基于北斗卫星反射信号的海面溢油探测方法及试验

为了监测小规模固定海域的溢油状况,针对岸基接收平台提出了一种基于北斗卫星反射信号的海面溢油探测方法,该方法将全球导航卫星系统反射信号(GNSS-R)技术应用于岸基条件下的海面溢油探测。进行了岸基试验,利用右旋圆极化(RHCP)天线和左旋圆极化(LHCP)天线分别采集北斗卫星直射与反射信号,在信号同步的基础上提取卫星直射和反射信号的相关功率,并结合北斗卫星的高度角与方位角信息,反演目标海域的介电常数来判断海面有无溢油。试验结果表明探测表面为油面时,介电常数反演结果均值为3.6,标准差为2.13,这与油的真实介电常数范围2.0~4.5一致,远小于海水介电常数,证明将GNSS-R应用到岸基海面溢油探测中具有可行性。

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.