which USB GPS device should I buy?

[phiscock-g851W1bGYuGnS0EtXVNi6w at public.gmane.org]

> One thing GPSs are NOT good at is altitude.  It was not designed to
> provide that with any kind of accuracy.  If you get +/- 100m you are
> doing well.  GPS is meant to provide position for latitude/longitude
> not altitude.
>
> This is why there are a number of hiking GPS units that have altimeters
> built in to get altitude.  It is much more accurate than GPS will ever be.
>
> --
> Len Sorensen

Not only are they not all that accurate, they are limited to less than
60,000 feet, should you be planning a balloon trip ;). (With oxygen).

http://showcase.netins.net/web/wallio/GPSrcvrsvs60kft.htm

I guess that this is to prevent amateur ICBM builders from navigating
their payload with a GPS-equipped phone.

This is actually relevant for the amateur balloon-telemetry crowd, where
the balloons (un-accompanied by a life form) routinely go above 60k feet.

Peter



-- 
Peter Hiscocks
Syscomp Electronic Design Limited, Toronto
http://www.syscompdesign.com
USB Oscilloscope and Waveform Generator
647-839-0325

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