| 摘要 |
The invention is a method for detecting oil at the sea by means of a coherent oil spill radar with a transmitter- and a receiver antenna, characterized by the following steps: - the transmitter- and receiver antenna are directed towards a sea surface in the near area out to a given distance of 1000 - 4000 m under a grazing angle of between 0.5 and 30 degrees, - the transmitter antenna transmits at a frequency between 2 GHz and 18 GHz, and frequency modulated with an adjustable bandwidth and with a given transmitted effect less than 10 W, - wherein said transmitter antenna has a horizontal antenna lobe smaller than its vertical antenna lobe, - wherein said transmitter - and receiver antenna are controlled electronically to transmit and detect vertical polarization and horizontal polarization, with an adjustable modulation time of less than 4 ms between the polarizations, - for the received signal for both the vertical and the horizontal polarization the complex signal comprising in-phase and quadrature-phase (I, Q) is normalized wherein the difference in time between the respective polarization measurements are less than a given interval less than 0.5 seconds, by the quotient (Gamma H -Gamma V ) - the calculated quotient is compared with an expected quotient for a clean sea surface, wherein a difference indicates oil on the sea surface, - whereafter the calculated quotients values are fed out on a display unit for showing possible detected oil on the sea surface in the near area of the radar. |
