RTK vs. PPK Drone Mapping: What’s the Difference?

What's the difference between RTK and PPK?

PPK is another GPS correction technique that is becoming increasingly popular similar to RTK. both RTK and PPK allow users to accurately locate the position of a UAV without relying on measuring ground targets. However, there are significant differences between these two mapping technologies in terms of workflow, accuracy, etc. Let's have a look in detail:

The two techniques are very similar, however, PPK has a decisive advantage, because of its robustness and high accuracy.

Position correction occurs at different times

Basically, the main difference between RTK and PPK is the time it takes for the position correction to occur. RTK makes the correction during the flight, which saves time in post-processing, and you can see the coordinates and accuracy of the measurement points on the mobile station. But PPK is corrected after the flight, so you can't see the coordinates in the field.

PPK is more accurate

Ideally, the accuracy of PPK is the same as that of RTK. However, RTK requires real-time corrections to its base point, which is done through the data chain, which can be affected by momentary interruptions. On top of that, you have to add possible problems or errors due to improperly parked bases that can make your position off or inconsistent.

In contrast, PPK is a more robust and accurate solution because it does not rely on a continuous data chain. In addition, field commissioning is faster because you don't necessarily need to know our position from the base before the flight; it can be done after the flight. There is no onboard data to receive, compare and calibrate, which greatly reduces the performance latency of the UAV and thus increases accuracy.

PPK drones offer users greater flexibility

To perform at its best, an RTK drone must follow a pre-planned flight path that is optimized to make it easier for the photogrammetry software to complete its work as quickly as possible. Since the data stitching of PPK drones is done after the flight, they are not limited to any particular flight path, giving them the freedom to collect photographic data and allowing the pilot to map the area to his satisfaction.

PPK has a larger working radius

GPS RTK work is restricted by the communication station, and the working distance is generally not more than 10km. Using the PPK technology, the general working radius can reach 50km.

Conclusion

Both RTK and PPK positioning can reach centimeter accuracy. However, the downside of RTK positioning lies in its reliance on a data link that allows real-time corrections to the drone's GPS position to be performed.

The non-dependence of PPK positioning on any data link with the ground station makes it a more robust GPS correction technique. Therefore, whenever possible, it will be preferable to use PPK positioning rather than RTK.

Only in very specific situations where time is a determining factor (such as immediate topographic surveys in areas that have just suffered a natural disaster) may RTK positioning be preferable over PPK.