Post pics of difficult shots

Darren Clemons

Well-Known Member
...warning...only Javad users may enter!
We had about 2500' of this creek to locate - a good bit of it right up next to a large cliff.....used 2 LS's and hopscotched each other.
Had about 5 shots that we had to store PPK shots (all five of them we ended up having at least a few epochs of good RTK)
 

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Matthew D. Sibole

Well-Known Member
5PLS
A shot that I expected to just post process. Ended up getting 6 repeated epochs over 600 seconds. I am going to shoot it again to verify the coordinate but I can’t see that being wrong.

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The post processing of this shot did not return any good results. I went back today to reoccupy the pipe. You will notice in the top left white box (Pdelta) that is it 0.38’ off of the post processed point 116. The screen shot above is of the RTK point 116. The RTK shot was 0.78' off of today’s good fixed solution. I reshot today’s point again so I know I had at least two shots that agree with each other. Redundancy is key. If you can’t repeat it the next guy can’t either.

I will have to say that I have never seen an RTK shot that had more than 300 seconds between fixed epochs be bad until this shot. While the 300 second rule is generally a good rule it does not always work and does not absolve you from checking to make sure it is a repeatable result!

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A shot that I expected to just post process. Ended up getting 6 repeated epochs over 600 seconds. I am going to shoot it again to verify the coordinate but I can’t see that being wrong.

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I believe it Matthew! I have successfully collected 100's of shots just so with the LS. My skeptics still hound me. Just last night at the CLSA meeting I had unbelievers inquiring "can it really get a fix in canopy?". Sorry TLT....."can't touch this.....hammer time".
 
A shot that I expected to just post process. Ended up getting 6 repeated epochs over 600 seconds. I am going to shoot it again to verify the coordinate but I can’t see that being wrong.

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I will be curious to see how well the reshoot compares. I am still trying to get a good feel for what is going to be good based upon field data. I would hope with enough time on point that something like this could be resolved with post process. Considering that it's a float solution and all the numbers on screen look pretty rough to me. But I have been surprised and mystified at the results we do get many times.
 

Matthew D. Sibole

Well-Known Member
5PLS
That is not a float solution. That is definitely fixed. All of the dots on the screen are “fixed” solutions. It is a matter of know how to read the screen to know when you have enough time and which fix is the right one.

In the screen shot above you see the number at the front of the list 6,602,5. When I hit stop that is the group of fixed epochs that I am accepting to be the right one. That is 6 epochs that agree within 0.13 horizontally and 0.23 vertically over the course of 602 seconds. All of the other numbers and dots on the screen represent a fixed epoch and time but which ever “group” of fixes that has the most amount of time on it will be the one the program chooses as the best.

The whit box at the top left is PDelta and is the calculated corner based on the deeds and the middle right white box is the distance to last. It is supposed to be 60’. I know it is close and will post my verification data later once I have had time to review it all.
 
"distance to last" assigned to a white button has been one of my favorite features for analyzing the quality of my measurements on the spot. On a shot like this once it is stored I can easily see, on the spot, if the system is giving me consistent repeatable measurement. If I have questions on the spot I can continue to take multiple shots on the position until I am comfortable...even if it is leaving with multiple statics to process. When I have just hiked "up" and hour-and-half for a shot is is reassuring knowing I am probably done there, without a need to return.

And on a remote shot I always try for multiple RTK's just for sanity, and the "DTL" still shows a reassuring real-time quality in the measurement.

And there is always the great redneck check of 2 nails out of pocket a few feet away and a two-tape tie to verify.....this has also been a method that has given me confidence in the LS. Other old-time methods like ranging from pickets in conjunction with a cantankerous shot can aid in the weeds too...
 
...warning...only Javad users may enter!
We had about 2500' of this creek to locate - a good bit of it right up next to a large cliff.....used 2 LS's and hopscotched each other.
Had about 5 shots that we had to store PPK shots (all five of them we ended up having at least a few epochs of good RTK)
Darren you were spot on when you mentioned our environments look alike....
 
"...warning...only Javad users may enter! "


After using this equipment for 3.5 years I continue to be impressed.
Here is a good example of the advantage of mission planning and being there at the right time.
I never thought I would be able to SET an iron in this hemlock woods in a creek valley.
When I navigated to my search point for this corner I didn't even come close to getting a fix.
I set the first 2 corners in open areas the second one in the foreground of the first picture.
From my mission planning view I saw I was there at the optimal time and decided what the hell I'll give it a try.
Really pleased with the results.:)
 

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"...warning...only Javad users may enter! "


After using this equipment for 3.5 years I continue to be impressed.
Here is a good example of the advantage of mission planning and being there at the right time.
I never thought I would be able to SET an iron in this hemlock woods in a creek valley.
When I navigated to my search point for this corner I didn't even come close to getting a fix.
I set the first 2 corners in open areas the second one in the foreground of the first picture.
From my mission planning view I saw I was there at the optimal time and decided what the hell I'll give it a try.
Really pleased with the results.:)
The dreaded midafternoon doldrums in the NE.
 

Aaron S

Active Member
A shot that I expected to just post process. Ended up getting 6 repeated epochs over 600 seconds. I am going to shoot it again to verify the coordinate but I can’t see that being wrong.

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It looks like the second group is very similar statistically to the first one. These first two groups on the N/E plot are right on top of each other - maybe a couple tenths apart? Based just on that screen, it seems they are too close to call. What did you use to pick one over the other? Post processed shot, or something else?
 
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This was some old city woods near Westerly Hills on the west side of Charlotte, NC. Must have seen better days since I hear gunshots in the background...
Skeeters so bad in this old ditch that I hiked this in here in the morning...cut a circle around it and let it cook...left it while doing TS work. Two hours later I stored it and repeated.

Got two observations that agreed within 0.03’...I’ll take it!!!

Summer in Carolina, gotta love it!