Get Coordinates for Ground Control Points with PPK Rover

Updated: Feb 25

Using the RoboDot, it's easy to obtain precise coordinates for ground control points (GCPs). GCPs can later be used in photogrammetry projects with Pix4D, Metashape Pro, or similar software. Here's a minimalist solution to acquiring GCPs with a single RoboDot Rover and freely obtainable observations from Continuously Operating Reference Stations (CORS).


First, know where your base or CORS corrections are located relative to your project. Increasing the distance between the base and rover will decrease the accuracy of each measurement. Distances between rover and base under 20km are recommended.


RoboDot allows users to choose between mounting it on a monopole, bipod or placing it directly on the point of interest to take a PPK rover shot. If you plan on returning, consider marking the location of the GCP with paint or a surveying pin.

RoboDot Over GCP

Start by placing the RoboDot over the GCP. If you have a rod, before taking your first shot, enter the rod height in meters, then take the shot. Label it if you have to. Repeat this for every point that you need to identify. The amount of time that a point is sampled can be set on the settings page at up to 300 seconds.


RoboDot Rover Mode

When all the shots are taken, stop recording data on RoboDot.


Back in the office, download the observation and shot files from RoboDot's Files page, these files are necessary for post-processing.


RoboDot Utility Rover PPK Tool

Run the RoboDot Utility, selecting PPK Rover. Enter the rover observation file first, in order to see the time range of rover observations. This information helps to obtain the required base observations.


RoboDot Utility Rover Observation Period

Find the nearest CORS site ID using the CORS Map. Then, in UFCORS, enter the rover observation timeframe and site ID to download the relevant base observations.


In the Utility, enter the downloaded zip file under Base Obs. Alternatively, enter a file from a local base station, such as another RoboDot that would have been recording during the same period as the Rover. Finally, enter the shot list file and start processing.


After the process is complete, the Utility will generate a shot list CSV file. This file can be easily viewed and used with aerial photogrammetry software or your preferred CAD package.


Do you have a similar application? Contact us to see how we can help you solve your measurement needs.