Guide · 2 min read
Missile guidance
Guidance is what separates a missile from an unguided rocket. This guide complements the missile families chapter with a conceptual overview of guidance methods.
Command guidance and SACLOS
In command guidance, steering corrections are computed outside the missile and transmitted to it. Early anti-tank missiles used manual command guidance, with the operator steering the missile. Semi-automatic command to line of sight (SACLOS) automated this: the operator keeps the sight on the target and the launcher tracks the missile and sends corrections, over wire on the TOW-2B or a laser link on others such as the Kornet.
Beam riding
A beam-riding missile flies inside a laser or radar beam pointed at the target, with sensors at its rear keeping it centred. The launcher must keep the beam on target until impact.
Infrared and imaging infrared
Infrared seekers home on the heat a target emits. Early seekers tracked a single hot point; modern imaging infrared (IIR) seekers form a thermal picture of the scene, improving discrimination. Examples include the AIM-9 Sidewinder, the Stinger MANPADS and the IIR-guided Javelin.
Semi-active and active radar
A semi-active radar seeker homes on radar energy reflected from the target, which another radar illuminates. An active radar seeker carries its own transmitter, so the launching platform can stop guiding it once the seeker acquires the target, as on the AIM-120 AMRAAM. Many surface-to-air missiles such as the Patriot PAC-3 combine methods across flight phases.
Inertial and satellite navigation
An inertial navigation system (INS) measures accelerations to estimate position without external signals; it drifts over time. Satellite navigation (GNSS) corrects that drift. Combined GNSS/INS is common on cruise missiles such as the Tomahawk, often with terminal seekers for the final phase. Accuracy is often summarised as circular error probable (CEP).
Fire-and-forget
Fire-and-forget describes any system that needs no further input from the operator after launch, because the missile's own seeker or navigation guides it. It is a property of a system, not a separate guidance technology.
FAQ
- What does SACLOS mean?
- Semi-automatic command to line of sight: the operator keeps the sight on the target while the system automatically steers the missile onto that line.
- What is the difference between semi-active and active radar homing?
- Semi-active seekers home on reflections from an external illuminator; active seekers carry their own radar transmitter.
- Is fire-and-forget a guidance type?
- No. It describes a system that needs no operator input after launch, achieved with an onboard seeker or navigation.
Educational and historical overview based on public sources. See data sources and methodology.