Design Aspects Of The Advanced Microwave Sounding Unit (amsu-b~

The AMSU-B is a 5 channel microwave radiometer which is being developed in parallel with the AMSU-A; a 15 channcl microwave radiometer. While both are complete self calibrating radiometers, AMSU-B will be flown with an AMSU-A to provide a 20 channel microwave radiometer called t he Advanced Microwave Sounding Unit AMSU. The overall purpose of the AMSU is to receive and measure radiation from a number of different layers within the atmosphere in order to obtain global data on temperature and humidity profiles. The frequencies of operation of AMSU-B are centred on 89, 150 and 183.31GHz. Key aspects of the AMSU-B instrument addressed by this paper are the design of the antenna, scanning mechanism and electronic c ontrol system required to meet mission requirements including high beam efficiency (>95%) and precise beam pointing accuracy, * 0.1.