Stealth aircraft

A stealth aircraft is an aircraft which has been designed to absorb and deflect radar (via stealth technology); these are not "invisible" to radar, they are simply harder to detect than conventional technology. In general the goal is to allow a stealth aircraft to execute its attack while still outside the range of the opposing system's detection. Stealth aircraft were most notably used during the Gulf War (1990); although stealth technology has since become less effective, both the United States and Russia continue to develop stealth aircraft.

First-generation stealth aircraft include the F-117 Nighthawk. First-generation planes tend to be composed mostly of flat radar-absorbing surfaces, so as to attenuate the radar signal and reflect radar waves in a direction other than that of the radar transmitter. Second-generation aircraft include the B-2 Spirit and F-22 Raptor. The design of these aircraft benefited from sophisticated computer modeling of radar response that allowed them to incorporate curved surfaces, which are more aerodynamic than the flat surfaces on first-generation stealth aircraft.

A number of methodologies to detect stealth aircraft at long range have been developed. Both Australia and Russia have announced that they have developled processing techniques that allow them to detect the turbulence of aircraft at reasonably long ranges (possibly negating the stealth technology). The UK has announced a system that uses the signals broadcast from the huge number of cellular telephone towers to generate a synthetic picture, although it is not clear if this method is actually practical. A general feature of these systems is that they use a large number of low-accuracy radar systems (or signal sources) combined with heavy computer processing to generate tracking information. For this reason they tend to be useful only in the early warning role, and have limited applicability to guidance radars for missile systems, and are rarely portable. The problem of successfully countering stealth aircraft on the battlefield remains essentially unsolved.