Patent ID: 8374786

Claim:
A method of computing navigation information in a portable device, the device comprising a GNSS receiver, wherein the GNSS receiver is arranged to receive navigation signals from a plurality of navigation satellites, and comprises a GNSS processor, to extract a GNSS position information from the navigation signals, the GNSS receiver being further arranged to obtain data from a camera module, the method comprising the steps of: deriving a set of position information using the camera module, by estimating a motion of the device from a sequence of images, the sequence of images recorded by the camera module using a lens; providing the set of camera-derived position information to a navigation processor; using the set of camera-derived position information and the navigation signals, to generate a position fix of the GNSS receiver, wherein a dead-reckoning position estimation mode is acknowledged upon consistency of the set of camera-derived position information with a uniform motion of the GNSS receiver; and computing navigation information based on the generated position fix.