NMEA

GPS and NMEA Troubleshooting

Contents

  1. I'm not getting any GPS Data

  2. I can't find the right serial port

  3. The GPS makes my mouse go crazy !

  4. The GPS isn't outputting any data

  5. All or some of the NMEA Strings are empty

Answers

I'm not getting any GPS Data

There are several possible causes of this. Either the GPS has no output, the serial port is incorrectly configured, there is a problem with the antenna or there is a wiring problem between the GPS and computer.

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I can't find the correct serial port

If you have no serial ports or too many serial ports in the NMEA Configuration Dialog and are using a serial to USB converter check that the drivers are correctly installer. On Windows machines, look in the control panel for unknown USB devices. If you're having trouble identifying the right port, then it may be worth restarting PAMGUARD with and without the converter plugged in to see which ports appear and disappear from the list in the NMEA Configuration Dialog.

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The GPS makes my mouse/cursor go crazy !

When a Windows PC starts up and a GPS or other NMEA device is connected, the Plug and Play system thinks that a serial mouse or trackball has been installed. The system then starts to interpret NMEA messages as mouse movements. Your cursor seems to jump all over the place and it becomes impossible to control your machine.

To solve this problem either temporarily or permanently, do one of the following:

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The GPS isn't outputting any data

If you're convinced that the GPS is correctly connected any you still aren't getting any data, then it's possible that the GPS has been configured to either not output data at all, to output data in a different format or at a different baud rate.

This is unlikely with marine GPS's, but many hand held devices are set to different communications protocols. Refer to the manufacturers hand book (or jab about randomly at the GPS's menu options) and set it to output data in NMEA 0183 format at 4800 baud.

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All or some of the NMEA Strings are empty

If data are getting into the computer and you can see strings in the NMEA Strings List which are mostly lot's of ,,,,,,,, then the most likely explanation is that you've no satellite signal. Check your antenna has a clear view of the sky. If your GPS has only been switched on for a few minutes and has moved a long distance since it was last switched on it may take some minutes to find satellites. Refer to the manufacturers handbook for further information.

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