Thermal weapon sights with integrated fire control computers: algorithms and experiences

The HuntIR long range thermal weapon sight of AIM is deployed in various out of area missions since 2004as a part of the German Future Infantryman system (IdZ). In 2007 AIM “elded RangIR as upgrade withintegrated laser Range “nder (LRF), digital magnetic compass (DMC) and “re control unit (FCU). RangIR “llsthe capability gaps of day/night “re control for grenade machine guns (GMG) and the enhanced system of theIdZ. Due to proven expertise and proprietary methods in “re control, fast access to military trials for optimisationloops and similar hardware platforms, AIM and the University of the Federal Armed Forces Hamburg (HSU)decided to team for the development of suitable “re control algorithms. The pronounced ballistic trajectoryof the 40mm GMG requires most accurate FCU-solutions speci“cally for air burst ammunition (ABM) andis most sensitive to faint eects like levelling or “ring up/downhill. This weapon was therefore selected tovalidate the quality of the FCU hard- and software under relevant military conditions. For exterior ballistics themodi“ed point mass model according to STANAG 4355 is used. The die rential equations of motions are solvednumerically, the two point boundary value problem is solved iteratively. Computing time varies according to theprecision needed and is typical in the range from 0.1 - 0.5 seconds. RangIR provided outstanding hit accuracyincluding ABM fuze timing in various trials of the Ger man Army and allied partners in 2007 and is now readyfor series production. This paper deals mainly with the fundamentals of the “re control algorithms and showshow to implement them in combination with any DSP-equipped thermal weapon sights (TWS) in a variety oflight supporting weapon systems.Keywords: thermal weapon sight, “re control unit, automatic grenade launcher, “rst hit probability, “re controlalgorithms