The AN/APG-67 is a multi-mode all-digital X band coherent pulse doppler radar originally developed by General Electric for the Northrop F-20 Tigershark program of the early 1980s. It offers a variety of air-to-air, air-to-ground, sea-search and mapping modes, and compatibility with most weapons used by the US Air Force in the 1980s.

When the F-20 project ended in the mid-1980s and no other U.S. sales were immediately forthcoming, GE sold off its radar division. It eventually became part of Lockheed Martin, which sells the APG-67 for use on light fighters and trainer aircraft. It has been selected for the AIDC F-CK-1 Ching-kuo of Taiwan, and the Korean FA-50 fighter variant of the T-50 Golden Eagle.^[1]

Description

The APG-67 is a modern radar featuring a planar phased array antenna and simplified electronics housed in three line-replaceable units, one of these being the radar "dish" itself. The entire system weighs less than 160 pounds (73 kg) and takes up less than 1.9 cubic feet (0.054 m³). All communications with the cockpit is handled using the MIL-STD-1553 data bus; the data bus allows the data from any of the aircraft's sensors to be shown on any of the in-cockpit displays, or sent to other aircraft using a data link.

The system broadcasts an average power of 396 watts, allowing it to detect fighter-sized targets at up to 40 nautical miles (74 km; 46 mi) in tracking modes, and up to 80 nautical miles (150 km; 92 mi) in velocity search. In the air-to-air mode it offers long-range velocity search, track-while-scan with up to ten tracked targets, and a variety of single-target-track and auto-lockon "dogfight" modes. It has a variety of pulse repetition frequencies that are automatically selected depending on whether or not the antenna is looking up or down.^[2]

The APG-67 also includes a variety of air-to-ground modes including real beam ground mapping, synthetic aperture radar imaging (SAR) and beacon tracking.^[2] It can also search for moving targets on the ground and offers tracking modes for ground targets similar to those for air-to-air use. These modes can also be used for sea-surface-search, in which case the display is de-cluttered to remove waves. The SAR mode is an optional add-on to the basic system.^[3]

History

For many years Northrop had worked with Emerson Electric to provide a series of radars for their F-5 series. The original F-5A/B was designed as a light strike aircraft and had only a rudimentary ranging radar for the gunsight, and very little room in the nose for anything else. When the F-5 airframe was adapted into the F-5E/F for the air-to-air role, Emerson designed the AN/APQ-153 to fit into the extremely limited space in the F-5's nose. The small space and severe weight limitations meant that the APQ-153 could offer only the most basic features, including basic single-target-track and a scanning mode with a range about 10 nautical miles (19 km; 12 mi). A further upgrade produced the AN/APQ-159, which offered longer range of about 20 nautical miles (37 km; 23 mi), as well as offering a number of practical improvements like wider scanning angles and improved reliability.

When Northrop started work on the latest member of the F-5 family, then known as the F-5G, Emerson was initially selected to produce a version of the APQ-159 with the capability of firing the AIM-7 Sparrow missile at beyond visual range. However, as the project was repeatedly re-positioned during the late 1970s, Northrop developed the requirement for a much more capable design, able to support both air-to-air and air-to-ground modes like the radars being used in modern designs like the F-16 Fighting Falcon. Emerson's earlier designs were all analog systems so they were not a "shoe in" for the digital system Northrop was looking for, and they threw open the competition to anyone with a suitable design. Several proposals were returned, and General Electric eventually won the contract.^[4]