Patent ID: 8275509
Filing Date: 2012-09-25
Classification: G01P,G07C

Abstract:
1. A method of operating a tachograph system comprising a plurality of sensors and a computation unit configured to detect and store at least a speed as a piece of registration-relevant information for the tachograph system, the method comprising: detecting a signal from each of the plural sensors for determining the speed; checking the detected signals for plausibility by comparing the detected signals; storing a sensor-related error message if the detected signals differ more than a predetermined amount; checking one of the plural sensors that is a pilot sensor and has an associated pilot function for plausibility using the detected signals from the other plural sensors; flagging the pilot sensor as erroneous when the signals supplied by the other plural sensors differ from one another within a preset limit and a signal from the pilot sensor differs beyond the preset limit; ascertaining the speed based on the plausibility-checked signals from a majority of the plural sensors when the pilot signal is flagged as erroneous, wherein the signals from the majority of the plural sensors differ from each other within a preset limit; and storing an error message when the pilot signal is flagged as erroneous.