Moving toward commercialisation of chipless radio-frequency identification (RFID) systems, there is a significant challenge for the detection of chipless tag in a practical application, in which the conventional calibration techniques such as background subtraction are insufficient or even impractical. In this study, first, a processing algorithm for an inverse problem based on the range estimation is introduced. In an inverse problem, the tag ID and its distance to the reader are unknown. Employing the proposed algorithm, provided the specification of the reader antenna is known, the desired component of the received signal corresponding to the tag ID can be extracted without the requirement of background calibration. Then, a post-processing algorithm is proposed for the extraction of the tag ID, which provides a sustained detection outcome at an arbitrary distance. The proposed algorithms are verified with the help of a few datasets acquired from the simulation environment as well as measurement setups. A typical backscattering chipless RFID tag with six resonances is examined. The distance between the tag and the reader antenna is estimated, and the binary tag ID extracted successfully.