Apparatus and method for calibrating a radio positioning based position finding device

Described is an apparatus for calibrating a position finding device, having a comparer for comparing a received radio signal pattern to a multitude of reference radio signal patterns, a determiner for determining a signal strength difference, and a determiner for determining a calibration value. The comparer for comparing is configured to select a selection subset from the multitude of reference radio signal patterns by means of a measure of matching between the received radio signal pattern and one reference radio signal pattern, respectively. Determination of the calibration value is based on the signal strength difference, and the determiner for determining the calibration value is further configured to provide the calibration value to the position finding device. Also described are a position finding device for radio-based localization, having such an apparatus for calibrating, a method of calibrating a position finding device based on radio-based localization, and a computer program for performing the method are described.