Hello Peoples,
Need the lowdown on accuracy of vehicle based scanning - what tolerance, how the data is collected and processed - RTK, PPK etc - how good do you think it is personally?
Thanks
Paul
Ask Mr Google...
Gidday Mate
I believe that there are firms driving roads for design work .
When I was looking into scanning I saw quite a bit of literature on what you asked about.
BTW ...Were/ are U rocked by the Irish bubble burst?
RADU
What accuracy/precision do you want?
If you're asking about the georeferenced element of the data across the entire project (rather than adjacent points in the point cloud), it depends on how much work your willing to put into the project.
Most systems are scalable, so one vehicle driving down the street may be just using WAAS + L1 GPS to get "GIS" grade locations while the next guy could be using L1/L2 GNSS and post-processing the data with network GNSS data in addition to setting control and targets every thousand feet along the road and doing an entire adjustment of the project to get survey grade results.
I think the right system, using the right methods, run by the right surveyor is real close to being able to achieve results comparable to field run topography. I've seen comparisons of the point cloud generated TIN to field located "check points" that have an RSME of about 0.05' in the Z.
Ask Mr Google...
Rocked RADU? How about lined up, shot at down and left out to the carrion.... lol!
We have just us 3 principles left and 2 ladies doing the books on 1 morning a week each. Bit of a comedown from nearly 15 here 2 years ago. We let the last one go 15 months ago....
Work is hit and miss but we are scraping by for now - another year of too little would kill us off. Prices are too low in my opinion but we have to take on some of those to put bread on the table etc.
What about you? I think you guys more or less missed the world recession didn't you?
Life goes on......
Cheers,
Paul
James,
There is a contract that we have just hopefully won and our main competitor was using a scanning vehicle quoting he can achieve 6mm tolerances with it. I just can't figure how he can quote that.
We say we can use RTK with 5 or 7 epoch readings - rather than 1 shot rapid collection I would use on ordinary topo - and get around +/- 10/12mm or half an inch given that there is control already set every 500m or so and we won't be trying to get data 3 or 4km's away. That's about 0.04' and this guy was saying 0.02' with mobile laser mapping.
I just want to know what I am competing against and is that really achievable? I can understand relative accuracy would be that good, but an absolute accuracy that tight driving along makes my head spin a bit.
I have found figures from 20-50mm quoted online but I want to see if anyone really knows from experience to see what it really is.
Cheers,
Paul
Paul,
I've lost your email. DRop me a line and I'll get you in touch with Cathy Dedecker.
Steve.Kersey.PLS@gmail.com
Steve
With RTK and a cutting-edge INS package, some of these half-million dollar vehicles can get mind-boggling accuracy in the several centimeter range. I'm currently working as an Expert for one of a couple of firms that do this sort of thing in a Patent dispute. Aerial platforms aren't that good.
Big bucks, indeed.
I've seen a mobile scanner achieve roughly +/-0.04' (+/- 12mmm). 6mm? Maybe some percentage of the points, but 95%. Still, these things are pretty amazing.
