The main goal of GEROS-ISS is to demonstrate the capabilities of GNSS remote sensing to derive geophysical parameters of ocean, ice and land surfaces, which are associated with geophysical research with special focus on relevant climate change phenomena.
To reach the mission objectives GEROS-ISS payload must be capable of receiving multiple GNSS direct and reflected signals coming from different directions within a wide angular range. In addition, the signals have to be received with a sufficiently high antenna gain so as to guarantee range performance, crucial for the first priority mission objective, altimetry. The type of antenna which can fulfil all these requirements is a beamforming antenna. Such an antenna consists of a number of elements whose output signals are split, phase shifted and combined to form multiple and simultaneous high gain beams pointing towards the desired directions.