I've Regularly Used Up To 10
I am impressed. I am not doing very big projects, nor do I create networks. Just the rural boundary for a conservation or historic project to use in making use of the state coordinate system.
Two would be enough for me to establish a base line if I can get the money for a second.
However, I am curious about what type of project would use 10 or more receivers. Would you be to establish a city or town coordinate system?
My latest project is a grant proposal for the renovation of a historic building. It was known as Schoolhouse #1 in our town.
Get 2 receivers, or do it 2x for more strength.
I checked my notes from the OPUS class and found a general rule that horizontal accuracy can be in the 1 centimeter to 2 centimeter range.
I've Regularly Used Up To 10, BY MYSELF!!
> However, I am curious about what type of project would use 10 or more receivers. Would you be to establish a city or town coordinate system?
None. Save for someone attempting to create a primary control network over a state the ends in "Dakota", where few CORS exist. Even then the coordination of 10 crews over such a large area is just asking for trouble, especially with synchronized sessions. You will most likely lose money on such a job. Then once the project is finished, you will be left sitting in the office, laying off your eight extra surveyors, and stewing as your 10 receivers all look you right in the eye and laugh.
P.S.
This does not apply to government agencies who scoff at the fool who only owns 10 receivers.
I've Regularly Used Up To 10, BY MYSELF!!
> Even then the coordination of 10 crews over such a large area is just asking for trouble, especially with synchronized sessions. You will most likely lose money on such a job. Then once the project is finished, you will be left sitting in the office, laying off your eight extra surveyors, and stewing as your 10 receivers all look you right in the eye and laugh.
I've done a number of projects like this with as many as 10 receivers, but more often 8 or 9. It's a carefully-choreographed dance, and it does require lots of planning and coordination with all involved. We always had one guy -- me or a consultant I worked with -- who kept up with the others as they moved through the project, carrying a spare setup in case someone was unable to make it to their assigned station on time or ran into equipment trouble. The troubleshooter also downloaded the receivers at the end of the day in a location convenient to the day's work.
I always made money on those jobs, and they were a lot of fun. We used public agency staff to man -- and sometimes to supply -- the receivers, so no layoffs were required.
Get 2 receivers, or do it 2x for more strength.
> I checked my notes from the OPUS class and found a general rule that horizontal accuracy can be in the 1 centimeter to 2 centimeter range.
No disrespect not my, I use OPUS often and it's a great tool to keep in your tool box. I attended an OPUS Projects seminar last year and that is incredible, but I do not have the equipment to utilize it. They all give that 1-3 cm stated accuracy, but the vertical does get real iffy unless you can live with 7-9 cm.
Just remember that NGS invented all this GPS gizmo stuff and they are the ones "reporting" said accuracy, and are thus checking their own work on which we rely upon. We have the responsibility to our clients to assure that OUR work meets standards, so we check and verify against them. You are the one signing your name on it and then assume all liability totally regardless of what your OPUS printout says.
Get 2 receivers, or do it 2x for more strength.
The Department of Defense invented the Global Positioning System not NGS.
Get 2 receivers, or do it 2x for more strength.
True story Batman, but did Dr Geico know that they invented it to blow up buildings with missiles, not obtain cm accuracy, or even meter accuracy. Boom, you're dead. Some pretty smart private companies perfected it once they turned off.... come on Wayne, what's that secret word from back in the old days when you had limited usage and not 24/7.... brain phart here.
NGS is now the "administrator", and pretty good IMO. No different than your local county flood control department being the administrator of anything FEMA says. Or the county/city engineer meeting state & Fed DOT specs for funding. Or us surveyors meeting state regulations, which are administered by the BTR. It's a bigger picture than you know and we all live it.
I've said it before and I'll say it now - I liked the world better when it was flat. Did you ever calibrate your 4 ft hand level when you're building a shed or a deck? Didn't think so.
I've Regularly Used Up To 10, BY MYSELF!!
You only have 9 receivers?
I scoff at that LOL. 😉
We have 5 currently. The other crew has 2 Topcon GR3s which can do static or RTK base and rover. My crew has 3 Trimble R4-3s which can do FastStatic or one RTK base and two rovers. Sometimes we do RTK base (stores a file), one FastStatic and one RTK rover.
This week we are building a network of triangles, long sessions, FastStatic.
I've Regularly Used Up To 10, BY MYSELF!!
> You only have 9 receivers?
My current inventory comprises 9 Trimbles, 2 Topcons (the Trimble variant), and 2 Javads, plus 3 L1-only Ashtechs. It's a pretty motley group, but it gets the job done.
Suggestion:
RENT 3 receivers from a local surveyor, and let him post process it for you, and opus it for you.
You can rent some from somebody.
N
Four is best for control work
Get 2 receivers, or do it 2x for more strength.
You are thinking of Selective Availability. When your position was instantaneously spoofed in a random direction up to 300 meters. The lack of full time satellite coverage was simply due to the fact that a full constellation had yet to be launched.
Selective Availability (SA) was turned off because citizen use was hampered. However when it was in use the process to obtain accuracy was more complicated but not impossible. Using four receivers simultaneously with two on published coordinates and two to establish coordinates (rovers) one could calculate the shift in position due to SA. Then centimeter accuracy was able to be achieved.
Achieving accuracy still depends on proper procedure like any other surveying activity.
What Type Of Project Would Require 10 Receivers
Setting control for a 100 acre farm with woods and hills. With long static it is sometimes not necessary to traverse the whole project. Some were surveyed in 2 sections some in 3. On others it is easier to start out from control points and survey to the next section. I.e. with control out there already the traverse methods can be less than ideal. Some traverse were merely a check.
One 13 GPS setup project was to tie surveys of 7 different owners together. Started out with 5 acre survey and grew as the neighbors joined in. Last 2 were 20 and 24 acre parcels. Survey area was 80% woods. Would tie in some front yard road frontage and survey into the woods. A lot of the area was never successfully farmed, so little occupation to follow. Several areas had L shaped rock rows with no field ever established. Land was most likely bought sight unseen in the late 1700's and the owner/farmers most likely failed. Two sets of GPS were to tie in the few abutting rear subdivision monuments along my surveys to subdivision frontage monuments farther away than I wanted to survey. Overall there were 4 GPS days over a 2 year period.
Paul in PA
What Type Of Project Would Require 10 Receivers
We currently have 8 duel freq receivers. And we use them on Section breaks all of the time. I like to set up 2 on local 'base stations', that I have or will have collected 2-3 days of data on, and then the other 6 get roved around to section corners, and frequently are set out in inter-visible pairs or triplets to tie in additional info, or in areas where I know we will be setting a corner later.
I plan on one more pair this spring (only because I want new RTK), and will likely hold at the 10 count. All of my stuff is Topcon or Javad.
What Type Of Project Would Require 10 Receivers
Here's one on which we ran 10 receivers:
