Mistrale will develop a prototype of a GNSS Reflectometry sensor integrated on a dedicated RPAS platform. The GNSS-R sensor will measure (and store) the direct GNSS signals as well as the indirect signals reflected on the ground. The difference between the direct and reflected signals are a good measure of the soil moisture properties. The data will be used to compute soil moisture maps. In this project the technology will be optimised and will be made ready for roll-out.
The GNSS-R concept is comparable to radar technology. It uses the available GNSS signals which are in the L-Band which has been proven suitable for soil moisture retrieval. The use of GALILEO signals, with its larger bandwidth and its different carriers, on top of GPS and GLONASS, will enable better accuracy of GNSS-R measurements.
Flooded areas can also be detected by measuring 100 percent water saturation content, even with a vegetable cover (bushes, grass, trees). In comparison, X or C band radars (most of them are on satellites) cannot deal with vegetation. Satellite embedded L band radars could perform measurements throw vegetation but they provide 30-45 day time period. This is obviously inacceptable for our targeted applications. Others airborne L band radar are heavy and expensive, not suitable for RPAS use. Thus, GNSS-R is a highly valuable technique to monitor the flooded areas. In addition, combined with meteorological forecast, it provides a very useful support to the risk management of the flood-prone areas.