> > I was under the impression that you still need those reference > stations for doing surveys, because of those atmospheric conditions > you mention. >
A reference station is really just a receiver that doesn't move and is well surveyed in. You can use a reference station if you have one close (say less than 20km), use a virtual reference network (normally a bit pricey) or use a second unit (aka 'base') as the reference station. When you are using a pair of receivers your system is really just giving you the deltas in position, which is why you would place the base above a survey marker in the pavement/sidewalk. You can even get pretty good results using just an L1 receiver, say 5cm with good antenna/reception but will have a much more limited baseline length. Simon. _______________________________________________ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
