GPS Selective availability turned off

[Robert Smallshire]

> We have a couple of friends here that are working on those lines.
> They say they expect DGPS to be somewhat better than non-SA GPS,
> because it
> would correct things like the atmospheric effect or I don't konw
> which others...

I only have experience of low-end (i.e. Garmin 12XL) and high-end (i.e.
Trimble 4700) GPS equipment - presumably you're talking about mid-range DGPS
equipment - the sort that uses corrections broadcast on FM? Non-SA has made
no differece at all to our Trimble DGPS units - accuracy is still ± 20 mm -
so I would say that DGPS is still several hundred times better that non-SA
GPS.

Rob Smallshire.