Troubleshoot using a GPS receiver

Article
11/16/2006

I get an error message when I try to track my position with GPS.

Check that the GPS cable is plugged into the communications (COM) port on your computer and is working properly.

Make sure your GPS receiver is turned on.

Make sure the input/output format (interface) on your GPS receiver is set to support the NMEA 0183 version 2.0 or later format. Check your GPS receiver manual for details.

Make sure the COM port is set to the same speed as the GPS device. For most devices, 4800bps is the correct speed. Consult your GPS manual for the correct speed for your device.

Make sure the COM port that was selected during configuration is the same port that your GPS receiver is actually connected to. On the Tools menu in MapPoint, point to GPS, click Configure GPS Receiver, and then select a different COM port from the list if necessary.

Close or change the program settings for other programs that use the same COM port you have configured for the GPS receiver.

Make sure that your GPS device does not require a specific mapping program to work properly. Some GPS receivers can only be used with specific software packages.

Make sure that your GPS receiver connects to a serial port. MapPoint cannot detect GPS receivers that connect to the PCMCIA slot in your computer.

When you use your GPS device with MapPoint, it must be configured to use a COM port below 20. COM ports above 20 will not be recognized as being a GPS device by MapPoint.

If problems continue, check your GPS receiver manual or contact the device manufacturer to ensure that your device is working properly.

Note Advanced users can use HyperTerminal to investigate the problem. For more information, consult your operating system Help file (on the Start menu, click Help).

The program can't find GPS satellites.

Confirm that you have properly installed your GPS receiver, and that you are using the correct COM port.

Make sure your GPS receiver has been turned on, connected to your computer, and running for several minutes. Many GPS receivers must do an initial "sky search," during which they identify satellite signals and start receiving data.

Check that your GPS receiver is properly attached to your computer, and that the antenna is tightly connected to the GPS receiver.

Be sure that your antenna has a direct line of sight to the sky. If you are inside a building, surrounded by tall buildings, or experiencing other line-of-sight obstructions, it could prevent your GPS receiver from getting clear signals from three satellites.

Note If you are using your GPS receiver for the first time, or if you have moved to a new location, it can take up to 30 minutes for your GPS receiver to determine your position.

The GPS icon appears off the road or in water.

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

MapPoint displays the position that the GPS receiver reports and does not attempt 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.

My displayed position is different from the actual latitude and longitude.

MapPoint maps are based on the World Geodetic System 1984 (WGS-84) map datum.

Because of the methods these programs use to display map information, you may notice a discrepancy in 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 GPS receivers 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 instrument to use the WGS-84 map datum.

My GPS device isn't recognized when it is connected to my computer.