To PPK or to RTK, is that the question?
Oh we do love our acronyms in surveying, don’t we?! Scroll to the end for a useful glossary we put together to help out.
So, you want to be down with the kids and get into RPAS aerial mapping. Your young surveyors recognise the importance of embracing new technology, but you also need to be reassured that these things can actually deliver the goods and not just give your field parties an excuse to fly toy planes all day at work.
You need survey-grade results, which means you rule out the plethora of hobbyist drones that are out there and that your kids probably have on their Christmas lists.
There are a few different ways to get there, namely via RTK or PPK positioning technology. These acronyms mean business! They mean accuracy! They also go about getting it in slightly different ways.
RTK relies on GNSS positioning and requires a stable radio link between a base station on the ground and a GPS antenna on board the RPAS. This gives the user real-time processing on the go, which is the norm for land-based survey rovers and machine-mounted GNSS solutions. An advantage with an RTK solution is having the ability to control your RPAS with cm precision such as the MAVinci Sirius Pro’s new RTK spot landing feature. This allows the operator to take a cm position prior to launch and have a fully autonomous RTK assisted landing spot landing within a 5m radius (subject to conditions).
When it comes to aerial mapping, RTK positioning can have its downsides, with radio link outages and GNSS signal blocks. Due to the long distances between the drone and the base station, signals can be obstructed and this results in loss of correction data and a lower percentage of accurate camera positions in the flight.
PPK, on the other hand, processes the positioning information after the flight, not during. Data is logged in the aircraft and combined with data from the base station when the flight is completed. As a result, there is no risk of data or initialisation loss due to radio link outages. The processing is similar to RTK, however PPK is a little more thorough as it traces back and forth through the data multiple times to give more comprehensive results.
So when it comes to survey-grade results with aerial mapping, PPK can deliver more reliability and longer range from the base station to give users greater flexibility.
RPAS – Remotely Piloted Aircraft System
UAV – Unmanned Aerial Vehicle (also referred to as UAS, Unmanned Aerial System)
RTK – Real Time Kinematic
PPK – Post Processed Kinematic
GNSS – Global Navigation Satellite System (includes all satellite constellations, United States GPS, Russian GLONASS, Chinese Beidou, Japanese QZSS, Indian IRNSS)
GPS – Global Positioning System (the US-run satellite constellation, commonly referred to in place of GNSS)