Image Number 2 for United States Patent #7019693.
The altitude of a communications device, which communicates with a communications system via at least one antenna, is estimated. The altitude estimation is based at least on altitude information of said at least one antenna. The altitude estimate of the communications device may be based on a two-dimensional location estimate for the communications device and on information representing three-dimensional location of said at least one antenna of said communication system. The two-dimensional location estimate and the altitude estimate may be sent to the communications device as location assistance information.