Bad Shot

Scott Harmon

Scott Harmon

New Member
Hello all, I am new here, so keep that in mind.

We used the LS today to locate property corners, and stake out points, we had previously been in the field on this job and located additional points with the LS.

We staked out a property corner, set it and then located it, when I returned to the office it was off 6' East and 1.5' South.

This happened to us on a previous job, and we caught it (the location symbol was off and that was odd, so we shot it a second time, and found it was off).

When we are doing stakeout, it will turn green and proceed with only 2 engines fixed.I The confidence level is at a 7, this never happened until we updated, so something changed, we have been using it for 7 months and never had this issue.
 
Adam

Adam

Well-Known Member
5PLS
Scott Harmon said:
Hello all, I am new here, so keep that in mind.

We used the LS today to locate property corners, and stake out points, we had previously been in the field on this job and located additional points with the LS.

We staked out a property corner, set it and then located it, when I returned to the office it was off 6' East and 1.5' South.

This happened to us on a previous job, and we caught it (the location symbol was off and that was odd, so we shot it a second time, and found it was off).

When we are doing stakeout, it will turn green and proceed with only 2 engines fixed.I The confidence level is at a 7, this never happened until we updated, so something changed, we have been using it for 7 months and never had this issue.
Click to expand...


Are you using verify and validate? These are critical to detecting bad fixes.
 
Scott Harmon

Scott Harmon

New Member
Yes, were using both. One other thing I should note. I did not see it with only 2 engines on this shot. This shot was 3 I think, we set the LS on the pin we had just set and the readout was between .01-.03 North and .00-.04 East. Then we located it with 150 epochs
 
Last edited:
Scott Harmon

Scott Harmon

New Member
Minimum RTK engines is set at 1. What should it be set at ? I went into advanced settings and changed it to 3, I went back into that menu and hit default, and it changed it back to a 1.

So if we need to have this at a 3, and a 1 caused the problems, that is the answer.
 
Last edited:
Adam

Adam

Well-Known Member
5PLS
Probably should't use min of 1 engine for critical shots. Were you storing screenshots?
 
Adam

Adam

Well-Known Member
5PLS
I collect 600 epochs with 20 as a confidence level and 10 as a consistency level with 5 groups, min 2 engines and validate with 2 engines, on boundary points. This varies from person to person and I am sure location to location.
 
Nate The Surveyor

Nate The Surveyor

Well-Known Member
What Matt above says is very important. Just "Using the engines" to set corners is not the flow the Javad was designed for.... Except in pure open sky.... BUT even then, I USE the engines to set the corner, then AFTER setting it, set the pole on the set point, press start, and LET IT DO IT's THING. Then, I can do an "Accept As". Or once in a while, I move it a tenth, or 0.12'. BUT, I always do that last shot, storing the point generated by a fully verified shot.
It's "bad medicine" to not press "Start" and let it cook the point good.
I'm learning too.

I am getting a "feel" for how many epochs are necessary. Matt advised me to set it to 600 epochs. With VERIFY. At least 2 engines. in poor environments. This is what I use for boundary work. IF it is light tree cover, or such, I can also drop this back to 90, or 120 epochs. BUT verify is ON, and it verifies with at least 2 engines.
I'm also playing with it, in wide open areas, where I am wasting time.... brushing or other, tasks, and I set it to 2000 epochs. Then set it to cook an extra control point. It take about 7 minutes to do a 2000 epoch shot, in the clear, without interference. Then, I look at the screen, and consider. It's a new tool. Lots of new goodies in there! Be patient with yourself. I often get 2 days of work done, in a day.
Nate
 
Sean Joyce

Sean Joyce

Well-Known Member
I had the same experience. I chased one property corner all over the place. 10's of feet in the woods (glad I talked to Shawn B. after this happened) My procedure for stakeout now is to range it in with as many engines working as possible, get as close as I can, press start and let the L.S. work on the position and fine tune it. (I use a minimum of 3 fixed engines, in my experience 2 engines can give a bad position in a hostile spot) I watch the stakeout residuals until they don't move appreciably and press stop, If not close enough I will adjust and start again. When the position is within tolerance, I will set the point and press start and check it again.
After the final adjustments I collect the point.
In most cases from doing comps and field work etc. we have a pretty good idea where the point should be, an advantage to working on all phases of a survey, as opposed to companies with disconnected field crews blindly performing the stakeout.
 
Adam

Adam

Well-Known Member
5PLS
The LS validate and verify routine is amazing. I think back at the work I did in the past with my other receivers and wonder what might be out there to haunt me. I used to reset and observe twice (with a one engine reciever) and think I was good, The LS has showed me that 2 times aint enough, much less no verification at all. Verify and validate take time, but it's time well spent.
 
Nate The Surveyor

Nate The Surveyor

Well-Known Member
Well, I got a bad one Wednesday. It was a PK nail, (Actually a Mag Hub Nail) in the pavement. I don't remember how long I was on that point, but it was not very long. A car was coming, and I hit STOP, before verify came along. I can look in the LS to see.... it had Duration of 49.4 seconds Sats 7+6 It was not a critical shot, because it was tied with total station before. But, verify is important. I sort of think verify would have caught it, and it for sure would have, with a bit more time. But, you know how it is. Go fast. Get er done. I learned that when my old Legacy E's would lie, was during transition from Poor GPS configuration, to adequate, or from Adequate to poor. I'm still learning this one. But, verify is important.
So, moral of the story is don't turn off verify, or reset RTK manually, and make sure important shots get enough time.
N
 
Matt Johnson

Matt Johnson

Well-Known Member
5PLS
Nate The Surveyor said:
A car was coming, and I hit STOP, before verify came along.
Click to expand...

One thing on our to do list (VSAPP-1848) is to allow users to Resume collecting a point after pressing Stop and before choosing Accept or Reject for situatiation like this. So when a car is coming, you could press Stop, move out of the way, then go back and re-setup on that point and choose Resume to continue collecting the point.
 
Nate The Surveyor

Nate The Surveyor

Well-Known Member
That is a very good idea... Resume! I wish I'd have thought of that! :) So, you press stop. Now, you have options! Save, Resume, or Delete.
N
 
J

Joe Paulin

Well-Known Member
Matt,

I'm glad to see this is on the to do list - many times I have thought it would be nice to have a "pause" button or option while collecting observations in the road and elsewhere. I agree, this will be a great addition to the software.
 
Nate The Surveyor

Nate The Surveyor

Well-Known Member
While we are on this... subject, what about the sequence of WHEN changes take effect?
What if you walk up to a point, that you need a shot on... and plumb the pole, and press START, then you REMEMBER, that the last shot was 2000 epochs, (control point in field, for an extra base site) and you either HAVE to stop the observation, or break the observation into 2 shots.
It would be NICE if you could make changes in settings, (Obviously, some you could not make, such as verify on, or verify off) Because that changes the entire process, of the immediate action. But, to be able to change number of epochs, or the confidence counter, as long is it has not reached the end of the cycle, would be good.
I have done that a number of times. It comes from my philosophy, of "No time wasted". That is set it up, press start, now make changes.
I wonder what is coming, with the "User Presets". Maybe it will allow this. It's the point in time that changes take effect.
Nate
 
You must log in or register to reply here.
Top