A Multispectral Camouflage Net Evaluation Capability

The need for standardized guidelines and common evaluation techniques for assessing camouflage nets represents a challenge for the military operational community. This paper proposes a laboratory assessment methodology for the evaluation of camouflage nets. This method aims to be an accurate initial assessment before field tests, as the final stages for camouflage evaluation. Furthermore, it is more convenient to standardize laboratory indoor setups as the initial step because parameters can be controlled with precise equipment, eliminating any unexpected technical variables. Our approach combines radar testing in a semi-anechoic chamber and EO/IR (Electro-Optical/Infra-Red) assessment using an indoor laboratory setup. This method offers a more comprehensive and accurate evaluation compared to methods that focus on a single type of test. Following this procedure, we can assess the performance characteristics of camouflage nets by determining their behavior in all spectral domains associated with surveillance optical and radar equipment. For the EO/IR devices, we are interested in analyzing the nets in the $0.35-2.5\: \mu $ m wavelength band, and both the mid-wave infrared (MWIR) $3-5\: \mu $ m and long-wave infrared (LWIR) $8-12\: \mu $ m thermal infrared transmission bands. For the radar systems, we focus on the X-band frequency in the range of 9 GHz to 11 GHz. The paper presents the results obtained by measuring three different multispectral camouflage net samples. It is shown that Samples Under Test (SUT) have relatively consistent average radar transmission attenuation with a small range of 2.22 dB. Furthermore, the average attenuation values vary between 3.3 dB and 14.71 dB when the camouflage net is rotated for further evaluation. Moreover, radar reflection results characterized by reflection coefficient values, standard deviation, mean, and Coefficient of Variation (CV), show that all samples, regardless of orientation, deviate from the consistent reference data of ten runs. In the thermal infrared domain, the nets are similar in terms of solar loading, showing a similar temperature increase of 8 ± 1° C, but the transmission levels are different, between 11.7% and 21.8%. As for the reflectance measurements, the three SUT show different behaviors in terms of reflectance levels and contrast patterns, especially in the near and shortwave infrared bands of the EO domain.