Bad Field Day... Need help if possible

:unamused:
I flew 105 acres today.
My M300 was flying at full ability, as the wind was 12m/s at 60m AGL!!
We did get the whole survey.

Everything was super awesome until I got home. The gps base station file got deleted by accident (its gone and its mostly my fault) and I am unable to recover it. I am very stomach sick…

So I processed my data using “RTK”. Why not, right?

This is what I got… two layers/surfaces!!

I believe I am seeing this because I had no PPK corrections to fix this?
How can I fix this with RTK, or is that even possible?

I am going to have to re-fly :disappointed: anyways… but if there is a way to fix this, I’m interested!

Ref. Lidar job#4076.

Sorry to hear that @FlyingRadioWaves. Is there a CORS base station nearby? Checkout How to get CORS base station RINEX data

RTK isn’t going to help you as it is simply used for data capture verification in the field. Without trajectory correction you will end up with vertical separations and data inconsistencies across the board. You really need a RINEX source.

Best case of course is going to be to re-fly…

I was able to access our “CORS” station raw data. I ordered the recording for the time period I needed. I took the CORS data and processed it. The resulting data set is as you described… vertical separations and inconsistencies.

But why would I get that if I processed my data with PPK using the CORS?

I re-flew the mission, but I still want to know. I have a feeling this won’t be the last time we loose base station data in the field.

How far away was the base station from your AOI?

When you processed it in PCMaster did it give you lever arm values?

If it is too far away then it simply will not be able to do the lever arm and that’s likely what causes your vertical separations.

Thank you for this…
I did download the “CORS” data from the “base”, which was approx. 38.5km away.
I checked my processing report from the “bad data” against the known “good data”.

The CORS base was simply too far away. I can see that the software could not really resolve the lever arm and my IMU-GPS misclosure was in METERS!!

I looked at the quality of the GNSS position data received from Can-net, and it is all over! What’s the oldest saying in our line of work??? Garbage in, garbage out?


The left is what I received as CORS data. The right is from my base station (when I re-flew it).

Was that CORS data 1s intervals?

Noticeable difference there eh!

It WAS in one second intervals.
But… I realize an error I’ve made and I since reprocessed the data and it looks better now.

What did I do wrong?

  • When asked for the “base station” Lat/Long, I entered MY location, not that of the actual, physical base station.
  • Data is no longer separated by the elevation difference between passes!

I’m going to run this data into the Rock Cloud to see what differences I get between CORS and local base station.
While I have a complete and nicer data set from the CORS, the error in the report is still quite large compared to the local base station set up.