StugeronSteve
Well-Known Member
[ QUOTE ]
and it's back to vanilla dgps
[/ QUOTE ] Does the flavour make a big difference then?
and it's back to vanilla dgps
[/ QUOTE ] Does the flavour make a big difference then?
Question about chart datum
- Thread starter mel80
- Start date
tome
Well-Known Member
It's about 1.5 to 2.5 times as weak in the vertical plane as it is in the horizontal. 3mm is pushing it!
1cm + 1ppm * baseline equates to 2cm CEP at 10km range
The gps receivers we use give us 20 fixes/sec at this accuracy so good for measuring vehicle/vessel dynamics and requires very little filtering
1cm + 1ppm * baseline equates to 2cm CEP at 10km range
The gps receivers we use give us 20 fixes/sec at this accuracy so good for measuring vehicle/vessel dynamics and requires very little filtering
tome
Well-Known Member
You wouldn't want a raspberry would you?
mel80
Well-Known Member
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But chart datum will be known, as will the hight of the satellite. So not to hard to work out.
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Understand that; it was the process by which chart datum goes from not being known to being known that was puzzling me. Anyway, thanks for all the replies; I've got a much better idea of how it's done than I did before. Still not entirely clear how the depth of the 'benchmarks' that tome mentioned are determined, but perhaps we'd best leave that for now!
But chart datum will be known, as will the hight of the satellite. So not to hard to work out.
[/ QUOTE ]
Understand that; it was the process by which chart datum goes from not being known to being known that was puzzling me. Anyway, thanks for all the replies; I've got a much better idea of how it's done than I did before. Still not entirely clear how the depth of the 'benchmarks' that tome mentioned are determined, but perhaps we'd best leave that for now!
Cornishman
Well-Known Member
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This means that it only fits the earth in odd places
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What about the even places?
This means that it only fits the earth in odd places
[/ QUOTE ]
What about the even places?
tome
Well-Known Member
Well Cornwall is an odd place but it still doesn't fit! Sea level Falmouth will give a WGS84 height of about 53m
Watch out that will be those froggies trying to sneak the meridian back to Paris.