DETERMINING POSITION IN A HYBRID POSITIONING SYSTEM USING A DILUTION OF PRECISION METRIC

摘要

A method for determining the position of a device in a hybrid positioning system is disclosed. The method includes determining an initial position estimate of a device using a non-satellite positioning system, obtaining satellite measurements from less than four satellites, the measurements including each satellite's position with respect to the initial position estimate, determining a Dilution of Precision (DOP) based on the satellite measurements, if the DOP is small, refining the initial position estimate using the satellite measurements, and if the DOP is large, providing the initial estimate as a final position estimate for the device. The non- satellite positioning system can, optionally, be a WLAN positioning system. The obtaining satellite measurements can, optionally, be from two satellites or three satellites. A method for determining a DOP with less than four satellites in a hybrid positioning system is also disclosed.