RTK Maximum Distance For Topo Survey

my sokkia radian dealer says that RTK is possible to reach above 10 km using radio/cell.
i have used RTK in the past for topo survey but the base is located less than 500m-1km away via radio link.
a client was asking me if it is possible to cover a topo/hydro several kilometers away from base - 5km-10km?

anyone tried doing this? what will your vertical accuracy be in the 10 km range be? I am asking for actual not product specifications.

when we were doing bathymetry survey with rtk, post processing from 2 base units still results in points with deviation in the >10 cm.
and the distances are less than 2km away.

thanks.

RTK is certainly capable of those distances. It would depend on the receiver and the type of communication between the base and rover.

A single frequency base and rover with low power radios would not offer that type of distance between base and rover (more of a line of sight solution), however, if you had a Pac Crest 35 watt radio (or similar hardware) you could push 5-10km, but that would be in a perfect environment with minimal obstructions and your ability to maintain fix/lock would be a bit more difficult. Also your TTFF (time to first fix) could be extended if you do not have optimal control spread through the project. 

Dual frequency receivers (with a high power radio, like a Pac Crest 35 watt radio) would be better suited for a project of that size and trying to maintain that long of a distance between base and rover.

if it really is a Radian ( and not a Radian IS) then you should be aware that it will not give a fixed RTK solution for vectors over 10km. this is  a hardwired threshold value.

More recent receivers can easily go beyond 10 k - your limitation is usually the range of the datalink.

best regards,

Paul

Hi everyone
Thanks for the replies.

Maybe a better question would be - 

At 10km will the elevation values from the rover unit still be reliable to topographic survey points?
If I will be making a contour map from the RTK points will the contours still be a good representation of the actual terrain?
I was under the impression that as RTK rovers are farther away from the base, errors in vertical (and horizontal) will be
increasing thus affecting the point's elevation values.

Thanks.

I do not know anything about the Radian receivers or the options they contain, but you are correct, in a base/rover solution, the further from the base station you increase the PPM error assocaited.

I would suggest testing your setup and configuration to see if it will meet your project accuracy needs.