Now, let�s look at the alternatives that we can use at site in place of GCPs.
The best alternatives are - using RTK or PPK with your drone.
In these methods, the base station setup is on ground as described in the GPS system section of the previous lecture.
The rover however is now the drone instead of the on ground GPS receiver! The GPS correction system
can be RTK or PPK.
I strongly recommend using a PPK correction system over the RTK correction system for the following reasons -
The RTK system of correction needs a continuous radio link between the base station and the drone.
Given that the drone is most likely going to be flying at great distances away from the base station,
there will be a high possibility of obstructions like buildings coming in the way of the radio link -
this can result in loss of correction data.
The PPK system of correction however doesn�t need a radio link for correction data transmission.
Data is logged in the drone and processed with data from the base station
after the mission is completed .. Hence, there is no risk of data or initialisation loss due to radio link outages.
Some popular drones that have both RTK and PPK correction systems are the ebee plus and DJI M600 series
Both systems have RTK to PPK fallback enabled in case there is radio link failure during the flight.