Patent ID: 6839631

Claim:
A method, comprising: receiving Space Based Augmentation System (SBAS) correction messages from a selected SBAS satellite; determining whether at least one criterion is satisfied for using the selected SBAS satellite as a correction source; and upon determining that the at least one criterion is not satisfied for using the selected SBAS satellite as a correction source, selecting a second SBAS satellite to be used as a correction source from which to receive SBAS correction messages, wherein determining whether at least one criterion is satisfied for using the selected SBAS satellite as a correction source includes determining whether the SBAS correction messages received from the selected SBAS satellite are reliable, and wherein determining whether the SBAS correction message received from the selected satellite is reliable includes: determining whether the SBAS correction messages received from the selected satellite are less reliable than SBAS correction messages received from the second SBAS satellite; and upon determining that the SBAS correction messages received from the selected satellite are less reliable than SBAS correction messages received from a second SBAS satellite, determining whether a stability threshold is exceeded.