GPS stuff
I recently (in July 2008) bought an Openmoko Freerunner. Since that has a GPS and tangoGPS can be used to continually (1 sample per second) record the position in a tracefile, I've started to play around with it a bit.
Some random observations:
- To aquire the first fix, you should not move. I initially tried to get a fix while walking around in Vienna. Even when I walked in a park with no buildings around, TTFF was very long (10 minutes or more). But when I stand still or sit on a bench, I get a fix within 1 or 2 minutes.
- Once the Openmoko has a fix, it won't lose it. Even if it doesn't receive any signals for some time (inside a building or driving through a tunnel), it will get a fix again within a few seconds after reception continues.
- The error seems to be generally within a few meters.
Open Street Maps
I played a bit around with open street maps, and wrote a small perl script to draw a trace onto a map. The tiles are automatically downloaded from t@h.
Here are a few samples: