Patent ID: 8188912

Claim:
A method of improving accuracy of position coordinates of a positioning device comprising: (A) obtaining a 3D reference solution for reference position coordinates of said positioning device by using a plurality of available radio signals emanating from an integer N number of available radio sources at time t; wherein said 3D solution includes a reference 3D altitude of said positioning device at Epoch (t); (B) obtaining a barometric altitude of said positioning device at each Epoch; (B4) detecting Epoch (t*) at which a trigger event occurs; (C) if a trigger event occurs at Epoch (t*)=Trigger Epoch (t+1), generating an updated altitude of said positioning device at said Epoch (t+1) by using said reference 3D altitude obtained at said Epoch (t) and by using said barometric altitude obtained at said Epoch (t) and obtained at said Epoch (t+1); and (D) using a position estimator to obtain 3D solution for position coordinates of said positioning device at said Epoch (t+1) with improved accuracy by utilizing said updated altitude of said positioning device.