Patent ID: 8504292

Claim:
A method for determining a position of a user inside of a structure, comprising: capturing acceleration and orientation data by an inertial motion unit (IMU) affixed to the user descriptive of acceleration and orientation of the user; capturing range data by one or more range finders affixed to the user descriptive of distances from the user to physical constraints within the structure; producing an estimate of the user's relative displacement based on the acceleration and orientation data captured by the IMU; generating a cloud of particles within a model of the structure based on the estimate of the user's relative displacement, wherein each particle of the cloud of particles represents a possible position of the user; applying one or more particle filters to the cloud of particles to eliminate any particles of the cloud of particles that violate physical constraints, and eliminate any particles of the cloud of particles that are inconsistent with the range data captured by the one or more range finders; and applying a statistical function to the cloud of particles to determine a calculated position of the user.