What on my screen would tell me 70 was a bad shot in field?

John Troelstrup

Active Member
This happens occasionally and I would like to know if it is to be expected or if there is something on my screen to keep an eye on or perhaps a white box that I do not have active and should.
Point 70 is the bad shot. I was shooting a sidewalk and the distance in the field between 69 and 70 was only 5 feet in the field and basically flat vertically. Both shots seemed normal and verified normally. I did not notice that 70 was a bad shot until I got back to the office and began drafting.

The only clue I see is the white box that I circled which is the difference from the last point verified.
If paying attention, I would have known that I only moved 5 feet and not 14 feet and that the vertical did not change 10 feet.

Advice. How do you know a shot is good before walking away even though it has been verified?
 

Attachments

  • BadShotQuestion.pdf
    258.2 KB · Views: 273

John Troelstrup

Active Member
Sent.
It is Titled 3334 Anna George.
Thank you for looking into it.
I know I am a lot of updates behind and I hope that is truly is not a factor.

I am very hesitant to make the new version upgrades as there are some fundamental changes in the menu structure and it has been quite buggy.
I am not the most savvy person in regards to GPS and my current field production does not allow for down time to figure out new methodology.

A motto of mine has always been, if it aint broke...dont fix it.

My main question remains, was there a clue that I missed, besides the red cloud box, that the verified shot was bad?

Thank you for your time.
It is appreciated.
 

Adam

Well-Known Member
5PLS
This happens occasionally and I would like to know if it is to be expected or if there is something on my screen to keep an eye on or perhaps a white box that I do not have active and should.
Point 70 is the bad shot. I was shooting a sidewalk and the distance in the field between 69 and 70 was only 5 feet in the field and basically flat vertically. Both shots seemed normal and verified normally. I did not notice that 70 was a bad shot until I got back to the office and began drafting.

The only clue I see is the white box that I circled which is the difference from the last point verified.
If paying attention, I would have known that I only moved 5 feet and not 14 feet and that the vertical did not change 10 feet.

Advice. How do you know a shot is good before walking away even though it has been verified?
Is this on an rtn with GPS and GlO only? Looks like your using the 2 engine multi rtk firmware (maybe not, i just notice 2/2:2 up there). 2 engines with major differences in signals used is a really condfident solution. Not so much when its only GPS AND GLO. The DTL white box is the best way to verify a quick shot.
 

John Troelstrup

Active Member
Is this on an rtn with GPS and GlO only? Looks like your using the 2 engine multi rtk firmware (maybe not, i just notice 2/2:2 up there). 2 engines with major differences in signals used is a really condfident solution. Not so much when its only GPS AND GLO. The DTL white box is the best way to verify a quick shot.
Thank you for the reply Adam.
I never use the RTN. I always use my T-1M base and DPOS upon return to the office.
Yes, 2 engine. I have not pursued the updates that offer multi-engine RTPK solutions yet.
The process baffles me still and seems to have been buggy when first introduced.

I will be staring at the distance to last box more often now...just making sure I was not missing an obvious flag to a verified shot.
 

Bill Eggers

Active Member
Good question, those screen shots look like good results to me.
DTL could have saved you on this one, but how would you know if it was off this much when the next shot was 300' away?
 

Shawn Billings

Shawn Billings
5PLS
Are you using 4 constellations or only GPS and Glonass?

Are you sure you are using the 2-engine firmware or do you mean you have 2 engines set for minimum RTK engines (as the screen captures show). These are two different things.

Verification with GPS and Glonass only:
If you are using GPS and Glonass only, your screen capture does not prove that 70 (or 69 for that matter) are good. You only have 18 seconds of observation time. For the existing verification method to work, you need 180 seconds between fixes. This is why the Boundary profile uses validation after 180 seconds. Some of our PLS team insist on 240 seconds, which is even better. The time allows for the constellation to change ever so slightly which changes how the signals are affected by multi-path. If you get a fix now and then can repeat that fix in 180 or more seconds, then the likelihood is that the fix is good.

Verification with GPS + Glonass + Galileo + Beidou
With multi-constellation it appears that we have enough satellites to use some in one engine and some in another which gives enough variation that we don't need to wait for 180 (or more) seconds for the constellation to change. If engine 1 and engine 2 agree, then the likelihood is that the solution is correct. But I cannot stress this enough - this is only true with multi-constellation data (base and rover) and engines configured differently from each other.

It looks like your pdf shows that only GPS and Glonass were used in the solution and that you only had 18 seconds, which means the conditions for verification (minimum 180 seconds between fixes) were not satisfied.
 

John Troelstrup

Active Member
Shawn,

I have not performed any of the last major updates so I am running the old school setup.
Also using only GPS and Glosnass.
I am waiting for the bugs to get worked out and simplified profiles to be established before getting major upgrade.

I used the Precise Topo verification setup. Sometimes it verifies in 18 seconds and sometimes it takes a bit longer.
Is that setup not adequate for the incidental shots like sidewalks, driveways, fences, utilities etc?

Always open to suggestions,





Are you using 4 constellations or only GPS and Glonass?

Are you sure you are using the 2-engine firmware or do you mean you have 2 engines set for minimum RTK engines (as the screen captures show). These are two different things.

Verification with GPS and Glonass only:
If you are using GPS and Glonass only, your screen capture does not prove that 70 (or 69 for that matter) are good. You only have 18 seconds of observation time. For the existing verification method to work, you need 180 seconds between fixes. This is why the Boundary profile uses validation after 180 seconds. Some of our PLS team insist on 240 seconds, which is even better. The time allows for the constellation to change ever so slightly which changes how the signals are affected by multi-path. If you get a fix now and then can repeat that fix in 180 or more seconds, then the likelihood is that the fix is good.

Verification with GPS + Glonass + Galileo + Beidou
With multi-constellation it appears that we have enough satellites to use some in one engine and some in another which gives enough variation that we don't need to wait for 180 (or more) seconds for the constellation to change. If engine 1 and engine 2 agree, then the likelihood is that the solution is correct. But I cannot stress this enough - this is only true with multi-constellation data (base and rover) and engines configured differently from each other.

It looks like your pdf shows that only GPS and Glonass were used in the solution and that you only had 18 seconds, which means the conditions for verification (minimum 180 seconds between fixes) were not satisfied.
 

Adam

Well-Known Member
5PLS
Shawn,

I have not performed any of the last major updates so I am running the old school setup.
Also using only GPS and Glosnass.
I am waiting for the bugs to get worked out and simplified profiles to be established before getting major upgrade.

I used the Precise Topo verification setup. Sometimes it verifies in 18 seconds and sometimes it takes a bit longer.
Is that setup not adequate for the incidental shots like sidewalks, driveways, fences, utilities etc?

Always open to suggestions,
No the profile is not good enough. For GPS and glo only the only way to know if it is good is time speration between fixes that agree or to verify bit yourself with the distance to last. You are correct Bill once you get separated further than you can judge dtl isn't useful.
 

Adam

Well-Known Member
5PLS
I'm still not clear, are you using the 2 engine firmware or the standard 6 engine firmware?
 

John Troelstrup

Active Member
Adam,
I am using the Triumph, as it came to me a couple of years ago.
I have not installed any of the updates that go along with the multi-engine, RTPK etc that have occurred over the last year or so.
I do not have the mental comfort to deal with downtime and tweaks.
Waiting until the waters settle and solid profiles are established.
I am not knowledgeable enough to be pushing a lot of buttons to seek a solution.


To follow up though...
So if you are detailing a parking lot for example, after the Boundary portion is complete with proper and timely location times.
When it comes time for the linework and miscl shots such as EP, Inlets, Hydrants, light poles parking spaces, building corners etc....

You take two minute or longer observations for each shot?

No the profile is not good enough. For GPS and glo only the only way to know if it is good is time speration between fixes that agree or to verify bit yourself with the distance to last. You are correct Bill once you get separated further than you can judge dtl isn't useful.
 

Shawn Billings

Shawn Billings
5PLS
If necessary yes. The physics don't care if you are locating a boundary corner or edge of concrete. Distance to last can help you take more responsibility for determining if the fix is good in some circumstances.

The latest updates make a huge difference in how we're locating points. It's much faster using new rules. These new rules are being added to the software to make them easier to use.
 

Shawn Billings

Shawn Billings
5PLS
The site conditions at a given point determines how you need to locate the point much more than what the point is. If the point is under canopy or near obstructions you'll need to use a profile that requires more time separation between fixes such as the boundary profile. If you are near light canopy or few obstructions then a profile that requires less time is fine.
 

Nate The Surveyor

Well-Known Member
(Qualified answer) I'm using t-2, and 6 engine software, 2 constellation.
I often use boundary profile, for wide open shots. No obstructions. Let it run for 5-10 seconds.
A few obstructions, 15-30 seconds, with a reset rtk.
Worse obstructions, 45-90 seconds, with 3 resets of rtk.
And, pretty bad obstructions, 90-120 seconds, with 4 resets.
From there, it's a full boundary 200 seconds, with verify.
This is a 2-way variable. If sats are in good geometry, less time. If LS is going slow, then more time for confidence. (That's backward to what I'd like) but, I hate a bad shot.
Nate
 
Top