Design, manufacture and test of a pushbroom radiometer

The principle of the pushbroom satellite radiometer is illustrated. A host of radiometer receivers are connected to an equal number of antenna feeds producing individual beams to sense the Earth simultaneously. Each beam makes the same angle with respect to the direction to the sub-satellite point. Various antenna concepts have been studied to achieve this goal and the optimum solution has been found to be an offset toroidal single reflector antenna where an offset parabola is rotated around the required beam cone axis. In order to validate the feasibility of such an antenna, a pushbroom radiometer demonstration model for aircraft tests has been built on a contract for ESTEC with MATRA, France, as prime contractor. Because of the size of the satellite antenna and the need to fit it onto an aircraft the system is scaled to operate in the 36-37 GHz range, where the antenna has a size in the order of 1 m