Post pics of difficult shots

K Davis

Member
Went back today to get more shots around the base of a cliff. I took shots 360, 361 and 362 which were about 5 feet away from a Forest Service corner on the side of a large rock near the base of the cliff. I'm pretty sure I had a verified fixed RTK shot on 360. I then started 361 and took a screenshot during the shot, which I don't usually do. I don't think 361 verified but it was very close to 360. I did not get verification on 362 but stored for PPK. After DPOS, the shots are all over the place. This shot was at the base of the cliff about 10 feet away. Obviously a multipath environment with the cliff on the west side of the shot. I haven't ever had 2 consecutive shots so close with apparent fixes solve so far apart after DPOS.View attachment 8512
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Matthew D. Sibole

Well-Known Member
5PLS
I would hold the RTK shots for 360 and 361. I would like to see the screen shot for 360 to see how much time was on that shot but you do have two that agree.
 

K Davis

Member
I think 360 is good and thought 361 was good but it is 10 feet to the northeast from 360 after DPOS.

Going back tomorrow and just let it cook while I do some other stuff. With more time I'll get a good coordinate.
 

Matthew D. Sibole

Well-Known Member
5PLS
DPOS solutions are nice but they are not always correct. That is why we have the ability to switch from the DPOS solution back to the RTK solution. We give the surveyor the ability to make the final decision.
 

Duane Frymire

Active Member
Went back today to get more shots around the base of a cliff. I took shots 360, 361 and 362 which were about 5 feet away from a Forest Service corner on the side of a large rock near the base of the cliff. I'm pretty sure I had a verified fixed RTK shot on 360. I then started 361 and took a screenshot during the shot, which I don't usually do. I don't think 361 verified but it was very close to 360. I did not get verification on 362 but stored for PPK. After DPOS, the shots are all over the place. This shot was at the base of the cliff about 10 feet away. Obviously a multipath environment with the cliff on the west side of the shot. I haven't ever had 2 consecutive shots so close with apparent fixes solve so far apart after DPOS.View attachment 8512View attachment 8516View attachment 8517View attachment 8518View attachment 8519
Looks like you didn't save the rtk shot that screen shows about 0.03 from previous shot 360, because I don't see confidence or consistency values in the table above. I always save the rtk even if it doesn't go through the final verification stage. Many times it will still be better than ppk solution, as evidenced by agreement with your shot 360 (if in fact that went through all stages). But I agree, I would shoot it again in this instance.
 

K Davis

Member
DPOS solutions are nice but they are not always correct. That is why we have the ability to switch from the DPOS solution back to the RTK solution. We give the surveyor the ability to make the final decision.
I was thinking about that but I'm not sure how to do it. Since I am still working in that area and it's easy to get to I will shoot it again anyway though.
 

Duane Frymire

Active Member
I was thinking about that but I'm not sure how to do it. Since I am still working in that area and it's easy to get to I will shoot it again anyway though.
If you're on a point for a long time and rtk will not go through final verification just hit stop, then accept (instead of pp options). Then in your points screen you will have choice of either solution after dpos.
 

Matthew D. Sibole

Well-Known Member
5PLS
On the points screen there is a little button at the top right that looks like a graph. Highlight point number 361 and hit the graph button. You will see the PPK results and the RTK results. You can select which ever you feel is the better solution.
 

Duane Frymire

Active Member
Not sure this was on my bucket list, but last minute got talked into driving in a Saint Patrick parade. Protest float asking for public restrooms in small tourist village of Old Forge, NY. In return they gave me advertising on the truck and I had the T2 mounted.
It was a crowd favorite and float got second place.
Did I mention it's a very small village?:)
 

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K Davis

Member
I went back today and confirmed that point 362 in my earlier post was the good shot. I got one good verified RTK shot (370) and 2 PPK's that all clustered within about .10 with point 362. I also took a shot 3.55 feet away by tape measure as a check but that was farther from the corner I was tying into. This shot processed 3.50' away as a PPK.

And I got the RTK shot 370 at the 1HZ rate. I didn't read the update thread saying that the upsampling rate would reset to 1HZ and turn upsampling off. So I updated last night and when I got to the field today could not remember how to set it back to 0.2 and upsampling. But all's well that ends well!

Also, Matt, I didn't realize you could switch back on that screen to the RTK, so thanks for that. After doing that to points 360 and 361 they also fell within the cluster. This is a rural survey per KY standards so I feel my results meet the standards. And lastly, my base was in a good place, on the cliff above me 325 feet away with full view to the horizon except to the NW, so that helped.

Bottom line, the JAVAD system performed superbly on this shot!




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Sdrake14

Active Member
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I have been foolin' around with this idea here and there for a time but this shot seemed to be definitely an effect I suspected. On this iron using RTN no fix, no way, until I put my hat in position shown...then bam the RTK started collecting and saved verified. Now maybe superstition but I thought "hard surface more parralel bounce, add felt filter it"....? I had some past similar experiences.
 

Nate The Surveyor

Well-Known Member
Now, I don't know why it would not rtk... But sometimes, I've seen it get better radio link, by rotating the LS, and sometimes my hand can affect radio reception. (Magnetic maybe?)
It can change the local radio signal bounce, and help/hurt, if that's the case...
N
 

Aaron S

Active Member
How long would it have taken to traverse that 1605' from the last shot?
This particular corner is only about 100' from the edge a big clearcut - you could darn near do it in one setup. However, if you had done it before the logging in that area (with the forest at full strength)... a traverse would have taken the better part of a day I'm guessing.
 
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