Method for registering a fill level in a collecting tank by means of a sensor system, wherein the collecting tank comprises m registration regions that are to be measured by means of ultrasound, comprising the following steps: 1.0 an initialization is performed for a certain type of collecting tank that is to be measured, wherein, in the initialization a previously established profile for this type of collecting tank is provided out of a data storage module, wherein the profile depends on the particular type of collecting tank as well as on its tank dimensions and in the profile limit values for the fill level of the type of collecting tank are defined as well as boundary conditions with respect to atmospheric humidity or temperature are included and wherein as the lower limit value the minimum fill level and as the upper limit value the maximum fill level of the collecting tank are defined, 1.1 for each of the m registration regions a measuring cycle (12 to 14) is performed, wherein m = 2, 3,...., 1.2 in each measuring cycle (12 to 14) n individual measurements are performed with n = 2, 3,..., wherein during each of the n individual measurements a transmitting power and/or a receiving amplification and/or a transmit burst is adapted whereby the individual measurements differ from one another by their transmitting power and/or receiving amplification and/or transmit burst, wherein with each individual measurement an ultrasonic transducer of the sensor system outputs a signal that is reflected as an echo signal by a content of the collecting tank and/or by a bottom of the collecting tank and that the echo signal is converted by the ultrasonic transducer into an electric signal that is transmitted from the ultrasonic transducer to a control module, 1.3 for each measuring cycle (12 to 14) a plausibility check is performed by the control module, wherein by means of the plausibility check the usable measurement values out of the n individual measurements of each measuring cycle(12 to 14) received are further processed and invalid measurement values are rejected. 1.0 an initialization is performed for a certain type of collecting tank that is to be measured, wherein, in the initialization a previously established profile for this type of collecting tank is provided out of a data storage module, wherein the profile depends on the particular type of collecting tank as well as on its tank dimensions and in the profile limit values for the fill level of the type of collecting tank are defined as well as boundary conditions with respect to atmospheric humidity or temperature are included and wherein as the lower limit value the minimum fill level and as the upper limit value the maximum fill level of the collecting tank are defined, 1.1 for each of the m registration regions a measuring cycle (12 to 14) is performed, wherein m = 2, 3,...., 1.2 in each measuring cycle (12 to 14) n individual measurements are performed with n = 2, 3,..., wherein during each of the n individual measurements a transmitting power and/or a receiving amplification and/or a transmit burst is adapted whereby the individual measurements differ from one another by their transmitting power and/or receiving amplification and/or transmit burst, wherein with each individual measurement an ultrasonic transducer of the sensor system outputs a signal that is reflected as an echo signal by a content of the collecting tank and/or by a bottom of the collecting tank and that the echo signal is converted by the ultrasonic transducer into an electric signal that is transmitted from the ultrasonic transducer to a control module, 1.3 for each measuring cycle (12 to 14) a plausibility check is performed by the control module, wherein by means of the plausibility check the usable measurement values out of the n individual measurements of each measuring cycle(12 to 14) received are further processed and invalid measurement values are rejected.