Owners just bought me a Phantom 4 RTK and Pix4D Mapper. I've had my Part-107 for a bit now. After a few days of research and experiments and I think I'm going to return the DRTK-2 unit that came with it and just use my R10 if I ever find myself in an area with no cell signal or if NC's VRN is down.
Has anyone here experimented with using their own receivers for corrections? I'm looking forward in time to my next GNSS receiver purchase and am curious if anyone has used Carlson/Hemisphere, R12 or other receivers to provide corrections to their drones. I swear every time I trust a salesperson, even one who has an incentive to make me happy, I get burned. The DRTK-2 is about the clunkiest piece of crap I've seen. I get that most drone dudes and dudettes aren't into the accurate and precise game, but the dealers should key in on the differences between recreational users and professionals.
Anyway, I need a survey grade GNSS receiver that can occasionally connect to the P4RTK but will mostly be used to connect to a tough pad running Carlson SurvCE with the GIS extension for Asset Inventory Assessment.?ÿ Any advice would be greatly appreciated.
I guess the first thing to say is Congrats on your new Photogrammetry career. 😉
Second, Have you tried to just connect via bluetooth to test out the workflow potential for your gear i.e. not the Dirty K?
I don't plan to ever be something I can't spell.
Carlson/Hemisphere are great. BTW, Stonex uses Hemisphere boards for some of their products. Had a 700A out in the wild the other day and it did very well in some pretty poor conditions.
The hemisphere boards also have access to their Atlas system, which provides pretty much global corrections via satellites (no cell, no base). I did some tests a few years ago with Atlas and it was within the claimed specs.
Dont send back the DJI RTK setup till you verify that you can make the workflow funtional with your base and corrections. Besides, who can't use another base, if only for redundancy. One bad day and it pays for itself.
I worked with a surveyor in San Diego who told me that when she received her license from the state, she found that they had misspelled her title as 'professional land surveyer'. This was quite a few years ago now, but I wonder how that one even happened. Isn't the Board using some sort of template for these??
surveyer
Unfortunately, the trend to consider accurate spelling optional has propagated to even highly-educated people.
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And get off my lawn.
Anyway, I need a survey grade GNSS receiver that can occasionally connect to the P4RTK but will mostly be used to connect to a tough pad running Carlson SurvCE with the GIS extension for Asset Inventory Assessment.?ÿ Any advice would be greatly appreciated.
Huh! You haven't looked into this much. That just doesn't exist. The P4RTK can't be navigated by any other local base except the DRTK-2. It uses the wifi from controller, not a radio like your RTK does. The only other way is NTRIP. You may be able to setup an Adhoc NTRIP, but I think you need cell coverage.?ÿ
The only problem with the DRTK-2 is the software.?ÿ You have to manually?ÿ enter the Lat,Lon,Ellht in GS software. The CORS is often too far away for good results. I suggest you learn to use PPK with your local base. The is the most reliable and accurate.?ÿ
I'm with Lee on the PPK. Much more reliable and accurate. And for the best vertical results, I have found that ground control points or photo ID points are still a necessity.?ÿ
I second PPK.
I've already connected the P4RTK to NC's VRN.?ÿ In the last four years, I have yet to be in an area where I could not get enough signal to connect to the VRN so I'm only looking for a workaround in the odd event that the VRN is down.?ÿ?ÿ
I don't ever use RTK with a dedicated base.?ÿ So, yes, I need to continue to learn.?ÿ I've watched a video of a guy hooking his R10 up, but I haven't tried it yet.?ÿ It's hard for me to believe that if I can't them to communicate even if willing to stay right next to my R10 or other similar receiver.?ÿ?ÿ
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Like I said if your base will broadcast NTRIP, then you can use it with P4RTK. You will need to use wifi and have a known ip address.
Have you ever verified your drone projects in the last four years? You can't verify with RTN, you must use EDM. NSPS spatial stabards require verification to be done with a procedure three times more accurate than your original measurements. I would guess you have 0.5ft out liers (or larger) in your work, with you knowing it.
Log one second epochs on your base and look into PPK, not that difficult.?ÿ
This is the first UAV our company has purchased and we have not performed any aerial surveys with it yet.?ÿ We've only been using modern GNSS receivers for four years and in that time I have had no need for the slightly more accurate base/rover RTK surveying. This is likely due to the robustness of NC's VRN, adequate Verizon cell coverage and the types of work my company focuses on, rural water and sewer utilities and landfills.
Phase One of drone implementation has one goal: get me and my crew out of trash. 0.1' of relative accuracy will suffice but 0.2' wouldn't be a deal breaker.
I intend to verify absolute accuracy with a combination of static GNSS occupations, averaged 3minute VRN occupations and closed traverses. This year, I will be flying a few of my landfill volumes after I finish surveying them by traditional means to get a rough comparison. I grasp that I can't confirm absolute accuracy of a photogrammetry mission with my R10 on NC's VRN if the drone is also connected to the VRN, but I don't see why I can't take spot checks with the R10 on tops and toes to guard against blunders.
I'm guessing my workflow will look a bit like this in landfills that we've designed and managed for decades:
1.Set permanent GCPs outside the perimeter of the AOI. Through a combination of static, VRN, traditional surveying, and Star*Net, tie them all down.
2.On the day of flight, set a few paper plates, with trav nails driven through the center, in my AOI with a preference for high and low elevation areas.
3.Locate the temporary GCPs with my R10 connected to NC's VRN with as much time separation as possible but with the understanding that I'm looking for relative accuracy not SPCS accuracy.
4.Fly the site at around 200' or higher in the standard DJI 3D pattern. This is just a guess based on the P4RTK camera, my accuracy needs, and my ability to easily view and register my GCPs.
5.Register and stitch pics in Pix4D Mapper.
6.Export .las file and import into Autodesk Recap. Reduce point cloud by around 90% and export .rcp file.
7.Import .rcp into C3D and generate a surface.
I should add that one of our drafters spent a few years working for a photogrammetrist. He has both technical and practical experience on the processing end.
I know I'm going to bungle it up a few times but that's how I learn best. The balance between altitude, light conditions, wind conditions, and ground cover is somewhat daunting. It will likely be more than a year before I am comfortable enough to use it for anything other than coarse topo, inspection, and site specific ortho photos.
For landfills and dirt sites the VRS should work well for you so long as you have good cell service and less than 5 miles from the VRS base. If you lose RTK lock during flight this will be shown in coordinate quality within pix4d. DJI ground station has a new feature to maintain RTK correction for a short duration when the radio is lost. If you have enough ground control, this may be sufficient. If your R10 can collect 1-second static, best practice to use this also. The P4RTK automatically stores the static data for PPK post-processing. You could try to post-process PPK data using a CORS if it is close enough.
Landfills around here can be 200ft change in terrain. To maintain a 200ft AGL you would have to use Terrain Awareness in DJI GS. You'd have to fly at 400ft above the lowest terrain while being 200ft above the highest terrain when using a constant AGL.
Thanks for the insights.?ÿ I can and will collect at 1-second static.?ÿ?ÿ
One of the reasons I'm considering returning the DRTK-2 Base (not the Phantom 4 RTK drone) is the difficulty of using it over existing control.?ÿ Something as simple as entering an antenna height becomes a bit of a hassle.?ÿ?ÿ
Have you used the P4RTK with the DRTK-2 base??ÿ?ÿ
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