Joined about 2 months ago
QA/QC obsessed, checkpoint queen
on Can't get RTK fix - systematic troubleshooting checklist
Great list for beginners. I'd add one more - check the satellite constellation status before you head to the field. There are times during the day when satellite geometry is poor for your area (high PDOP). Apps like GNSS Planning or Trimble GNSS Planning Online show you the best and worst windows. Most people don't bother with this but if you're working in challenging environments it can be the difference between fix and float.
on NTRIP vs radio link for base-rover corrections - pros and cons
Don't overlook Starlink as a third option for remote NTRIP. We added a Starlink Mini to our kit and it covers most of the "no cell coverage" scenarios. More reliable than a cell booster and works in places where radio line-of-sight would be tough. But yeah, having radio as a last resort backup is smart. Belt and suspenders.
on Setting up a permanent RTK base station for repeat survey work
Love this setup. One thing I'd add - make sure you have a way to monitor it remotely. We have a similar permanent base and I set up a simple script that pings the caster every 5 minutes and sends me a text if it goes down. Saved us a wasted trip twice already. Also curious how the RS2+ holds up long term outdoors. Those things aren't exactly weather sealed for permanent installation.
on Flight overlap settings - am I wasting time with 80/80?
Did this test last year. Same 5-acre site, flown at 80/80, 75/70, and 70/65. Results: - 80/80: 1.2cm RMSE on checkpoints - 75/70: 1.4cm RMSE - 70/65: 2.1cm RMSE The jump from 75/70 to 70/65 is where quality drops noticeably. I fly 75/70 as my standard now. The time savings are real - about 30% fewer images to process too.
on Flight altitude vs GSD tradeoffs - when to fly higher?
GSD should be driven by deliverable requirements, not ego. For most construction topo, 2-3cm GSD is plenty. You're not detecting features smaller than that anyway. I fly at 300-400ft for routine work. Drop to 200ft only when I need sub-2cm for specific features.
on Women in drone surveying - finding your crew
15 years in surveying, 5 in drone work. It's gotten better but there's still work to do. My advice: get your certifications, build a solid portfolio, and find a mentor regardless of gender. The WTS (Women's Transportation Seminar) also has a UAS working group that's worth checking out.
on GCP placement strategy for long linear projects
20 GCPs over 3 miles sounds about right but make sure you have them at both ends and at any elevation changes. Road corridors tend to have subtle grade changes that can fool the processing. I'd go 18 GCPs and 10 checkpoints. The checkpoints are where you prove your accuracy to the client.
on What overlap settings are you using for construction sites?
75/75 is safe but probably overkill for flat sites. I use 70/70 for general construction topo and 75/75 when there's structure or significant vertical features. For pure earthwork on a flat pad, you could probably get away with 65/65 and still have plenty of tie points. But storage is cheap and processing isn't that much longer with more overlap. I'd rather have too much than not enough.
on Coordinate system headaches - NAD83 vs WGS84 vs local
Document everything upfront. Before flying, confirm: what datum, what projection, what epoch, what units. Make a project sheet. For transformations, I use QGIS with the proj library. Free and handles almost any conversion. Civil3D's coordinate tools are decent too.
on Ground control targets - what brand/size are you using?
I use 24" fabric targets from SurveyMarkers.com for anything over 300ft AGL. Below that, 12" works fine. The key is contrast - black and white checkerboard shows up in everything. Avoid the ones with small patterns. You want 4 quadrants, max contrast.
on Building a portfolio for drone survey work
Map your own property or a friend's land. Full workflow from planning to deliverable. Shows you can do the work without any NDA issues.
on Coordinate systems in DroneDeploy - how do you handle state plane?
To add to Craig's answer - if you're using RTK/PPK, your corrections are coming in as WGS84. DroneDeploy handles the transformation during processing as long as you specify the output system. The gotcha is vertical datum. Make sure you're clear on whether client wants ellipsoid heights or orthometric (NAVD88). That setting is separate from the horizontal system.
on Stockpile accuracy - how close are you getting to scale tickets?
Worth noting that your GSD matters a lot for stockpiles. Lower and slower = more detail on the pile surface. I see people flying at 300ft and wondering why their volumes are inconsistent. For stockpiles I fly at 150-200ft AGL. Yes it takes longer but accuracy is better.
on OpenDroneMap vs paid alternatives - honest comparison?
The accuracy is there if you configure it right. Default settings won't give you survey grade. You need to tweak the processing parameters. Happy to share my settings if you want.
on RTK vs PPK - when do you use which?
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.
on How many GCPs do I actually need with RTK?
@NewbieNate I use 12" checkerboard targets from Amazon. Like $30 for a pack of 10. Spray paint works too but targets are easier to pick in the photos. Just make sure they're visible at your flight altitude.
on How many GCPs do I actually need with RTK?
OK this is my favorite topic so buckle up. RTK gives you accurate camera positions. That's it. It doesn't magically make your photogrammetry perfect. You should ALWAYS use checkpoints to validate your results, even if you're not using GCPs for processing. My workflow: RTK flight, then I set 3-4 checkpoints (not used in processing) to verify accuracy. If checkpoints are within spec, I'm good. If not, I know something went wrong. For client deliverables where accuracy matters, I still use 4-5 GCPs on a 40 acre site plus 2-3 checkpoints. Belt and suspenders.