US Patent 8473241 Navigation trajectory matching

Among other things, first data is received from an inertial tracking device worn by a first person, the first data approximating locations along a first path that was traversed by the first person. Second data is received from an inertial tracking device worn by a second person, the second data approximating locations along a second path, similar to the first path, that is being traversed by the second person. A determination is made about how to guide the second person to reach the first person by using the first data and the second data to correlate locations along the first path and corresponding locations along the second path.