Mobile handset location determination integrity maintaining method for cellular communication system, involves transmitting error message to mobile handset when differential correction data are determined

摘要

An error message, produced by differential correction data to identify off-nominal errors, is transmitted to a mobile handset when differential correction data are determined corresponding to the mobile handset's location. A differential correction message, generated from the differential correction data, is transmitted to the mobile handset. The differential correction data is derived based on a differential global positioning system. Independent claims are also included for the following: (a) an assisted satellite positioning system integrity maintaining method; (b) a mobile radio handset location determining method; (c) and a satellite positioning system enabled mobile radio handset.