Mapping with RS2+ and Matrice 350 - Elevation issues

I was using a RS2+ with a Matrice 350 for a mapping mission with Terrain following. I setup the RS2+ Over a known point and entered that manual point. I then used NTRIP to the M350 to get the data. All good there. I then setup the mapping mission using terrain following. I set the mission to be 160 feet above the terrain. When it started flying it was flying really low so I aborted. I then figured out the drone was not getting the ellipsoidal WGS84 height. I then used my current location to get the difference between WGS84 and Ortho height which was 111 feet I reduced my base height by that amount and it was dead on. So for whatever reason the base is not sending the correct height to the drone. When you set up the base elevation in the setup menu there’s no input for the elevation model you are using which in my case is WGS84. Any input?

The only explanation that makes sense to me would be that the elevation value from your known point’s datasheet is orthometric and not ellipsoidal. Is it explicitly declared as such? Around here, the datasheets have both values stated in different sections.


Hi @dave1,

Sorry, it was so quiet here. I agree with @Gabriel_C. The rover’s height is related to the same datum as your base. Thus, it’s vital to enter the correct ellipsoidal height.

It’s possible to enter the base position with orthometric height. You can create a project with the WGS84 coordinate system and select the proper geoid model. Then, add your known point by entering its coordinates. So, while setting your base, you can select this point from a project. Emlid Flow will convert these coordinates into geographic ones.

We have a support tip about setting the base using local coordinates and orthometric height.