Question. If you take a "consumer" GPS, and walk/drive along a path many times enough. And you could somehow average up all those readings ... would the average gives you accurate results ?
On 8/6/07, stephen white <[EMAIL PROTECTED]> wrote: > > On 06/08/2007, at 11:13 AM, Ben Discoe wrote: > > 5. Using the timecode to correlate, subtract the second unit's > > drift from the first unit's coordinates. > > I can't see how you would do this, because you wouldn't be able to > tell the difference between movement and drift. The second unit would > be drifting around at random, rather than having a fixed offset that > you can add or subtract from the first unit. > > > But it should be a really simple operation to subtract one track's > > offset from another. Is there some reason this simple approach > > wouldn't work? Is there some FOSS which will do it? > > I would need to know the situation where you need that level of > accuracy before I could recommend a range of possible solutions. > There are basically no solutions that let you walk around with > accurate tracking no matter how much you spend. You need to pick the > solution based on the strong points, then wrap the rest of the > package around fitting to those points. > > For example, I use orthorectified aerial maps along with photographs > to get about 5cm accuracy at selected points. That technique doesn't > work indoors (obviously) so I have to shift to other methods like > camera calibration and triangulation to extrapolate a series of > photographs through scenes. This too would not work for extended > scenarios due to accumulative error. > > The combination of the two inferior methods achieves what I want as > the aerial imagery provides the broad scale accuracy, limiting the > indoors extrapolations to short stretches from the front door. > > -- > [EMAIL PROTECTED] > > > _______________________________________________ > Geowanking mailing list > [email protected] > http://lists.burri.to/mailman/listinfo/geowanking >
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