GPS Troubleshooting: This process ensures that the GPS unit and the Computer have established successful communications with each other
When Terrain Navigator isn't getting the GPS data during navigation, it's a good idea to check outside of the application to be sure the serial port is receiving the data. If the ports do not see any GPS data coming in, then Terrain Navigator will not be able to see the signal. HyperTerminal, one of the programs which is included with Windows, is a useful troubleshooting utility, since it reads any information being received by the system through any available COM port. Here are the steps:
Notes Before we get Started
- Terrain Navigator, and all other programs, especially any that use COM ports for other connections, should be closed while running the HyperTerminal program.
- If you are using a Garmin GPS, the GPS should be set to its NMEA mode in its Interface Setup area for this test. Once everything is working, you may wish to switch to Garmin interface mode for transfer of routes, waypoints, and tracks.
- The GPS should be set to its Simulator mode if indoors or having difficulty obtaining the GPS satellite fix.
- If you have other devices (such as a PalmPilot) that use the same serial port, ensure that the device's software (most commonly called HotSync) is disabled.
- If your computer is lacking a physical serial connection, you are probably using some sort of USB-to-Serial adaptor. Be sure that the drivers included with this adaptor have been installed and are working properly.
Performing the HyperTerminal Test
1. Click Start, then Programs, then Accessories, then Communications, then HyperTerminal
2. If a window comes up asking if you want to configure a modem now, select "No" or "Cancel". If required to enter an Area Code, do so. Otherwise, proceed to the next step.
3. Another window titled "Connection Description" appears. In the Name: box, type in the letter t for "test". Click on OK.
4. Another window pops up with the title "Connect To". The only field of interest here is Connect Using:, which must be set to "COM1". (If COM1 is not shown, select COM2, or whatever is the least-numbered COM port.) Click on OK.
5. The window "COM1 Properties" appears. The only field to change here is Bits per second:, which should be set to "4800", since the NMEA 0183 standard specifies 4800 baud rate. Click on OK.
6. The main white HyperTerminal window becomes completely visible.
At this point, one of three things can happen:
I get an error message.
This means that the COM port you have selected is not available or functioning properly. Close HyperTerminal and repeat the process, trying a different COM port. (Repeat the above steps for other COMs, replacing COM1 with whatever COM ports are available on your PC.) If none of these will reveal GPS input, then the problem lies in the physical serial port, the USB-to-Serial adapter cable (if used) the GPS receiver, or the connection between the two. ) If you are certain that you are selecting the proper COM port, contact your computer (or USB-to-Serial adapter) manufacturer for further troubleshooting tips.
I get a blank screen with a flashing cursor.
This indicates that the COM port you've chosen is not currently receiving NMEA data. Close HyperTerminal and repeat the process, trying a different COM port. (Repeat the above steps for other COMs, replacing COM1 with whatever COM ports are available on your PC.) If none of these will reveal GPS input, then the problem lies in the physical serial port, the USB-to-Serial adapter cable (if used) the GPS receiver, or the connection between the two. ) If you are certain that you are selecting the proper COM port, contact your computer (or USB-to-Serial adapter) manufacturer for further troubleshooting tips.
I get a screen with text scrolling upward.
You're successfully connected to your GPS unit! Good GPS data will resemble the following:
The data you see scrolling by indicates your current position (among other things). Note the COM port used and exit HyperTerminal. When asked if you want to disconnect now, click on Yes. When asked if you want to save session "Test", click on No.
7. When finished viewing the screen, select "Exit" from the File menu. When asked if you want to disconnect now, click on Yes. When asked if you want to save session t, click on No.
Finishing the Job: Reading the GPS Stream in Terrain Navigator (or Terrain Navigator Pro)
1. From the 'GPS' menu, choose 'GPS Setup Wizard'.
2. Follow the on-screen instructions.
(If the GPS Wizard can not detect the GPS, select 'Setup' from the 'GPS' menu. Set the 'Manufacturer' to 'NMEA - generic' and specify the COM port determined during the above test. Also, ensure that the correct baud rate of the GPS is selected in Port Settings. Then press 'Close')
3. Once the signal is detected, choose 'GPS Tracking', 'Start Tracking' from the 'GPS' menu.
Related Technical Document: Configuring Terrain Navigator (or Pro) to the GPS - Basic Instructions.
Q: I can't find HyperTerminal. How do I install it on my machine?
A: Click here for the MTTTY alternative. (HyperTerminal is no longer included with Windows Vista or Windows 7.)
Q: I can't get HyperTerminal to display the NMEA strings.
A: If you cannot get HyperTerminal to display the NMEA strings after following the above procedure, trying each COM port, there is something wrong with either your COM port, data cable, the USB-to-Serial Adaptor (if required) or GPS unit. Since the problem lies outside of Terrain Navigator, you should contact the manufacturer of these devices for further troubleshooting tips.