AN/APQ-153 was an I-band, pulse-doppler radar, developed by Emerson Electric for the US Air Force F-5E fighter aircraft. The APQ-153 featured four modes of operation: AA1; AA2 air-to-air target search at different ranges; "Dogfight" which locked onto the closest target and offered ranging and gun cueing; and finally a missile bore-sight cueing mode that calculated the engagement envelope of the AIM-9 Sidewinder and gave the pilot directional cues to help them fly into the envelope.
As a fire control radar, the AN/APQ-153 offered a very powerful way to increase combat capability in the worldwide F-5 E/F Tiger II fleet. Upgrades to the AN/APQ-153 effectively doubled the search range while increasing search volume by eight times. The antenna consisted of a 12 × 16 inch parabolic dish that was stabilized to account for maneuvering. This was connected to a small 5-inch B-Scope display in the cockpit.