Passive ranging using an infrared search and track sensor

We present new techniques for passive ranging with a dual-band IR search and track (IRST) sensor aboard a ship. Three distance estimation methods are described: the atmospheric propagation model, the apparent surface of the target, and target motion analysis (TMA). These methods are tested on the sensor output of real data during cold water trials (CWTs). They are evaluated by comparing with simultaneously obtained radar reference data at the test site. Results of these three passive ranging and three fusion processes, combining the preceding methods, are presented. This demonstrates the effectiveness of IR passive ranging techniques in the anti-air-warfare scenario. Majority voting fusion shows that improvement of the distance estimation is achieved in the CWT scenario when combining these three different methods. A range-error reduction of 41% is obtained, and a typical uncertainty of 5% is at a 8-km distance. During warm water trials (WWTs) the TMA algorithm was adapted to deal with a dynamic environment of the antisurface warfare scenario (ASuW). These WWTs prove that TMA in combination with an IRST system can extend the basic IRST functionality significantly for a dynamic ASuW scenario. © 2006 Society of Photo-Optical Instrumentation Engineers