Old surveyor trying to understand the drone world. I get that RTK is real-time corrections and PPK is post-processed. But when would you choose one over the other?
My instinct says real-time is always better but I keep seeing people say PPK is more reliable. What am I missing?
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Sign inRTK is great WHEN IT WORKS. The problem is it needs constant connection to corrections - either cell network for NTRIP or radio link to a base. If that connection drops mid-flight, some photos get corrections and some don't. You might not even notice during the flight.
PPK logs everything on the drone, then you apply corrections after. Every photo gets corrected or none do. No partial failures. That's why it's more "reliable" even though it's not real-time.
I work remote sites in Alaska. Cell coverage is a joke. PPK is the only option and honestly I prefer it now even when I have coverage.
Good summary Pete. I'll add:
Use RTK when:
Use PPK when:
Many of us use RTK during flight then ALSO run PPK after as a backup. DroneDeploy calls this Auto-PPK. Best of both worlds.
The other thing is PPK lets you use CORS stations after the fact. If your base had an issue or you didn't set one up, you can still get corrections from the nearest CORS. Obviously not as accurate as a local base but it's a nice safety net.
I've salvaged a few flights where my base died by processing against CORS. Can't do that with RTK-only.
Exactly Tom. Same principle - redundancy and verification. The old surveying fundamentals apply, just with new tools.
This makes a lot of sense. So PPK is like insurance - even if everything works with RTK, you have the data to reprocess if needed. And if RTK fails, you're not dead in the water.
Kind of like how we always close our traverses even when we trust the measurements.
One more thing - some processing software handles PPK better than others. DroneDeploy's Auto-PPK is dead simple, just upload and it figures out the corrections. Pix4D requires more manual steps. Factor that into your workflow decision.