主权项 |
1. A method comprising:
receiving, by a processor of a mobile device and from a global navigation satellite system (GNSS) receiver, an estimated position of the mobile device, the estimated position including estimated geographic coordinates and being associated with an uncertainty value; receiving geographic feature data, the geographic feature data including locations and heights of geographic features that are located sufficiently close to the estimated position to interfere with signals received by the GNSS receiver; determining, based on at least one of the locations of the geographic features, a count of the geographic features, or the heights of the geographic features, a lower bound of uncertainty of the estimated position that is achievable by the GNSS receiver when the GNSS receiver is located among the geographic features; and designating a representation of the lower bound of uncertainty as a new uncertainty value of the estimated position, including increasing the uncertainty value upon determining that the uncertainty value has smaller error margin than the lower bound of uncertainty. |