pulse Repetition Frequency (PRF) that generates a range as well as range rate and bearing
• Single-target-track (PDSTT) for velocity measurement and jam-angle tracking
• Track-While-Scan (TWS) for Phoenix missile targeting of up to 24 targets simultaneously within a 2-bar, 40-deg or 4-bar, 20-deg pattern, which yields a 2-sec scan rate. Time-sharing techniques permit simultaneous mid-course guidance of 6 Phoenixes at once against 6 different targets.

Other modes include a Vertical Scan Lock-on (VSL) in which the radar scans a 40-deg vertical plane with a 4.8-deg-wide beam.

The "slice" has a lower threshold between 15 deg below the aircraft axis (ending at 25 deg above) and 15 deg above (ending at 55 deg above). Pilot-Rapid-Location (PRL) is effectively a boresight mode using a 2.3-deg-wide beam. Both conventional and pulse-Doppler modes can be slaved to an Infrared Search and Tracking (IRST) system in which the IRST passively acquires a target and the radar illuminates the target at the appropriate time.

STATUS

Production of complete AWG-9 systems ended in August 1988; spares manufacture ended in 1989. Manufactured by Hughes Aircraft Company Radar Systems Group, El Segundo, Calif

PLATFORMS/USERS

F-14 Tomcat

VARIANTS

AWG-9
Production version.

APG-71
Upgraded digital version that improves or replaces every element of the AWG-9 except for the transmitter, power supply, and aft cockpit display; see separate database entry.

ISSUES

Although the AWG-9 has an impressive potential for fleet defense, it is worth noting that the Phoenix has never been used in combat and the Sparrow's success rate against hostile targets in the 1980s (4 Libyan and 1 Iranian aircraft) is 1 out of 6. 3 of the 4 Libyan aircraft shot down were hit by IR-guided Sidewinders at close range.

Information from the US Navy