Low-signature Targets Research Articles

Data Analysis of Polyethylene Base RAM for Small Vehicle’s low Signature’s Applications

The signature of radar target is an important aspect in military war. The demands for low signature targets have been increased to achieve the ‘critical mission successes’ in defence. Worldwide scientists and engineers are incessant working on it. This paper presents the data analysis of radar absorbing material (RAM) suitable for attaining of low signature applications for small air vehicles such as sUAV, μUAV, drones, hexcopter, spy birds etc. In this paper, the polyethylene (PE) and their composites characteristics and data analysis are presented, for applications in small air vehicles to attain the lower value of their target signatures. This is achieved in terms of EM measurement parameters of RAM material such as reflection loss, transmission loss, absorption loss, shielding effectiveness (SE), radar cross section (RCS) etc. The obtained values of reflection loss are – 29.49 dB, - 36.91 dB and – 23.94 dB; then, the transmission loss are – 133.18 dB, - 128.70 dB and – 0.19 dB for PE, polyethylene terephthalate (PET) and PET + conductive paint (PETCP) respectively for materials by waveguide measurement (WGM) method. The SE range are – 0.009 dB to – 0.19 dB, - 0.005 dB to - 0.29 dB, and - 0.022 dB to – 1.91 dB in WGM; then, - 9.44E-07 dB to – 1.13E-06 dB, - 9.57E-07 dB to – 1.01 E-06 dB and – 9. 31 E-07 dB to – 1.08E-06 dB in OATS experiments for PE, PET and PETCP respectively for the materials are obtained. The lowest value of RCS in OATS method are 1.63E-08 , 6.46E-08 and 5.63E-08 for PE, PET and PETCP respectively for material are obtained. The contact angle & material thickness (t) are 78.50 & 0.08 mm; 66.18 & 0.09 mm and 93.45 & 0.12 mm for PE, PET and PETCP respectively, are proposed in this paper. There is good agreement between the material controlling parameters design and the tabular analysis presented in this paper. This materials are used as RAM in small aircrafts, sUAV, μUAV, drones, hexcopter, spy birds, ships etc, to attain their low signature value, low RCS, stealth and shielding applications in X – band of 8 to 12 GHz frequency range.

Adaptive Detection of Low-Signature Targets in Forward-Looking GPR Imagery

We present an image-domain adaptive likelihood ratio tests (LRT) detector for low-signature target detection in forward-looking ground-penetrating radar. We exploit multiview tomographic images of the scene under investigation to iteratively adapt the statistics of the targets and clutter arising from the interface roughness. Using numerical electromagnetic data, it is shown that the proposed adaptive LRT detector provides significantly lower false-alarm rates compared with its nonadaptive counterpart while providing comparable detection performance.

Long-range time-of-flight scanning sensor based on high-speed time-correlated single-photon counting

We describe a scanning time-of-flight system which uses the time-correlated single-photon counting technique to produce three-dimensional depth images of distant, noncooperative surfaces when these targets are illuminated by a kHz to MHz repetition rate pulsed laser source. The data for the scene are acquired using a scanning optical system and an individual single-photon detector. Depth images have been successfully acquired with centimeter xyz resolution, in daylight conditions, for low-signature targets in field trials at distances of up to 325 m using an output illumination with an average optical power of less than 50 microW.