Zenmuse L1 GCP or PPK workflow

Hey all,

new to LiDAR mapping as we’ve recently bought an L1 as an entry into LiDAR. I have a few questions that I could not yet get answered otherwise on the internet. I’d appreciate some input from you please.

  1. Can the L1 data be processed using only GCP’s? Also - very few possibilities to have the drone in RTK over NTRIP as we have a very limited network. So I’m not meaning GCP’s and RTK on drone. Pure, GCP’s on the ground.

  2. Or does one have to have a base station logging in order to PPK the data and orient the pointcloud?

  3. If using RTK over NTRIP on the drone, is it then necessary to have a base station logging also (for PPK)?

  4. Is it recommended to set up a base station to log data for PPK (Emlid Reach RS+ or RS2) and also connect the drone to that same base station for RTK at the same time, or would you rather have the base log its files separate and either fly the drone in regular GPS mode or RTK over NTRIP and then PPK the data from the base and drone?

  5. Final question for now, we have a request to map a 10km road, 40m wide with LiDAR. What kind of GCP spacing/setup would you recommend for this?
    My only reference with corridor mapping comes from photogrammetry and I know the model can be prone to warping, which likely necessitates more GCP’s. But I haven’t done this with LiDAR as yet so how do I go about with mapping this with LiDAR? I don’t know whether this data might also be prone to warping?

Thanks for helping out and I look forward to learning a lot from this community!

You must have a base station logging correction data from the gnss.

The drone has gps, which is equivalent to my handheld Garmin… sure, you could have correction data going to the drone, but who cares? It still needs to be corrected against a known point/signal.

GCPs are useful to calibrate and truth your data. The more you have, the better you can qa/qc your data. Too many is just as poor as not enough.

10km road… I would have 10 gcps and some ground shots to confirm my x,y,z.
Good mission planning here is a must. Have at least 100m overlap between legs. Depending on your location and appetite for risk, you could the entire 10km from 2 setups?

Rock Lidar data does not warp. I doubt the L1 would, but I have no experience with the L1.

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