A good introduction to GPS technology (Global Positioning System) can be found in the GPS Tutorial of Trimble . The horizontal position accuracy is degraded to about 100m through Selective Availability by the american DoD. More about the achievable accuracies with different receivers can be looked up in GPS accuracy . The results of that uncertainty are shown in SA - The Movie . For own experiments you can use the SA Watch software under Windows 95.
If you want to make your own cable for the external power and the data communication with a computer you can find a suitable connector at Purple connector .
With its 12 channel parallel receiver the GPS-II Plus works very well on the dash of my car with the built-in antenna. Nevertheless I bought the tiny Lowe Electronics magnetic mount active antenna and placed it on top of the car. With the better reception the GPS works good even in difficult conditions like in the forest and the accuracy of the displayed and stored positions will be improved.
GPS-II+ and a 2m/70cm transceiver in the car
For displaying stored tracks and planing routes at this time I use Navigate GPS . Using it online it often hangs but for displaying trackslogs and creating routes it can be used if you have managed to overcome some pitfalls. For me it has the advantage that it is a 16 bit Windows program and runs under OS/2. For Windows-95 you can use Fugawi , but I had some problems with their demo version. I have now registered OziExplorer , and I'm happy with it, besides the fact that I have to boot my notebook under Windows-95. Creating routes is not as easy as in Navigate but this should change in a future version.
Scanning and adjusting topographic maps is some work but afterwards you
have maps in the desired quality and resolution. In the meantime there are
75MB of maps on my notebook . . .
GPS on my Bike
And that's the GPS receiver on the handle bar: