Method and system for using altitude information in a satellite positioning system

DETAILED DESCRIPTION The present invention provides various methods and apparatuses for determining a position of a mobile satellite positioning system (SPS) receiver with the use of altitude information.
In one example of a method of the present invention, a cell object information is determined.
This cell object information comprises at least one of a cell object location or a cell object identification.
In one example, the cell object may be a cell site and the identification may be an identifier of the cell site and the location may be the latitude and longitude of the cell site.
An altitude is determined from the cell object information which is selected based upon a cell site transmitter which is in wireless communication with a cell based communication system which is coupled to (and typically integrated with) the mobile SPS receiver.
That is, the altitude is determined from a cell object information which is associated with the cell site transmitter which is in communication with the communication system of the mobile SPS receiver.
The position of the mobile SPS receiver is calculated using the altitude which is determined from the cell object information.
In another example of a method according to the present invention, an altitude pseudomeasurement is determined, and this pseudomeasurement uses an estimate of an altitude of the mobile SPS receiver.
This estimate of the altitude may be derived from a cell based information source in a cell based communication system or may be an average altitude or other mathematical representation of altitude or altitudes of an area of coverage of a wireless basestation in a non-cell based system.
In one implementation, a comparison of the estimate of the altitude to an altitude that is calculated from pseudoranges to SPS satellites (or from pseudoranges and the altitude pseudomeasurement) determines the condition of at least one pseudorange between an SPS satellite and the mobile SPS receiver.
In another implementation, the altitude pseudomeasurement may be used as a redundant measurement (with pseudoranges to SPS satellites) and fault detection and isolation techniques may be employed using the redundant measurement to determine the condition (e