GAS

Omnisys Instruments has developed, together with RUAG Aerospace Sweden AB, a system which demonstrate an innovative instrument concept for future atmospheric microwave sounding. In terms of performance, the specification is: 30 km resolution over the earth disc (400x400 map), covering the frequency bands 53, 118, 166, 183, 340, 380 GHz, and an update rate of 30 minutes. Due to the large aperture size required to achieve 30 km horizontal resolution from GEO, its use has so far been restricted to the case of LEO satellites. This will now be accomplished with a synthesised aperture using over 500 (sub) millimeter receivers mounted on a Y-shaped 8 meter boom structure.

Omnisys has performed an ESA financed demonstrator study on the instrument. The demonstrator consist of 20 dually polarised 50 GHz receiver front-end units with multi-functional single-chip receiver MMIC. These front-end units are mounted in a sparse array on a rotating mechanical structure. The instrument concept is 900 mm in diameter.

The central processing core of the demonstrator performs IF conditioning, quantisation and cross correlation of all combinations of the 40 (2x20) down converted signals. Adding to this are the phased locked local oscillator with distribution, power conditioning and distribution unit and electronics control unit.