Abstract: A method and system are provided for minimizing storage and processing of ionospheric grid point corrections transmitted from WAAS satellites in a global positioning system. Based upon a current location, the system creates a boundary around the current location and collects ionospheric grid point corrections within the boundary. The collected correction points are used to correct the position initially determined by a global positioning system.

Abstract: A GPS system device acquires satellites after a power-on event without requiring a need for a real time clock. A list of the highest visible satellites for a given periodic interval is computed and referenced by time. The list can be stored in a non-volatile or battery backed memory during a power off state or can be generated at power up prior to satellite acquisition. When the GPS system device is powered on, satellites from the list are searched using a multi-channel correlator until at least one of the satellites is acquired. The present time is estimated based upon the relationship to the list of the satellite, and satellite visibility is computed. The multi-channel correlator is then updated to search satellites that are likely to be visible based upon the acquired satellite. The search for satellites is further refined by the observation of the handover word provided by an acquired satellite. When a minimum number of satellites are acquired, normal satellite tracking and position computation may occur.