A channel estimation method for chipless wireless sensors is presented. The method is developed to suppress interference signals in radio frequency backscatter systems. It uses two adjacent frequency bands to estimate and suppress the disturbing signal of a dynamic interferer. Afterwards a correction of the sensor tag's backscatter signal is achieved. The method has been tested in indoor measurements with a chipless strain sensor and a chipless temperature sensor. A metal block has been deployed as an interferer. In the given scenario, the method has enabled a determination of the sensors' resonance frequencies with relative errors of <2% in average. A general dependence of the estimation robustness on the peak bandwidth is observed.