RS2 with mavick 3 Enterprise rtk

Hello Everyone

I need some help with something that is probably easier than I am making it. I have an RS2 and a Mavic 3 enterprise. I have the RTK networks set up and the drone is flying with no problem using drone deploy. In my past life, I was a survey party chief and I am used to Trimble, Carleson, and Topcon Software. It has been eight years so I am sure I am missing something easy.

the short version is that I am getting lat long ellipsoid height in base mode but I want it to kick out northing easting and ortho elevation. please read below for the entire story.

My confusion is that when I switch base corrections on and get everything hooked up and it all flies well but the coordinates I see come up for the base location give me lat long and ellipsoid height. All of my jobs are working in state plane (NAD83 and NAVD88 geoid 18). I was hoping I would get my base location on the same datum so I can easily glance at it and know it’s close. I am also worried that the photos for the drone will be tagged at ellipsoid height so I will have useless data. I am connected to the CORS network for my RTK corrections and sending corrections to the drone (rover) via local NTRIP through my phone hotspot. Please tell me what I am doing wrong.

I want to try to eliminate a majority of my GCP’s to save time but I need to drone images to be onNAD83 and NAVD88 (ellipsoid 18) I don’t see anywhere to adjust these settings or change them at all. My concern is that the receiver will tag all of my photos at ellipsoid height and the map I generate will be useless without a massive amount of post-processing.

The idea is to set up the base and burn two checkpoints vs 10 GCPs all over a site to save time but I am afraid I am not going to get the correct data. Forgive me if this is simple. I am a newbie to using the drone and EMLID

The only time you will see grid and orthometric heights is when using the rover. Everything about the drone and base is LLH and the data is transformed out of the processing software. I recommend not using GCPs with RTK and allowing the corrections to do their job. This maintains the best relative accuracy. In this workflow you would still shoot 2-4 points but only use them post processing for a vertical adjustment.

1 Like

I will add though you might have to use GCP’s if you don’t have a known point or can’t RTK in a point. Otherwise you’d have to do some PPK or PPP to get the base coord and have to shift everything which is no fun. If I know this is going to happen I will run the base out before I need to fly which can be a scheduling pain if they want it tomorrow. :wink:

2 Likes

No need for a vertical adjustment if the base is setup properly, the GCPs are really just 3d check points

so the point of RTK is not to eliminate the steps of the workflow. That seems grossly ineficient

GCP’s are not just checkpoints. They are used in processing and modify the image locations away from the RTK values according to the “visual” aspect. We have run a LOT of testing and is happens no matter how low you set your trust levels. Checkpoints are used after the processing to rectify the data but they in no way affect the relative accuracy of the reconstruction.

Sorry I don’t understand understand the implication. It eliminates the need to set GCP’s. Two checkpoints work but give you no check in the control. Three checkpoints is good for sites up to about 100 acres. We use 4-5 checkpoints for very large sites and I have never had to use more than five.

Being that GPC’s are part of processing you need separate checkpoints regardless so yes you are mitigating a good bit of workflow that is very man-hour intensive. People not doing these checks are doing our industry a disservice. Especially if you are advertising your deliverables as survey-grade. If you haven’t even been or worked directly with a good RPLS you couldn’t imagine how many checks go on in their work.

1 Like

Hi Andrew,

Sorry for the delay!

All of my jobs are working in state plane (NAD83 and NAVD88 geoid 18). I was hoping I would get my base location on the same datum so I can easily glance at it and know it’s close.

You can find the Reach coordinates in the desired coordinate system and vertical datum and use them to set up the base. It works as follows:

  1. Create a new project in Emlid Flow.
  2. Collect a point.
  3. Pick the base coordinates from a survey project as described in this Support tips post.

I am also worried that the photos for the drone will be tagged at ellipsoid height so I will have useless data.

RTCM3 corrections work with geographic coordinates only. So, your base will send the LLH base position even if you set it in local coordinates in Emlid Flow. As Michael said, adjusting the results to the particular coordinate system and vertical datum is usually done in the processing software. It should be possible to use some GCPs for it.

2 Likes