Anyone had luck with PPK under forest canopy (leaf off)? I was tasked with cross sections on a 1.1 mile new construction timber road with required relative positional accuracies of around 1'. I was contemplating dual frequency gps rather than traditional compass, clino., and tape. Thoughts?
I have had good luck on manholes (did a check with TS)using 15 min. static and post processed. I had 1 bad point out of 64 and it failed in post process. Using Hyper + with Glonass.
Well I wouldn't be too confident in any solution you get, I have quite a few thousand utility locates on my resume using RTK/PPK, in trees it is certainly a gamble.
Float may or may not get you a foot, and it is tough to get fixed ambiguities in the trees. I would almost rather say either static or RTK and static probably isn't practical for X-sections.
With RTK, you might be able to tell in real time if your QC is going to be under a foot. The problem with PPK is you have to guess on the initialization and then make darn sure as you walk the X-section that your DOP's and number of SV's are OK and if not, then you have to have enough data at the next X-section point to reinitialize the chain and of course you never really know until you get back to the office and PP the data.
Best bet would be to run a X-section or two and then check with a TS and see if in general it is going to work using GNSS gear of if some other tool might be better.
SHG
Never tried it nor seen it used equipment in above link. Looks interesting.
Wihout redundancy, I would find it very difficult to trust data obtained under canopy via satellite-based positioning system.