For starters, I've tried to make this as complete as possible but still keep it concise, since documentation on this GPS is fairly scare, and what little documentation there is is usually based on HAM radio usage. So, having little experience with GPS and serial ports, this has taken me literally months (off and on) to figure out. I'm writing this in the hope that some other linux user (Ubuntu or not) will find it helpful, and if you do, please let me know.
The Delorme Tripmate is an older NMEA-compatible serial port GPS from Delorme, that is now available fairly cheap from places like eBay (~$50 USD, mine was $10 at a yard sale). However, trying to use programs like GPSd and GPSDrive right out of the box results in failure (timeout from GPS). Since this GPS doesn't have a power switch, it requires the string "ASTRAL" to be sent to it before it will start broadcasting coordinates. If that helps you, great! Otherwise, if you're like me and have no idea what to do now, read on:
Starting from the very beginning, get gpsdrive. I've never gotten this to work with GPSd, if anyone can tell me how, it'd be awesome, but IMO, gpsdrive is the only usable linux GPS client anyways:
Code:
$ sudo apt-get install gpsdrive
Now, run gpsdrive (not as root)
Click the preferences button and then the "Settings 2" tab, and you should see a box that looks something like this:
Notice the check box for "Use serial conn." is checked, and Baudrate is set to 4800, you will need to mimic these settings. If you're interested in the others, read the gpsdrive manpages, but don't check them off, especially not the GARMIN or Earthmate settings. Interface should be set to your serial port interface; /dev/ttyS0 is usually the first serial port, or /dev/ttyUSB0 for most USB-to-serial adapters (like mine). If you don't know where your GPS is connected to (ie what serial port), scroll down to the bottom, first entry in the "Side Notes" section. Once you've got that set, it's time to see it in action. First, head outside, GPS doesn't work very well inside, even near windows. I'm writing this from my car, with the Tripmate on the dash, and getting decent (but not great) signal.
Code:
For serial:
$ sudo echo "ASTRAL" >> /dev/ttyS0 && gpsdrive
or for USB:
$ sudo echo "ASTRAL" >> /dev/ttyUSB0 && gpsdrive
From what I can find, the Tripmate has a timeout for the ASTRAL string, if a program doesn't open a connection to it, it will revert back to sleep mode very quickly, so I reccomend running it as a single string. Also, if you're still a somewhat of a noob like me, notice that only the "echo" command is being run with root privileges, gpsdrive should not be (and will warn you if you do).
For my USB connection, I made this (really!) simple script:
Code:
#!/bin/bash
if [ -e "/dev/ttyUSB0" ]; then
gksudo echo "ASTRAL" >> /dev/ttyUSB0
gpsdrive
else
echo "GPS is not connected!"
fi
This basically checks if the GPS (WARNING: or any USB communication device, like a usb modem or cell phone) is connected, and if it is, sends the string and starts gpsdrive, otherwise it exits. If you want to use this, copy it into a text file, save it, and then run "$ chmod +x <file>". I then put it in /usr/bin, and created a link on my panel to it. Gnome even has an icon, "gpsicon.ico" in /usr/share/pixmaps.
Using GPSDrive: The Basics
This is by no means a full tutorial, just enough to get you started. By default, GPSDrive will open with a map of some area of Germany. Once the "Not enough satellites in view" message at the bottom disappears (this will take several minutes the first time, and about a minute each time after), move the slider at the left to get to a world map, and if you live in the US, it will probably show your location as being somewhere in outer space. DON'T PANIC!. Click the "Download Map" button, and then select a scale of 2000000. This should download a fairly large (state-size) map around your GPS's current coordinates. From there, you can download higher detailed maps of your location, and use the "Pos. Mode" to move the map focus and get maps of other areas. You can also set waypoints using CTRL-click, and map out trip routes. From here, you're on your own!
Known Problems:
GPSDrive at times doesn't like to close when using a direct serial connection (ie not using gpsd), at least with this GPS. Closing with the close button on the top bar will result in Gnome complaining about it not exiting and a Force Quit option, and using the Quit button will hang. The best option is using the close button at the top, and then selecting Force Quit.
When closing and reopening GPSDrive, the Tripmate will sometimes stay in sleep mode. I have no idea why, it just does. Just close and reopen gpsdrive (with the astral string or your script) a few times, and it should eventually work.
*Side Notes*
Some other Tripmate-related things I found out while researching that don't apply to me, but might help other users.
"Finding" your GPS:
Figuring out which serial port your GPS is connected to sometimes isn't as easy as it sounds. Ubuntu automatically sets up /dev/ttyS0 as your first serial port, /dev/ttyS1 as the second, etc. But some hardware manufacturers do odd things and the first physical serial port isn't necessarily the first hardware one. If GPSdrive still reports it can't find your GPS after following the guide, use the ASTRAL to your advantage. ASTRAL is being constantly sent out by the GPS, so with
you should be able to see the ASTRAL string (use CTRL+C to exit). If not, try ttyS1, 2, and 3. If you still don't get an ASTRAL, check your batteries, or else it be that your unit has been modded (see below), your serial port is disabled in the BIOS, or your Tripmate is just plain dead.
If you know how to work with serial ports, you could probably create a script or program that checks for the "ASTRAL" string incoming on a serial port (the Tripmate broadcasts this constantly while in sleep mode), but that's beyond me.
Alternative power options:
The Tripmate, like many GPS's, eats batteries. here is a tutorial to create a power adapter to plug into your cigarrette lighter, or here you can find info on supplying power from your laptops keyboard/mouse connector. Personally, I have a lighter adapter from a PSP ($1 on clearance at walmart, supplies 5v, 2A) connected directly to the wires from the battery terminal.
Hardware mod:
This mod removes the necessity for the "ASTRAL" string to be sent to the GPS by routing the ASTRAL sent by the GPS while in sleep mode back to itself, so it's essentially on any time there's power. If this sounds like your cup of tea, and you've got a steady hand with a sodiering iron, check it out here
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