Sea surface oil spill detection method using BeiDou satellite reflected signal and its experiment

To monitor the oil spill situation in small-scale fixed sea area, a shore-based sea surface oil spill detecting method was developed using BeiDou reflected signal. This method applies/global navigation satellite system-reflection (GNSS-R) technology to shore-based oil spill detection. A shore-based experiment has been carried out, in which a right hand circular polarization (RHCP) antenna and a left hand circular polarization (LHCP) antenna were used to gain the direct and reflected raw signal power from the BeiDou satellites based on signal synchronization respectively. After BeiDou satellites' elevation angle and azimuth angle are taken into account, whether oil spill events happened or not can be judged from the retrieved dielectric constant of sea surface, which is obtained from the reflectivity calculated according to the extracted signal power values. Experiment results show that the mean and standard deviation of retrieved dielectric constant is 3.6 and 2.13 respectively on an oil covered surface, which is in accordance with real oil dielectric constant that falls between 2.0 and 4.5, and much smaller than dielectric constant of sea water. It proves that the method using BeiDou reflected signal is feasible to detect oil spill events in shore-based environment.