US Patent 7706976 Position based velocity estimator

A method of determining speed and heading of a rover/rover having one degree of freedom comprising the following steps: (A) determining a rover position coordinates using at least one source of a radio position measurements; (B) storing a set of statistically different rover points in a memory block, and (C) using a subset of rover points including a plurality of stored rover points and a current rover point to determine a speed and a heading of the rover. It is assumed that each rover point comprises a time Epoch and a rover position determined at time Epoch, and that each pair of statistically different rover points comprises two rover positions separated by a statistically significant distance.