BaroqueW

I just bought a no-name USB GPS receiver in the Swedish store Teknikmagasinet and it’s up and running on my Mac (Leopard 10.5.1 or Ubuntu via Parallels). Story of an installation.

The device is just a small box, the size of a matchbox, that you can connect using the built-in PS2 cable or using the USB cable extension provided in the package (convenient to place the receiver outside or by the window). The package also contains a CD, note really useful (especially the test application) but it gives a very exhaustive list of the NMEA commands the receiver understands. The GPS chip is a Nemerix (not a Garmin, not a SiRF). For $40 to $60, you can find on Amazon similar USB GPS receivers with various chips and features (waterproof, number of channels, etc.).

First of all, Ubuntu with Parallels. My install is the installation that can be found on the website of Parallels. Remember to connect the USB port to Parallels (Devices>USB>USB-Serial controller) before going any further. Next, go in System>Administration>Synaptics Package Manager under Ubuntu. You can do a search on the string “GPS” and install the packages you feel interested in. At least, you need to install the GPS daemon gpsd and a client: xgps or gpsdrive. Then, start gpsd with ‘gpsd -n -D 3 -p /dev/ttyUSB0‘. If you want to push the envelope any further, go and visit the gpsd web site, otherwise, I provide all the basic informations here. To check your GPS receiver is working, start xgps or gpsdrive. If you see a sort of constellation in xgps representing the various satellites of the GPS system, or if your position shows up properly in gpsdrive, you’re good. If you have a display in xgps but not coordinates on the left side of the screen, it means the signal is too weak. Get the receiver outside or closer to a window, or try to get a clear horizon. To do some debugging, stop gpsd and start it again with ‘gpsd -n -N -D 3 -p /dev/ttyUSB0} to check the messages exchanged between the receiver and the computer. If you see a message saying “satellite data no good”, it means there is no proper reception. See below to screenshots: first, a screen of xgps with a poor reception (“n/a” on the left of the screen) and a screen of gpsdrive with a proper signal (I removed the bottom of the screen that included my coordinates). I didn’t test but this whole setup should be compatible with Kismet.

Now, let’s have a look at MacOSX. The easiest is to start installing the driver for PL2303 (the USB controller for many GPS receivers) on Prolific’s website. Then, install gpsdX, the OSX version of gpsd. Then start the start the application called ‘gpsdX Config’ and choose ‘/dev/tty.usbserial’, the peripheral created by the driver downloaded on Prolific (obviously if you GPS receiver is bluetooth-enabled, just select one of the /dev/tty.Bluetooth devices from the list). Apply the new settings and you now have a gpsd server running under MacOSX! Next step, finding a client. You have two options: gps2geX that interfaces gpsd with Google Earth (even in its free version), or the MacOSX port of GpsDrive developed by VASS-Softwareentwicklung. The first one obviously needs to have Google Earth installed on your computer. To use gps2geX, start GE, then start gps2geX, next click on “Start gps2geX” and here you are: Google Earth is kept updated regularly with your position! On the other hand, GpsDrive requires the installation of X11 from your copy of the DVD of MacOSX Leopard (or Tiger). Note that Gpsdrive is a PPC binary (but runs on Intel computers via Rosetta). The rest is just like under Ubuntu. Last precision, the use of gpsX is compatible (tested) with KisMAC (Kismet and KisMAC are two tools for wireless networks).