The APG-77 was highly appreciated by pilots transitioning from F-15s upon the F-22's introduction in 2005, providing a massive boost in situational awareness. The APG-77 has an incredibly fast scan time across its 120 degree field of view and could detect aircraft from over 320 mi (515 km) away. The AN/APG-77 system itself exhibits a very low radar cross-section, supporting the F-22's stealthy design.[3] The upgraded APG-77(V)1 may have an even greater range. Much of the technology developed for the APG-77 was used in the AN/APG-81 radar for the F-35 Lightning II, and in turn the technology from the APG-81 was applied to the upgraded APG-77(V)1.
The APG-77(V)1 was installed on F-22 Raptors from Lot 5 and on.[4] This provided improved air-to-air performance, full air-to-ground functionality (high-resolution synthetic aperture radar mapping, ground moving target indication and track (GMTI/GMTT), automatic cueing and recognition, combat identification, and many other advanced features).[5][4][6]
^Hoffman, Carl (November 2005). "The Raptor Arrives". Air and Space Magazine. Archived from the original on January 22, 2022. Retrieved December 3, 2023.