Trajectories and an ATV

[John Thompson]

I collected some trajectories with my ATV on Friday. Wide open skies. I had these settings selected:

I meant to set Traveled Distance to 25 feet, and didn't notice it was 250. The points were dense enough though because Horizontal Off-Line was set to 2. I think I normally use 5 or 10, but it was set to 2 and I left it. In many places the trajectories look like this:

The zigs are about 2.5 feet long. Total length shown here is 77 feet.

What caused these zigs? Does the LS compensate for tilts while collecting trajectories? I wonder if the roughness of the ground caused an oscillation with the tilt compensator. The ride sure didn't feel that rough. This particular section was pretty flat and smooth.

I generated contours from these points and they look correct.

 

[Michael Stazhkov]

I collected some trajectories with my ATV on Friday. Wide open skies. I had these settings selected:
View attachment 8870

I meant to set Traveled Distance to 25 feet, and didn't notice it was 250. The points were dense enough though because Horizontal Off-Line was set to 2. I think I normally use 5 or 10, but it was set to 2 and I left it. In many places the trajectories look like this:
View attachment 8871
The zigs are about 2.5 feet long. Total length shown here is 77 feet.

What caused these zigs? Does the LS compensate for tilts while collecting trajectories? I wonder if the roughness of the ground caused an oscillation with the tilt compensator. The ride sure didn't feel that rough. This particular section was pretty flat and smooth.

I generated contours from these points and they look correct.

Do you have recorded GNSS file for the trajectory? Could you "Send Project to Support" (button on the Projects screen).

 

[Michael Stazhkov]

Does the LS compensate for tilts while collecting trajectories?

Yes if "Correct for Tilts" is checked.

 

[John Thompson]

Sent to support. SN 229.

 

[Michael Stazhkov]

Sent to support. SN 229.

As I see you have "Correct for Tilts" enabled in your profile. Will investigate GNSS file later.

 

[Michael Stazhkov]

Sent to support. SN 229.

Unfortunately I don't see raw GNSS file recorded with the trajectory. It is better to enable GNSS file recording for all kind of survey.

 

[John Thompson]

OK. Thanks for checking. I have a few more topo maps to make so I'll experiment with it.

 

[John Thompson]

I sent another project to support. (Wauneta-SN229) I made two trajectories over the same area, with and without correcting for tilts. Both had settings like this:

Ignore the first (short) trajectory. The second one had tilt compensator ON and the third had tilt compensator OFF.

With the tilt compensator ON, there are several places where the trajectory stored multiple points in rapid succession, caused (I think) by the tilt compensator. The trajectory with the tilt compensator off looks ok to me.

Points to check:
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[Shawn Billings]

Engine vibration may be problematic for tilt sensors. I would not use tilt compensation on a motorized application.

 

[Adam]

I prefer to have tilts off for trajectories. Your elevation will be off about a tenth at about 10 degree tilt. Thats assuming the ground is flat and you have one side of the atv jacked up. When the ATV is tilting because its on a slope the LS tilts as well and the LS almost always tilts downhill. Because of that the elevation will be even closer to correct. The ground is falling away in the direction of the tilt.