GPS Icon Drifts or Appears in Unexpected Locations (254312)

SUMMARY

When you use a Global Positioning System (GPS) receiver with either of the programs listed at the beginning of this article, you may encounter the following symptoms:

The GPS icon may drift even though you remain stationary.
The GPS icon may appear in an unexpected location, such as over water.

These symptoms can occur for a variety of reasons. The most common causes are discussed in the "More Information" section of this article.

MORE INFORMATION

Degradation of Receiver Accuracy

In most cases, your GPS receiver will accurately report your position, but dilution of precision, ghosting, and other factors can degrade GPS receiver accuracy.

Streets & Trips displays the position that the GPS receiver reports and does not try to adjust it on the map to match roads, land, or water features. The GPS icon may not show exactly where you are on the map, but you can expect the GPS icon to appear near where you are.

Signal Strength

GPS signal strength may be insufficient to produce an accurate result. The GPS receiver may also be searching for available satellites with a stronger signal.

Incorrect Map Datum

The map information in the Microsoft programs listed at the beginning of this article is generally based on the World Geodetic System 1984 (WGS-84) map datum.

Because of the methods these programs use to display map information, there may be a discrepancy between the displayed position of a point on the map and the actual latitude and longitude of the point based on the WGS-84 map datum.

Some Global Positioning System (GPS) instruments can be configured to use different map data for their basic map functions. To obtain the best results with Microsoft programs that support GPS input, configure your GPS receiver to use the WGS-84 map datum.

Signal Updates

Because the products listed at the beginning of this article poll the GPS receiver for positioning data every 15 seconds, the GPS icon may appear to lag behind your actual position.