This paper describes a novel method for enhancing the infrared signature of surrogate or decoy armored vehicles. The method consists of using water tanks of a calculated thickness to emulate the heat capacity of thick metal on armored ground vehicles. Extensive experiments have shown that the surface temperature of the water tanks closely matches the surface temperature of thick metal plates over an entire diurnal cycle. Passive infrared signatures are duplicated since the surrogate vehicle component has the same innate thermal characteristics of the vehicle component to be emulated. Multiple fidelity, cost, and labor saving advantages are included by using water tanks. Infrared signature fidelity is enhanced since the water tank will have the correct surface temperature irregardless of location, time of day, time of year, or weather conditions. No external heat inputs are necessary to constantly adjust the water tank's temperature. The tanks can be made from any thickness of metal which greatly reduces the cost of materials and labor to construct a surrogate or decoy vehicle. This paper presents the derivation of the design equations for the water tanks as well as extensive experimental results under a variety of environmental conditions. In addition, results are presented for a similar concept where the equivalent heat capacity concept is used to replace solid aluminum with thinner plates of solid steel.
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