EW Academy · Contents · Chapter 9 · §9.3 · Nederlandse versie

§9.3 Phases of the missile intercept

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An intercept runs in three phases, each with its own guidance needs:

  1. Boost / launch phase: the motor burns, the missile accelerates and climbs away from the platform. Often no fine guidance yet: the missile flies a safe, pre-programmed profile until the seeker or the datalink takes over.
  2. Midcourse phase: the long middle section. The missile flies energy-efficiently to a predicted intercept point, steered by inertial navigation with datalink updates from the fire control system ("the target is now over here"). For long-range missiles this is by far the longest phase.
  3. Terminal phase: the end game. The missile's own seeker acquires the target ("acquisition" or "lock-on") and steers the missile with high precision to impact or the detonation point. This is where seeker performance, target manoeuvres and countermeasures count.
launch target boost midcourse (INS + datalink) terminal (seeker)
The three phases of an intercept; many missiles switch guidance method from phase to phase.

Modern missiles therefore combine guidance methods per phase — for example: inertial + datalink (midcourse) and an active radar seeker (terminal). For the target, every phase transition means a change in threat and in warning: the switch to active terminal homing is heard on the RWR as a new, approaching emitter ("pitbull").