The first electronic improvements came with the expansion of the B-52's mission to low-level penetration and the need to fly at an altitude of 500 feet or less. A key element of this modification was the Advanced Capability Radar (ACR) for terrain avoidance that was added beginning in the early 1960s. In the early through mid-1970s, the G and H models received the Electrooptical Viewing System (EVS) that consisted of Low Light TV (LLTV) and Forward-Looking Infrared Radar (FLIR) that, when used with the ACR, meant much safer and effective low-level capability.
A Stability Augmentation System was added in the G and H models in the early 1970s to improve level flight characteristics, reduce structural loads, and improve controllability in turbulence. Other electronic improvements have included many upgrades to Electronic Countermeasure (ECM) and Defensive Avionics systems. The ability to communicate with the AFSATCOM communications satellite was added starting in the late 1970s. In the early 1980s, a Trail Warning System was added on the B-52G and H to provide radar warning of threat aircraft and missiles as well as automatically triggering chaff and flare dispensing to confuse enemy radar.
In 1980, a 10-year $1.5 billion program was begun to replace the analog computer-based bomb navigation system with a modern digital, solid-state Offensive Avionics System (OAS) on the G and H models. The OAS not only reduces life cycle costs, but offers greatly improved performance while maintaining compatibility with other systems on the B-52. A similar though less ambitious improvement was also carried out on the D models.