A method of localising a vehicle hosting a sensor comprising the steps of: a) capturing data from the sensor providing a sensed scene around the vehicle at a current time; b) processing the sensed scene to extract a set of features from the sensed scene and to estimate, using the extracted features, a position of the vehicle; wherein the estimation is performed by: c) comparing the extracted set of features from the sensed scene to a plurality of stored experiences to ascertain whether the sensed scene can be recognised within any of the stored experiences, wherein each stored experience comprises a plurality of sets of features, where each set of features has been determined from a previously sensed scene and the stored experiences cover an unbound spatial area, in addition to capturing different appearances of the same area; d) if the extracted set of features of the sensed scene are recognised within any one of the stored experiences then that stored experience is used to produce an estimate of the position of the vehicle at the current time with respect to the stored experience; and e) if the sensed scene is not recognised within more than a predetermined number of the stored experiences then the sensed scene becomes a part of a new stored experience for future comparisons a) capturing data from the sensor providing a sensed scene around the vehicle at a current time; b) processing the sensed scene to extract a set of features from the sensed scene and to estimate, using the extracted features, a position of the vehicle; wherein the estimation is performed by: c) comparing the extracted set of features from the sensed scene to a plurality of stored experiences to ascertain whether the sensed scene can be recognised within any of the stored experiences, wherein each stored experience comprises a plurality of sets of features, where each set of features has been determined from a previously sensed scene and the stored experiences cover an unbound spatial area, in addition to capturing different appearances of the same area; d) if the extracted set of features of the sensed scene are recognised within any one of the stored experiences then that stored experience is used to produce an estimate of the position of the vehicle at the current time with respect to the stored experience; and c) comparing the extracted set of features from the sensed scene to a plurality of stored experiences to ascertain whether the sensed scene can be recognised within any of the stored experiences, wherein each stored experience comprises a plurality of sets of features, where each set of features has been determined from a previously sensed scene and the stored experiences cover an unbound spatial area, in addition to capturing different appearances of the same area; d) if the extracted set of features of the sensed scene are recognised within any one of the stored experiences then that stored experience is used to produce an estimate of the position of the vehicle at the current time with respect to the stored experience; and e) if the sensed scene is not recognised within more than a predetermined number of the stored experiences then the sensed scene becomes a part of a new stored experience for future comparisons