Beyond visual range

With respect to air-to-air missiles, a beyond visual range (BVR) missile is one intended to be fired at targets that the pilot has not visually identified. The decision to fire may be from the crew of the launching aircraft, or an airborne or ground-based intercept control officer.

Such missiles may use several kinds of guidance. The first requisite for guiding to the general area of the target depends on whether the missile can be given the actual location of the target, and updated as it approaches the target. In such a case, it could use semi-active radar homing (SARH) or command guidance to get near the target, constantly adjusting its flight path to maximize the chance of collision. It still would be likely to switch to a terminal guidance mode, using active radar, SARH, or infrared, when it nears the target.

If the go onto target paradigm does not work, the midcourse guidance will have to help the missile go onto a location in space, in which it flies to the general area of the target, and then goes into an autonomous search mode, probably with active radar, which will locate the target. The missile might or might not depend on that active radar for terminal guidance, or might supplement the radar with infrared for its final approach.

Early BVR missiles, like the AIM-7 Sparrow, were almost always SARH. Unless the transmitter for SARH was on other than the launching aircraft, there was an undesirable tactical requirement for that aircraft to continue in the direction of the target, to keep it illuminated with its own radar.

Longer-range missiles like the obsolete AIM-54 Phoenix, Vympel R-33 /NATO: AA-9 AMOS or the current AIM-120 AMRAAM, use active radar, possibly supplemented with inertial or GPS guidance to get to a location where they turn on active radar. In the latter case, the target is likely to become aware of the missile only when it is in final acquisition, perhaps too late to evade it.