Patent ID: 8872696

Claim:
A method of determining a filling level of a product contained in a tank, the method comprising the steps of: a) in a probing state, transmitting an electromagnetic probing signal towards a target area of a surface of said product; b) receiving a reflected probing signal being a reflection of the electromagnetic probing signal at said surface; c) determining a parameter value indicative of an amplitude of the reflected probing signal; returning to step a) if said parameter value determined in step c) is indicative of an amplitude smaller than or equal to said predetermined threshold value; and if said parameter value determined in step c) is indicative of an amplitude larger than a predetermined threshold value, the method further comprising steps of: d) in a measuring state, transmitting an electromagnetic measuring signal towards said target area of the surface; e) receiving a return signal being a reflection of the electromagnetic measuring signal at the surface; and f) determining the filling level based on a time relation between said electromagnetic measuring signal and said return signal; wherein said probing signal is significantly shorter than said measuring signal.