GPX as submission format (Was: [Openstreetmap] london free maps...)

[Matt Amos]

On Wednesday 17 November 2004 10:58, Petter Reinholdtsen wrote:
> [Matt Amos]
> > having actually read the format in detail i can say: it does
> > support PR and ephemeris, in the extensions field. PR
> > (pseudo-range) is a measure of time for signals to reach you from
> > each satellite. its the raw data from which the GPS unit
> > calculates your
> > position. ephemeris is positional data about the orbits of the
> > satellites.
>
> Sounds good.  Do I understand you correctly when I believe
> collecting the pseudo-range and ephemeris will allow us to
> post-process the collected data with DGPS information to make it
> more accurate?

thats exactly right. you need the PR/ephemeris from the unit and 
similar data from a ground listening station. GPSTk will do this as 
long as the input is in RINEX, but it can't be that hard to hack 
GPSTk to accept GPX+.

> I have no idea if my GPS support this, but will try to find out.

the best thing to do is to look at the spec sheet of your model on the 
manufacturer's page and see if that gives any clues.

cya,

matt
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