W-band real-time passive millimeter-wave imager for helicopter collision avoidance

A w-band passive millimeter imager is proposed for use on a helicopter platform. The atmospheric transmission through fog and rain is much higher in the millimeter wave band than it is in the visible or infrared regions of the spectrum. This property enables passive millimeter wave imaging systems to offer recognizable imagery in adverse weather conditions. Furthermore, as the technique is based on incoherent imaging, it can be used in environments where it may be difficult for radar to process data into recognizable imagery. The 30 cm diameter real-time passive millimeter wave imager described here will have a radiometric sensitivity of around 1 degree(s)C and a radiation bandwidth of 80 GHz to 105 GHz. The system is based on the DERA mechanical scanning passive millimeter wave imager architecture.