One of the big drivers for all-weather imaging comes from the aircraft industry. Atmospheric transmission in the millimetre wave band is considerable better in cloud, rain, fog, dust storms and smoke than in the visible and infrared bands, due to the lower level of scattering. This enables capabilities for low-level flying (in mountainous regions), take-off, landing and runway taxiing in conditions of fog, cloud and rain. This also enables a ground surveillance capability from the air through cloud. Uptake of this technology by industry has been slow, because systems have only been demonstrated at TRL 4 to 5. Progression to higher TRL's may be possible using larger collecting area (better spatial resolution and radiometric sensitivity), conformally deployable systems.
Helicopters will be one of the first platforms to take advantage of this capability, as pilots require immediate situational awareness when flying close to the ground in visually degraded environments, such as in low level cloud and fog in temperate climates and dust storms (including brownout) in dry and desert type regions.
A penetrative imaging capability through rain and coastal fog offers a capability for ships to navigate and survey regions close to the shoreline, enabling them to avoid collisions with land and have awareness of approaching water craft. Visible and infrared imagers do not have this capability due to atmospheric scattering and radar systems may not work well due to clutter from the coastline.