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.