A method and apparatus for determining pose of a transmitter, and by extension the pose of one or more receivers, in an electromagnetic tracking system when the transmitter is allowed to move freely in the physical environment. The method operates in a system that incorporates two separate tracking technologies and an Inertial Measurement Unit, one determining the pose of a device relative to a global reference frame and another determining the pose of the same device relative to a local reference frame, thereby avoiding the latency problem and resulting inaccuracy of pose determinations of known prior approaches.

A heading determination device comprises data input circuitry configured to obtain magnetic field sensor data sensed by a magnetic field sensor in sensor coordinates, position input circuitry configured to obtain a position estimate of the magnetic field sensor, and estimation circuitry configured to derive, from a magnetic map, a local azimuth distortion value in a reference coordinate system at the current position of the magnetic field sensor indicated by the obtained position estimate and to estimate the heading of the magnetic field sensor in the reference coordinate system based on the obtained magnetic field sensor data and the derived local azimuth distortion value.

A heading determination device comprises data input circuitry configured to obtain magnetic field sensor data sensed by a magnetic field sensor in sensor coordinates, position input circuitry configured to obtain a position estimate of the magnetic field sensor, and estimation circuitry configured to derive, from a magnetic map, a local azimuth distortion value in a reference coordinate system at the current position of the magnetic field sensor indicated by the obtained position estimate and to estimate the heading of the magnetic field sensor in the reference coordinate system based on the obtained magnetic field sensor data and the derived local azimuth distortion value.

A method is described in which a plurality of magnetic field norms is obtained using a plurality of magnetic field sensor units, each of the plurality of magnetic field sensor units being arranged to measure a magnetic field at a different height while being mounted to an object, each of the plurality of magnetic field norms being a norm of the magnetic field measured by a corresponding one of the plurality of magnetic field sensor units; and the plurality of magnetic field norms is matched with a magnetic field map of an indoor area including a plurality of sub-areas to estimate a location of the object as one of the plurality of sub-areas.

A method is described in which a plurality of magnetic field norms is obtained using a plurality of magnetic field sensor units, each of the plurality of magnetic field sensor units being arranged to measure a magnetic field at a different height while being mounted to an object, each of the plurality of magnetic field norms being a norm of the magnetic field measured by a corresponding one of the plurality of magnetic field sensor units; and the plurality of magnetic field norms is matched with a magnetic field map of an indoor area including a plurality of sub-areas to estimate a location of the object as one of the plurality of sub-areas.

Systems, methods, and apparatuses for a self-locating compass for use in navigation are disclosed. The self-locating compass is operable to provide position and/or velocity without information from a global positioning system (GPS) device. The self-locating compass includes a direction finder and a Lorentz force detector. The method includes determining orientation with respect to Earth's magnetic field, measuring a Lorentz force proportional to rate of change of location with respect to the field, determining a change in location, and updating location.

A method, computer program, and computer system of a base station is provided for determining a location of a mobile device by receiving data from a mobile device associated with a location of the mobile device and generating a world model database corresponding to a physical location of the base station. The received data is constrained based on the generated world model database, and an updated location of the mobile device is determined based on the constrained data.

A method, computer program, and computer system of a base station is provided for determining a location of a mobile device by receiving data from a mobile device associated with a location of the mobile device and generating a world model database corresponding to a physical location of the base station. The received data is constrained based on the generated world model database, and an updated location of the mobile device is determined based on the constrained data.

In one embodiment, a method includes receiving from one or more magnetic-measurement devices one or more trajectories comprising magnetic measurements in an area collected by the magnetic-measurement devices over a period of time. The method also includes performing one or more correlation analyses on at least some of the trajectories to determine similarities in the trajectories. The method also includes storing portions of the trajectories that have determined similarities below predetermined thresholds for incorporation into a master geomagnetic map.

In one embodiment, a method includes receiving from one or more magnetic-measurement devices one or more trajectories comprising magnetic measurements in an area collected by the magnetic-measurement devices over a period of time. The method also includes performing one or more correlation analyses on at least some of the trajectories to determine similarities in the trajectories. The method also includes storing portions of the trajectories that have determined similarities below predetermined thresholds for incorporation into a master geomagnetic map.