Troubleshoot using GPS receivers

This topic contains information about how to troubleshoot problems that can occur when you configure and use a Global Positioning System (GPS) receiver with MapPoint.

Troubleshoot configuring a GPS receiver

When I connect my GPS device to my computer, the New Hardware wizard prompts me to provide the location of the device driver.

Special software for a GPS device, called a device driver, is installed automatically as part of the MapPoint installation process. If necessary, you can install the device driver separately as detailed in the following procedure. For example, if you connect the GPS device to your computer prior to installing MapPoint, you will be prompted for the location of the device driver.

To install the GPS device driver when prompted

  1. Put the Setup disc in your DVD drive. If you are prompted to reinstall or remove MapPoint, click Cancel.

  2. Browse to D:\GPSDrvrs (where D is the name of your DVD drive).

  3. Look at the back of your GPS device, and then do the following:

    • If the manufacturer of your GPS device is Navation, click the Navation directory.

    • If the manufacturer of your GPS device is Pharos, click the Pharos directory. Then, if you are using a 64-bit edition of Windows, click the 64 directory. Otherwise, click the 32 directory.

    • If your GPS device does not have either name on it, contact the manufacturer to obtain drivers for your device.

  4. Click Next.

My GPS device is not recognized when it is connected to my computer.

When you use your GPS device with MapPoint, the device must be configured to use a communications (COM) port below 256, and a COM port of 20 or below is recommended. MapPoint does not recognize devices assigned to COM ports above 256 as GPS devices.

To make sure that you have selected the correct port

  1. Connect your GPS device to your computer.

  2. In the GPS pane, click Configure GPS to open the GPS Receiver Settings dialog box.

  3. Click Scan to scan the ports on your computer for available GPS devices. When the process is complete, the text GPS device found appears next to the name of the port to which the GPS device is connected.

  4. Select that port from the list, and then click OK.

Some information in the GPS Sensor window is unavailable.

Some GPS receivers can be configured to transmit only a portion of the information that is available. Data is transmitted from the GPS device to your computer or mobile device in the National Marine Electronics Association (NMEA) 0183 output format, which is called an NMEA sentence. In general, a particular NMEA sentence equates to a particular parameter, such as altitude. Check your GPS receiver to see whether any NMEA sentences are turned off. For more information, see the documentation that came with your GPS receiver.

Troubleshoot your GPS receiver and MapPoint

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

Make sure that your GPS receiver is turned on, and then check the following items. If problems continue, contact the manufacturer of the device.

  • Verify that the GPS cable is plugged into the COM port on your computer and is working properly.

  • Make sure that the input/output format (interface) on your GPS receiver is set to support the NMEA 0183 version 2.0 or later format. For more information, see the documentation that came with your GPS receiver.

  • Make sure that you have installed the device driver for the GPS receiver on your computer. For more information, see the documentation that came with your GPS receiver. If you are using a Microsoft GPS receiver, the driver is installed when you install MapPoint.

  • Make sure that the COM port is set to the same speed as the GPS device. For most devices, 4,800 bits per second (bps) is the correct speed. For more information, see the documentation that came with your GPS receiver.

  • Make sure that the COM port that was selected during configuration is the same port that your GPS receiver is connected to. In MapPoint, on the Tools menu, point to GPS, and then click Configure GPS receiver. Or, in the GPS pane, click Configure GPS. In the GPS Receiver Settings dialog box, click Scan to scan the ports for a GPS device. When the device is located, click OK.

  • Close other programs that use the same COM port, or change the program settings so that the programs use a different COM port from the one you configured for the GPS receiver.

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

  • Try using COM port 20 or below. Although MapPoint may work with a device attached to a COM port up to 256, the recommendation is to use COM port 20 or below.

Note   Advanced users can use HyperTerminal to investigate the problem. For more information, see the online Help for your operating system (for the Windows XP and Windows Vista operating systems, click Start, and then click Help and Support).

The application cannot find GPS satellites.

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

Also:

  • Make sure that your GPS receiver is 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. This search can take up to 14 minutes.

  • Verify that your GPS receiver is properly attached to your computer, and that the antenna, if the receiver has one, is tightly connected to the GPS receiver.

  • Make sure that there are no obstructions between your GPS receiver and the sky. If you are inside a building, surrounded by tall buildings, in a tunnel, or in the presence of similar obstructions, your GPS receiver may not be able to get clear signals. Because the GPS receiver requires signals from at least three satellites, even partial obstruction (such as very tall buildings) can prevent your GPS receiver from functioning properly.

The GPS symbol appears off the road or in water on the map.

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

When you're using a GPS device to track your current position, MapPoint displays the position that the GPS receiver reports and does not attempt to adjust it on the map to match roads, land, or bodies of water. The GPS icon may not indicate your exact location, but you can expect the GPS icon to appear near your location. If you select the Provide navigation check box in addition to clicking Start/stop GPS tracking in the GPS pane, MapPoint adjusts the position reported by the GPS receiver to snap it to the route.

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

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

Because of the methods that MapPoint uses to display map information, you may notice a discrepancy in the 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 get the best results with Microsoft programs that support GPS input, configure your GPS device to use the WGS 84 map datum.

The altitude that appears in the GPS pane or GPS Sensor window is not my actual altitude.

Most commercial GPS receivers report altitude accurately to within 50 feet. When there are obstructions between the GPS receiver and the sky, even a clear obstruction such as a windshield, the variance is likely to be greater.

Most GPS units use a mathematical model to approximate the geodetic model of the earth. Altitude is then determined in reference to the approximate mathematical model. Because the earth has an irregular surface that results in a complex shape, some margin of error is likely.

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