I've done a number of large projects using public agency staff as receiver operators.?ÿ We always do a couple of hours of classroom training followed by a couple of hours of hands-on setup and operation training.?ÿ Almost all of these staffers were smart, conscientious and dedicated enough to get the job done well, but one time we had someone whose don't-give-a-damn attitude caused trouble.?ÿ ?ÿAt one site he ignored the to-reach description and instead of setting up on the designated mark that was out in the wide open, he found another monument (set by a different agency and of totally different character) off in the weeds and occupied on that.?ÿ A couple of other times he missed his turn-on times or failed to show up at his designated mark entirely.?ÿ After a few days we asked his supervisor to assign him to other work, and I learned later that he got fired for doing the same kind of thing in his regular duties.
Late last year we were doing a road topo in the CBD, all was good. On the last day late in the afternoon we'd finished so I suggested we shoot another tie into a Govt mark, and to the rodman described its position, 126m away in the middle of the footpath. Off he went, and while he was on the search I took the time to get some more reflectorless shots and fettle with the TS. After about 15 mins, I hadn't heard anything from him on the radio, so I turned around and there he was, 100m away, prone on the footpath in rush-hour pedestrian traffic, dusting it with his handkerchief. I think if he'd had a microscope, he would have been using that as well. His reply to the question about whether he'd found it, was a muffled "not yet". I gave it another couple of minutes then pulled the pin on the operation. A couple of days later in the office I found out that I'd got the coordinates wrong and that mark didn't exist in our survey area.
I'm really not for, or against any particular solution... Except to say it's a situation that demands an answer, and we all will pick something as a solution.
I once came by another (freshly licenced) surveyors base station. So, I wrote on the back of my business card "thanks, but I have my own gps system". It was about 8' from my GPS station. Later, while working off my base, (painted x in stone) I looked for his nail. He'd set it in the track where delivery trucks turned around. It was a 30d, bent about 45 degrees. So, it was disturbed. I consider the base to be the single best control station on a given job.
N
Were all going to face GPS base pincushions. It's really a matter of how we face them. Another thing is ALWAYS have a second point, that you can 2x check on.
I know a surveyor who rarely set a base nail... He'd RE localize every trip to the area. He always ran on "true north" ground scale. If he set his base typically within 100' of his same location, and did a one point localize, it worked.
Anyhow, I'm working out ideas to make the "GPS base pincushion"problem safe.
Another trick is to set a new xbase nail, somewhere near your base, for an easy double check. I started doing this several yrs ago, when I found a piece of equipment parked on my base.
I can see F.) Being set your own base nail/monument, and tear out the rest. This is what I think would be playing dirty.
I can also see ordering some caps stamped CONTROL/ PLS#XXXX. Or GPS/Ctrl
Pls#xXxX?ÿ
With all of them a rebar.?ÿ
So far, I've been usually using an elec. Drill to make a good dimple in rr spikes. Or, using a chop saw to carve an x or + in top of rr spk. And, always setting xbase somewhere. Sometimes multiple xbase points. (Xbase is PT desc for extra base point) they are always an inch or 3 below the surface.?ÿ
Anyhow, thanks for reading my thread. And the good ideas/feedback.
N
Please explain why the location of your base is superior future data compared to equally sturdy monuments of your survey.?ÿ Checking two or three others should get you back to where you were for doing future work.?ÿ You should be checking that same number of other monuments anyway.
?ÿ
Hooly cow,
Mine is superior:
because it's buried deeper
Because it's got rocks and gravel pounded around it, to stabilize it.
The ones I'm finding, are way too often on the surface, or even protruding above the surface, such that they are unstable. Frost will move them. They are easy, and handy, but not long lasting.
I dig holes, pound the ground, and pound gravel into the dirt, most of the time. I sometimes do other things, to make them more useful. Paint on top, pound them through a flattened coke can, or other local trash. The TROUBLE with my system is it's prone to not be noticed, by another surveyor, and they might set their own.
I'm not bringing this up, because I'm totally satisfied with my own solutions.
I do try to make an xbase on every visit to that job.
N
?ÿ
Nate,?ÿ
You can always use OPUS SHARE...
https://www.ngs.noaa.gov/OPUS/getDatasheet.jsp?PID=BBFT48&ts=17297094353
Nate,?ÿ
You can always use OPUS SHARE...
https://www.ngs.noaa.gov/OPUS/getDatasheet.jsp?PID=BBFT48&ts=17297094353
I question whether a nail meets the intention NGS had for OPUS SHARE. Definitely could be useful for a more substantial monument.
Now, how do we get everybody into the habit of checking that list?
To ddsm,
Thank you for sharing that. There is a lot to learn for some of us. I'd like it if such thing were semi automated. I'm not super good at putting that together. Maybe a 2nd generation will include ways for DPOS to do that.?ÿ
I guess that getting all the surveyors "on the same page" is good, but it requires that some of us smarten up... And that's the rub!
Nate
To ddsm,
Thank you for sharing that. There is a lot to learn for some of us. I'd like it if such thing were semi automated. I'm not super good at putting that together.
It isn't hard. You collect at least 4 hours of static L1+L2 GPS data (other constellations ignored) on the point. Carefully record the ARP height. Take close up and area picture and some reference ties.
Get the file in a suitable format for OPUS (RINEX or some vendor raw formats). Go to the NGS OPUS website. Enter the file name, antenna type, ARP height, and email address. Check the share box. Submit.
The next page comes up for you to supply the description and pictures. See DDSM's example for how to word it. You enter the NGS PID if on a mark already in their data base or else give a new one a name.
Afterward you get an email of the preliminary data sheet to approve or edit.
Bill,
Back in the GPS on Benchmarks program it was a regular 'get together' for Arkansas Surveyors...4 hour OPUS observations in the mornings and 4 hours of storytelling and beer in the afternoon.
DDSM
