Global Navigation Satellite System Reflectometry

Global Navigation Satellite System Reflectometry is passive sensing of the satellites' navigation signals, including all GNSS sources. For this purpose, the GNSS receiver measures the signal delay from the satellite and the rate of change of the range between satellite and observer. The surface area of the reflected GNSS signal also provides the two parameters time delay and frequency change. Since the mid-1990s, researchers have been interested in using data collected through this system to measure the signal delay received. In addition, analyzing these signals provides scientists with new information about the Earth's atmosphere (Rajabi et al. 2020).


Rajabi M, Nahavandchi H, Hoseini M. Evaluation of CYGNSS Observations for Flood Detection and Mapping during Sistan and Baluchestan Torrential Rain in 2020. Water [Internet]. 2020;12(7). Available from:

Related Content


Towards new applications of spaceborne technology on flood protection

Recently, in July 2021, destructive and deadly floods occurred in Western Europe. The estimated insured losses only in Germany could approach 5 billion Euros (AIR Worldwide, 2021). However, the total amount of the damage is currently not foreseeable due to the variety and complexity of the damage patterns and the unbelievable extent of the disaster. It seems the socio-economic losses will dramatically increase and break a new record in the insurance industry after evaluating the complete record of damages’ reports (see Figure 1).