A method for determining a positioning of a portable device comprising a plurality of sensors (101 - 105) including first one or more sensors and second one or more sensors, each of the sensors in the plurality of sensors (101 - 105) having a confidence, wherein the method comprises: receiving sensor signals from the plurality of sensors (101 - 105), said sensor signals including first sensor signals from the first one or more sensors and second sensor signals from the second one or more sensors; generating positional data including first and second positional data respectively from the first and second sensor signals, said positional data representing positional conditions of the portable device , by modelling the received sensor signals based on predefined models including signal models defining a correspondence between predefined sensor signals and predefined positional data; comparing the first positional data with the second positional data to determine a difference between the first and second positional data; adjusting , for each of the first and second one or more sensors, the confidence of the corresponding sensor by determining a new confidence value depending on a previous confidence value of the sensor (101 - 105) and the determined difference between the first and second positional data; weighting the generated positional data depending on the confidences of the corresponding sensors in the plurality of sensors (101 - 105); and determining the positioning of the portable device based on the weighted generated positional data; wherein adjusting the confidence includes determining whether the difference between the first and second positional data is within a predefined deviation acceptability range, in which case the confidence is kept substantially unvaried. receiving sensor signals from the plurality of sensors (101 - 105), said sensor signals including first sensor signals from the first one or more sensors and second sensor signals from the second one or more sensors; generating positional data including first and second positional data respectively from the first and second sensor signals, said positional data representing positional conditions of the portable device , by modelling the received sensor signals based on predefined models including signal models defining a correspondence between predefined sensor signals and predefined positional data; comparing the first positional data with the second positional data to determine a difference between the first and second positional data; adjusting , for each of the first and second one or more sensors, the confidence of the corresponding sensor by determining a new confidence value depending on a previous confidence value of the sensor (101 - 105) and the determined difference between the first and second positional data; weighting the generated positional data depending on the confidences of the corresponding sensors in the plurality of sensors (101 - 105); and determining the positioning of the portable device based on the weighted generated positional data; wherein adjusting the confidence includes determining whether the difference between the first and second positional data is within a predefined deviation acceptability range, in which case the confidence is kept substantially unvaried. <EOS>