| 摘要 |
<p>The invention relates to a device and a method to determine whether a water leakage has occurred in ground by means of Doppler radar. The device comprises a radar emitting unit for emitting electromagnetic waves into the ground, a receiver unit for receiving signals reflected from a fluctuating water surface, a signal processing unit which band pass filters the received signal to obtain a signal that only comprises the Doppler shifted frequencies, creates a measure of the derivative of the reflected signal and, in a decision processor, compares this measure with a threshold value corresponding to the signal value of the background. If the measure of the derivative exceeds said threshold value a leakage is considered to have occurred.</p> |
