Semi-active radar homing

In addition, the resolution of a radar is strongly related to the physical size of the antenna, and in the small nose cone of a missile there isn't enough room to provide the sort of accuracy needed for guidance.

Additionally, the missile will listen rearward to the launch platform's transmitted signal as a reference, enabling it to avoid some kinds of radar jamming distractions offered by the target.

The closing velocity is used to set the frequency location for the CW receive signal shown at the bottom of the diagram (spectrum).

The missile seeker antenna is a monopulse radar receiver that produces angle error measurements using that fixed position.

In the SARH system the missile listens for the reflected signal at the nose, and is still responsible for providing some sort of "lead" guidance.

The disadvantages of beam riding are twofold: One is that a radar signal is "fan shaped", growing larger, and therefore less accurate, with distance.

This could leave the launch aircraft vulnerable to counterattack, as well as giving the target's electronic warning systems time to detect the attack and engage countermeasures.

Spectral density matched to the receive radar detection bandwidth is the limiting factor for maximum range.

Recent-generation SARH weapons have superior electronic counter-countermeasure (ECCM) capability, but the system still has fundamental limitations.

One difficulty is testing, because this feature creates public safety risks if a fault prevents datalink self-destruct signals when a missile is heading in the wrong direction.

[citation needed] Since Desert Storm, most F-15 Eagle combat victories have been scored with the Sparrow at beyond visual range.