On 12/06/18 20:04, Leith Bade wrote:
Our receivers work fine in Australia as I live in Canberra and work for the Swift Navigation engineering department. Using one of the free CORS stations here I can get 2cm positions from my car. Mind you the setup cost ~$2000.
This is the bit I'm a bit dubious about. The blurb on GA suggests that we are going to be getting 3cm accuracy from our smart phones, but I'm wondering how the development of GPS antennas small and cheap enough to go into phones is coming along.
Unfortunately OpenStreetMaps only uses "WGS84" as it's datum which is not that well defined compared to a surveying datum like GDA94/2020 or ITRF, and most existing data has only been measured to a few metres (at most). So I wouldn't worry too much about the drift as there are other larger sources of error in OpenStreetMaps.
Reminds me of a paper I read on the the subject where the author pointed out that anyone who says they are mapping to "WGS84" doesn't know what they are talking about. However, I do think you are being a little pessimistic. So long as there is good aerial photography or some external dataset available it's possible to get closer. In Canberra, provided that the mapper traces carefully, you can easily map things to within 0.3m.
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