All in a Spin about Reticle-Based Seekers

Infrared (IR)-guided (heat-seeking) missiles have been and continue to be extremely widely used in everything from large surface-to-air missiles (SAMs) to tiny shoulder-launched missiles. While many of the reasons for this popularity arise as a result of the underlying physics, the (relative) simplicity and resulting (relatively) low cost of such weapons have contributed significantly to this popularity. Historically, the electro-mechanical reticle-based seekers used in IR seekers have been one of the driving factors behind the simplicity of IR seekers. And while modern IR seekers have largely switched to the use of imaging sensors, reticle-based seekers will remain relevant for the foreseeable future due to stockpiles of older IR-guided weapons, including those in the hands of irregular forces.

The development of reticle-based seekers from simple ideas dating back to the Second World War to advanced-pseudo imaging systems will be explored in this presentation. The main characteristics of each concept, including the reticle pattern and the electro-mechanical modulation of the incoming IR radiation, will be outlined to show how such systems operate.