PROCESSING ASPECTS OF THE SOFTWARE PARIS INTERFEROMETRIC RECEIVER

The use of signals of opportunity, such as those continuously transmitted by the Global Navigation Satellite Systems (GNSS), is a low-cost strategy towards remote sensing purposes. In particular, the analysis of these type of signals reflected off the Earth surface for the retrieval of geophysical parameters is known as GNSS-R. During the last years, many GNSS-R applications have been successfully tested [1], including sea surface characterization, soil moisture sensing, sea ice detection and dry snow layering. In addition, by following the original purpose of the GNSS-R concept presented in 1993 [2], several ocean altimetric experiments have been carried on (e.g. [3]). Moreover, as it was pointed out on this first publication, one of the main advantages of this technique is the possibility of performing mesoscale altimetric measurements by employing the multiple reflection points available over the Earth surface as a result of the extensive GNSS constellation. This point is specially relevant, given that the increase of temporal and spacial resolution that could be then obtained would represent a key feature of the GNSS-R technique to complement RADAR Altimeters. However, to achieve the desirable precision in a spaceborne scenario with several and simultaneous observation areas requires a beamformer strategy to get enough signal power. This is even more significant when considering the interferometric approach of direct cross-correlation between direct and reflected signals, where no encripted codes are needed and higherbandwitdh GNSS signals can be employed. Recently, this type of approach was first proved in an aircraft GNSS-R experiment using high-gain antennas [4]. The next step then, is to prove a beamformer-capable architecture under the same conditions