Since the late 1950s nav/attack systems have begun to integrate a variety of different sensors, using a computer to compile the data and present it to the aircrew. Although early integrated nav/attack systems suffered from poor reliability, improvements in digital computing technology, particularly the advent of the microchip, have resulted in substantially more sophisticated and effective equipment.
A typical modern nav/attack system is based around an inertial navigation system (INS) that allows the aircrew to locate the target area without reliance on active sensors such as radar that might alert enemies to the aircraft's presence. Since INS is subject to "drift," limiting its accuracy, the nav/attack system periodically updates the aircraft's position based on external radio beacons (such as TACAN) or (since the 1990s) GPS or equivalent satellite navigation system, or using a Doppler radar (although this increases the risk of detection). The system typically provides steering cues to the pilot.
Once the aircraft reaches the target area the nav/attack system assists the crew in calculating range to target and other parameters necessary for the delivery of bombs, missiles, or other ordnance. Modern systems typically provide automatic weapons release: the crew authorizes launch/release (by pressing the weapon trigger or "pickle"), but the nav/attack computer actually releases the weapon in order to insure the correct trajectory and to compensate for wind, aircraft velocity, and other factors.
The goal of modern air forces since the end of World War II has been a system capable of finding the correct target day or night, even in adverse weather. While current nav/attack systems come closer to this goal than the comparatively primitive systems of the 1960s, they still have significant limitations, and remain dependent on intelligence-gathering and pre-mission planning before the aircraft takes off.