On Saturday 28 Jun 2008 10:42, Kenneth Gonsalves wrote: > On 27-Jun-08, at 1:15 PM, jtd wrote: > >> better to use a laser range finder for this - gps wont cut it > > > > Sort of True. Survey quality gps will give you repeatability - > > the offset will be consistent and the distance between two points > > over a few Km will be accurate. But the position wrt to a > > standard survey may be way off. Thus results (conventional survey > > or gps) are open to interpretation. > > I tried to do a couple of golf courses with gps - total failure. > With the laser range finder (and not a very expensive one, I was > able to get accuracy within a yard - which is acceptable for a golf > course.
You should get upto 2.5 m with a 32 ch device. Of course only twelve are used. but it picks a good mix of overhead and horizon sats. try by keeping the reciever still on the ground. For higher accuracies survey quality gps. You should get accuracy of 1 mm/Km. Also by fixing two points accurately on the periphery by non gps means, you could get a deviation figure and correct your readings. You will have to take the correction every few hrs as ionospheric delays vary with sun activity. I have only a vague understanding of the issues involved so dont bet the house on data from this thread. -- Rgds JTD -- http://mm.glug-bom.org/mailman/listinfo/linuxers
