[UAS] DJI drones vs American drones

[Gootee, Brian F. - (bgootee)]

Rosa,

Yes, I’ve seen some Bad Elf in use with RTK and they said something very similar, to have it fully unlocked, but they used their FLEX with hardware other than drones. I’d consider Bad Elf with RTK if it replaced the need for GCPs. I’ll definitely look at Skydio and Parrot options. We would like to have the option to use a thermal camera for earth fissures and landslides, so a medium-duty like the Matrice is what we would use, if not too expensive.

Amanda, I think testing our equipment at an earth fissure would be fantastic. Ann Youberg, Becky and I have a couple of ideas on how to apply UAV to fissure mapping. I’ll definitely circle back to you on that.

All very helpful input. I’m curious what Jeff’s response is to whether GCPs are needed with a RTK system. I’m sure GCPs will make for a better solution, but the tradeoff is time and safety placing and retrieving targets.

Brian

Brian F. Gootee
Research Geologist, P.G. | Basin Analysis | Geologic Mapping | Tribal Liaison
Arizona Geological Survey<http://azgs.arizona.edu/> | University of Arizona
bgootee at arizona.edu<mailto:bgootee at email.arizona.edu>

From: Bevington, Rosa K - (rosa) <rosa at cals.arizona.edu>
Sent: Thursday, July 28, 2022 8:55 AM
To: Hughes, Amanda Nicole - (anhughes) <anhughes at arizona.edu>
Cc: Gootee, Brian F. - (bgootee) <bgootee at arizona.edu>; Joe Wagner (FCD) <Joe.Wagner at Maricopa.Gov>; Gillan, Jeffrey Kent - (jgillan) <jgillan at arizona.edu>; Rahr, Matt - (rahr) <rahr at ag.arizona.edu>; Beers, Rebecca - (rebeccabeers) <rebeccabeers at arizona.edu>; uas at list.cals.arizona.edu
Subject: Re: [UAS] DJI drones vs American drones

Hi Brian,
Have you heard of the Bad Elf Flex?
https://bad-elf.com/pages/flex
It has 1cm accuracy with RTK via NTRIP. I have been using this system and love it. It’s $6000 to have it completely unlocked and RTK ready.
I fly an old DJI Inspire 1 and am also looking into getting another drone besides DJI (though I wish I didn’t have to). I’ve heard good things about Skydio and Parrot. Parrot has some thermal options and RGB options. I’m looking for multispectral options, so I’m still looking (if anyone has suggestions for a RTK multi-rotor, please email me)

Jeffrey, do you think GCP’s are still needed even if you have a drone with RTK capabilities? I was hoping that this was not the case but heard otherwise and wanted your opinion on it.

Thank you all, I enjoy these discussions!


On Jul 27, 2022, at 8:19 PM, Hughes, Amanda Nicole - (anhughes) <anhughes at arizona.edu<mailto:anhughes at arizona.edu>> wrote:

Hi Brian,
In our group, we’ve been doing SfM to create virtual outcrops to look at and extract quantitative information about geologic structures. We had been using a DJI drone, but we just got a Skydio one for some of the reasons mentioned; in addition, it is very easy to fly and has really nice built-in obstacle avoidance that ensures no collisions—especially helpful around trees and cliffy outcrops. We use DroneDeploy to plan our acquisitions, Agisoft Metashape to process SfM, and CloudCompare for most postprocessing (but some in Matlab too). We also just got a set of Emlid Reach RTK instruments to get ~10 cm accuracy on ground control points; I went to a UNAVCO workshop to learn how to use them and they are pretty easy, but I am not an expert with them yet; you are welcome to come check them out and see what you think! They were way less expensive than Trimbles, and seem to work great for the scale that we need, which is similar to your applications as well. We had been thinking about testing out our new setup locally on a fissure and would love to coordinate with you all on that if that would work out! Happy to discuss more,
Best regards,
Amanda

Get Outlook for iOS<https://aka.ms/o0ukef>
________________________________
From: UAS <uas-bounces at list.cals.arizona.edu<mailto:uas-bounces at list.cals.arizona.edu>> on behalf of Gootee, Brian F. - (bgootee) <bgootee at arizona.edu<mailto:bgootee at arizona.edu>>
Sent: Wednesday, July 27, 2022 6:03 PM
To: Joe Wagner (FCD) <Joe.Wagner at Maricopa.Gov<mailto:Joe.Wagner at Maricopa.Gov>>; Gillan, Jeffrey Kent - (jgillan) <jgillan at arizona.edu<mailto:jgillan at arizona.edu>>; Rahr, Matt - (rahr) <rahr at ag.arizona.edu<mailto:rahr at ag.arizona.edu>>; Beers, Rebecca - (rebeccabeers) <rebeccabeers at arizona.edu<mailto:rebeccabeers at arizona.edu>>; uas at list.cals.arizona.edu<mailto:uas at list.cals.arizona.edu> <uas at list.cals.arizona.edu<mailto:uas at list.cals.arizona.edu>>
Subject: Re: [UAS] DJI drones vs American drones

Joe and Jeffrey,

Many thanks for the excellent perspectives Joe. When I used to attend ASLD UAS group I remember you always had a ton of useful information as you do here. I’ll definitely look into those other products and systems. I’ve always wanted to use or hear of others using the AeroPoints. I presume post-processing or processing fees apply every time you need them. No need to reply since I can look into that. I’m pretty stoked to look into other aircraft. I agree, the trajectory of DJI doesn’t look good.

For context we typically survey post-fire and pre-debris flow changes, or at least we’d like to do both but haven’t done too many change studies. Mostly we’ve used the onboard GPS to do dirty scans, but try use hand-placed GCP targets surveyed by Trimble d-GPS units, fly and then post-process with Agisoft Metashape. Our Trimble GeoXH units are dying and probably won’t last til the end of this year, but those units are too precise for our needs (10-20 mm) and are very costly to replace. At the end of the day we would be fine with ~10 cm field accuracy for most of our projects (landslides, earth fissures, fire scars, geomorphic features). Most of our projects are quite remote and rugged and usually less than 1 km2 but as large as 2x4 km.  So RTK alone with occasional GCP may work but we’ve never used RTK. We have about 300,000 km on a DJI P4P and it’s still going, but they can’t last forever so we’re looking to replace/augment it.

That said, Joe if you do have any PowerPoint slide decks that address the scope of our needs that would be very helpful for Becky and I. We are the two pilots at AZGS.

Jeff, if you have time tomorrow I’d like to take you up on the offer to chat over the phone?

Kind regards, Brian

Brian F. Gootee
Research Geologist, P.G. | Basin Analysis | Geologic Mapping | Tribal Liaison
Arizona Geological Survey<http://azgs.arizona.edu/> | University of Arizona
bgootee at arizona.edu<mailto:bgootee at email.arizona.edu>

From: Joe Wagner (FCD) <Joe.Wagner at Maricopa.Gov<mailto:Joe.Wagner at Maricopa.Gov>>
Sent: Wednesday, July 27, 2022 4:53 PM
To: Gillan, Jeffrey Kent - (jgillan) <jgillan at arizona.edu<mailto:jgillan at arizona.edu>>; Gootee, Brian F. - (bgootee) <bgootee at arizona.edu<mailto:bgootee at arizona.edu>>; Rahr, Matt - (rahr) <rahr at ag.arizona.edu<mailto:rahr at ag.arizona.edu>>; Beers, Rebecca - (rebeccabeers) <rebeccabeers at arizona.edu<mailto:rebeccabeers at arizona.edu>>; uas at list.cals.arizona.edu<mailto:uas at list.cals.arizona.edu>
Subject: [EXT]RE: DJI drones vs American drones

External Email
Brian,

Good afternoon. The Flood Control District currently uses DJI products for our design projects. We use Bentley ContextCapture and ESRI Drone2Map for SFM processing. Drone2Map is a backup and not used very often. We have our surveyor set ground control and I use the Propeller AeroPoint GPS mats. These GPS targets are extremely helpful when flying in remote areas where typical photo id ground control is hard to find or there is no time for a surveyor to set targets. Very accurate and very easy to use.

As far as DJI, I will never purchase another DJI product, here at work or for personal use. They are absolutely wonderful aircraft and I work them hard in 105+ degrees heat. I wholeheartedly agree with the federal government crackdown and have been unhappy with their involvement in Ukraine.

My next purchase will be a fixed wing aircraft – Quantum Systems Trinity F90+ or the Wingtra One GEN II. My wife flies drone for The National Weather Center and NOAA and uses the Trinity F90+ and loves it. She and I both have been looking for drones comparable to DJI and they are hard to find. I’m not impressed with the Skydio 2 system. It doesn’t seem as functional as the Mavic systems.

I have several projects that I have used to present a PowerPoint presentation to local folks. If you like I can ftp them to you to look over.

Sincerely,

Joseph G. Wagner
Mapping, Surveying, and CAD Manager
Drone Program Manager

<image001.png><http://www.fcd.maricopa.gov/>
Flood Control District of Maricopa County
2801 W Durango St, Phoenix, AZ 85009
(O) 602-506-2203 (C) 623-297-2638
Joe.wagner at maricopa.gov<mailto:Joe.wagner at maricopa.gov>
www.maricopa.gov/floodcontrol<http://www.maricopa.gov/floodcontrol>




From: UAS <uas-bounces at list.cals.arizona.edu<mailto:uas-bounces at list.cals.arizona.edu>> On Behalf Of Gillan, Jeffrey Kent - (jgillan)
Sent: Wednesday, July 27, 2022 3:57 PM
To: Gootee, Brian F. - (bgootee) <bgootee at arizona.edu<mailto:bgootee at arizona.edu>>; Rahr, Matt - (rahr) <rahr at ag.arizona.edu<mailto:rahr at ag.arizona.edu>>; Beers, Rebecca - (rebeccabeers) <rebeccabeers at arizona.edu<mailto:rebeccabeers at arizona.edu>>; uas at list.cals.arizona.edu<mailto:uas at list.cals.arizona.edu>
Subject: Re: [UAS] DJI drones vs American drones

Hi Brian,
I have a lot of experience surveying terrain with drones using RTK and ground control methods. I would be happy to chat with you any time about it. In general, RTK is fantastic but best referencing practices could depend on your specific application. I have recently done some drone stuff with Ann Youberg on Mt. Lemmon.


Jeff Gillan, Ph.D.
Data Scientist III | Drone Pilot
School of Natural Resources & Environment
University of Arizona
gillanscience.com<http://gillanscience.com>
(530)339-5975<tel:(530)339-5975>

________________________________
From: UAS <uas-bounces at list.cals.arizona.edu<mailto:uas-bounces at list.cals.arizona.edu>> on behalf of Gootee, Brian F. - (bgootee) <bgootee at arizona.edu<mailto:bgootee at arizona.edu>>
Sent: Wednesday, July 27, 2022 3:40 PM
To: Rahr, Matt - (rahr) <rahr at ag.arizona.edu<mailto:rahr at ag.arizona.edu>>; Beers, Rebecca - (rebeccabeers) <rebeccabeers at arizona.edu<mailto:rebeccabeers at arizona.edu>>; uas at list.cals.arizona.edu<mailto:uas at list.cals.arizona.edu> <uas at list.cals.arizona.edu<mailto:uas at list.cals.arizona.edu>>
Subject: Re: [UAS] DJI drones vs American drones

Matt,


Nice to know about the pursuit for DJI drones is continuing. Their hardware and software are really good and stand up to time well.


In addition we wonder who else is using structure-from-motion to build DEMs and what methods for georeferencing they are using. The purchase of a new drone with or without RTK and a GPS system are what is relevant to us here.


Many thanks for your help. Brian


Brian F. Gootee
Research Geologist, P.G. | Basin Analysis | Geologic Mapping | Tribal Liaison
Arizona Geological Survey<http://azgs.arizona.edu/> | University of Arizona
bgootee at arizona.edu<mailto:bgootee at email.arizona.edu>


From: Rahr, Matt - (rahr) <rahr at ag.arizona.edu<mailto:rahr at ag.arizona.edu>>
Sent: Wednesday, July 27, 2022 3:03 PM
To: Beers, Rebecca - (rebeccabeers) <rebeccabeers at arizona.edu<mailto:rebeccabeers at arizona.edu>>; uas at list.cals.arizona.edu<mailto:uas at list.cals.arizona.edu>
Cc: Gootee, Brian F. - (bgootee) <bgootee at arizona.edu<mailto:bgootee at arizona.edu>>
Subject: RE: DJI drones vs American drones


Hey Rebecca and Brian,


Let’s ask the UAS User Group. We just bought a DJI Mavic 3 and have two other DJI drones, and agree, they’re great for the price.


From: Beers, Rebecca - (rebeccabeers) <rebeccabeers at arizona.edu<mailto:rebeccabeers at arizona.edu>>
Sent: Wednesday, July 27, 2022 12:31 PM
To: Rahr, Matt - (rahr) <rahr at ag.arizona.edu<mailto:rahr at ag.arizona.edu>>
Cc: Gootee, Brian F. - (bgootee) <bgootee at arizona.edu<mailto:bgootee at arizona.edu>>
Subject: DJI drones vs American drones


Hi Matt,


This is Rebecca Beers at the AZ Geological Survey. My colleague (Brian-copied) and I are curious if the University has a recommendation on an American-made drone? We are looking to purchase a new drone for our department, but I remember an email coming out a while ago stating that the University may not allow Chinese-made drone (DJI) in the future over concerns of metadata leaks. Have you heard anything else on this? We really like our seamless functionality of DJI, but we are curious if you have found any American-made drones with similar capabilities as the DJI drones? Or has the University stepped back on the concerns of DJI metadata leaks?


Thank you, and we appreciate any guidance you have on this,
-Becky




---
Rebecca Beers
Research Geologist III
Arizona Geological Survey,
University of Arizona
www.azgs.arizona.edu<http://www.azgs.arizona.edu/>
rebeccabeers at email.arizona.edu<mailto:rebeccabeers at email.arizona.edu>


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