[Openstreetmap] GPS reception in narrow city streets

[Schuyler Erle]

* On  3-Mar-2005 at  7:32AM PST, SteveC said:
> * @ 03/03/05 11:42:13 AM f_mohr at yahoo.de wrote:
> > just to repeat my question from january
> > 
> > I still have some problems with narrow city streets where 
> > the GPS accuracy gets realy bad.
> > (several meters offset, left/right jumps on straight streets)
> > 
> > The "London Free Map" page mentions a "window of opportunity".
> > How do i calculate this time window for my location?
> > Is there any tool available?
> 
> Grab some software that models sat orbits, get good gps orbit data, try
> and figure out when you'll get a number of satellites overhead.
> 
> Get the location of the satellites off gps itself and either model the
> orbits or just plot accuracy over 72 hours or more and look for 90
> minute patterns...

I had some software that did this, by scraping the US Navy website at
http://sirius.chinalake.navy.mil/cgi-bin/satpred-query ...
Irritatingly, that site is down now. However, there is a boatload of
useful links at http://www.edu-observatory.org/gps/tracking.html.

I think this can be done with an old package called seesat5 and data
provided by NORAD. I'm looking into this and will let you know what I
find.

SDE