[clug] Looking to buy a GPS

[David Tulloh]

matt at kororaa.org wrote:
> Hey Cluggers,
>
> I'm interesting in getting a GPS, one that can both be used in Car and
> hand held.
>
> I know nothing about em, can anyone suggest a model or brand?
> Are there any open GPS's or are they all closed?
> Which ones have good linux support etc.
>   
The best in car GPS units will hook into the car's systems, this way 
they can use the car's tacho to do dead reckoning to supplement the GPS 
results.  The new ones come with accelerometers to do the same sort of 
thing without requiring the extra wiring, I'm not sure if they have been 
released yet though.
None of that is really required around Canberra, it's useful in the 
Sydney CBD but your basic GPS should cope anywhere except near a bunch 
of sky scrapers.

I'd pick one that looks and feels good.  I've been told that 95% of them 
use the same 2-3 GPS bits, so they are really differentiating on the 
aesthetics and the maps.
If you are looking at using it in the US keep in mind that you may have 
to buy an additional map kit or kits for that area.  The map prices 
probably vary widely between companies.

As normal with electronics I'd suggest that you keep away from the 
cheapest noname unit, there's dozen of areas that they could compromise 
to save a few bucks.  This could mean slow startup (a few minutes if 
they do old-style acquisition), slow updates, poor S/N resulting crap 
tracking etc.  You couldn't figure any of this out by looking at the 
marketing on the box.

There are no open source GPS units that I have heard of.  The most 
common communication protocol used is NMEA, all the Linux programs I've 
seen will talk to a NMEA device, several of them talk additional 
protocols.  If you get a unit that will talk NMEA down a serial (or USB 
pretending to be serial) link then it should work with Linux.  I wasn't 
overly impressed by any of the applications I tried, but I was more 
looking from a diagnostic and development perspective.


Please note that these are general GPS comments, I've never tried to buy 
a GPS unit and have never used a commercial end product GPS unit.  
Building one into my car is a future project, unfortunately the list of 
future projects is kinda long.


David