Ground Control - Principle 5

5. Measure GCP's With Same GPS System You Are Using For Machine Control

ALWAYS, and only, measure in your ground control with a rover that is fully calibrated to the site control for your GPS system. Take the time to check your GPS system to make sure it is accurate that day.

In the end, the only thing that matters is that your drone data lines up with the Engineer's design, your takeoff and your machine control model. If it does not, you will not be able to use the data for volume calculations or to measure production over the duration of you project.

For this reason, all of your ground control and check shots should be measured in with the same base/rover GPS setup you are using for machine control. By using the same GPS system, calibrated to the correct site control, you will be guaranteed that your drone data will work in conjunction with any data collected on your site, past, present and future.

Man measuring Ground Control Point with GPS Rover

To measure each ground control target or check shot, just place your rover in the center, level up and take the topo shot - just as shown in the photo to the left. Use a bi-pod if you have one. Your drone data can't be any more accurate than your ground control. A little extra effort here pays off here.

Give the point a simple description in your controller, like GCP1SW, for "ground control point 1 south west". A simple description like that will make your field work much easier to sort out for your data company or someone back at the office. It's nice to paint the GCP # next to the target, but that's not 100% necessary.

For topo check shots, label them "check" or "CK". Any check shots that are in an important spot like a flow line or tie-in just need to be labeled them clearly.

When it's time to export the points you can use the proprietary file type your GPS brand uses or a universal file type like CSV or TXT. However you export the data be sure to select the Point #, Northing, Easting, Elevation and Description fields.

That's it. Five simple to understand principles you can quickly apply to any drone mapping project. If you still need to make the jump and add a drone to your fleet, give the Quantum Flight Pack a look.