Patent ID: 9217787
Filing Date: 2015-12-22
Classification: G01S

Abstract:
1. An apparatus for calibrating a position finding device, comprising: a comparer configured to compare a received radio signal pattern to a multitude of reference radio signal patterns, the comparer being configured to select a selection subset from the multitude of reference radio signal patterns according to a measure of matching between the received radio signal pattern and one reference radio signal pattern, respectively, from the multitude of reference radio signal patterns; a determiner configured to determine a signal strength difference pattern between the received radio signal pattern and the reference radio signal pattern, respectively, of the selection subset; and a determiner configured to determine a calibration value based on the signal strength difference pattern and to provide the calibration value to the position finding device to use the calibration value to accordingly correct signal strengths determined by the position finding device, the received radio signal pattern comprises at least one of transmitter IDs of receivable radio transmitters and signal strengths of received radio signals, wherein the comparer is further configured to relate relative signal strengths for different ones of the transmitter IDs within the received radio signal pattern to corresponding relative signal strengths within the respective one of the multitude of reference radio signal patterns and to infer the measure of matching therefrom; and wherein the comparer is configured to select the reference radio signal patterns for the selection subset which meets the following criteria related to an accuracy (ACC) of measure-of-matching values: wherein ACC