New Workflow for Phantom 4 RTK Base Station

[@aymanbeedo7911]

Thank you for the valuable information. Please more detailed videos about Pix4d

[@sierraaeriform7348]

Greetings and thanks for the coaching on obtaining the high accuracy from the D-RTK base station. We are new to the P4-RTK and will be applying your techniques to our Pix4D processing. I really appreciate your support.

[@daltonbruce6400]

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[@huxleyronin2786]

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[@daltonbruce6400]

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[@daltonbruce6400]

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[@huxleyronin2786]

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[@chuchii109]

Hi thanks for the video! This clears up a lot of the questions. I would like to know how you are creating dummy GCP points in Pix4D and applying the same offset to each of those?

[@elijahmukwasa4694]

Hi,I am unable to link the base station to the RTC despite following all the steps. I keep getting a response saying "weak RTK signal ".

[@VictoriaAerial]

Why would we not put the mobile station over a known point? Could we not put custom coordinates to match the local system? We are getting distortions and have trouble with conversions even with the P4P RTK data which is disappointing. Our point of buying the $12 k unit was to reduce the workflows and QC, and processing issues. At most it seems to help just a little with lots of conflicting workflow suggestions. You say 3 GCPs, a qualified land surveyor told me at least 6 should be used.

[@giordanisalamon]

Hi I'm not satisfied with the quality of the pictures (they seem to be fisheye) how to solve this, some manual settings are needed regarding the focus... as we did on the Phantom 4 pro? Any suggestions on how to improve the image quality?

[@Aerotas]

Hi! The fish eye effect you see on P4RTK photos is completely normal and should not impact the quality of your data as far as photogrammetry goes. If you do need to change it, you can turn on "distortion correction", which should get rid of that effect.

[@accumapmodels]

Great video guys!

[@msurcombe]

Great video. I'm trying to translate this workflow over to the M210v2 and Metashape (in fact I'd worked out this was the way to do it before finding the video). BUT I can't see how to apply the offset in Metashape. Have you ever managed to do that?

[@nonoy01no]

Good day. Great Vid. I just have a question, we normally use more than 3 GCPs (non RTK flights) to have corrections for translation, rotation and scale. However, if we just use 1 GCP, it will just adjust for the translation, how about the rotation and scale? How can we be sure they will be/ they are already corrected for the P4 RTK system?

[@Aerotas]

Thanks for the comment! To responsibly verify the project, you are correct, a minimum of 3 GCPs are needed for any RTK project in order to verify translation, rotation, and scale. Due to the extremely tight relative accuracy produced by the P4RTK data we usually only have to use 1 GCP to bring it back to a real-world coordinate system, and then use the other GCPs as check shots to verify the integrity of the P4RTK data (checking rotation and scale). Without at least 3 GCPs you are blindly trusting the P4RTK data, which is not a good practice when it comes to survey-grade accuracy and photogrammetry. The real benefit to time savings with the RTK drones is that as projects get larger, you still only need a minimum of 3 GCPs on a project (although we recommend 5 for redundancy). For example, a 500-acre project flown RTK only needs 3 good GCPs to anchor and verify translation, rotation, and scale, whereas a non-RTK flight would require many many more to anchor and verify the same.

[@BERNARDIN_1986]

Great video, thanks for sharing. Now, by using this system (Phantom 4 - RTK) you´ve got coordinates that are exact relative to the position of the base, but not necessarily exact relative to a reference system (WGS84 ). In relation to the system of reference, the coordinates that you get with the drone are as exact as the coordinate of the base. You still have in both cases the same precision (relative and absolute positioning of the base). Is it possible to set manually the position of the base? (I use a double frecuency gnss and a PPP online system to set an absolute base coordinate)

[@Aerotas]

You've got it! Yes, it is possible to manually set the position of the base, however, we typically find it to be redundant since you'd want to use GCPs shot with survey grade equipment as check shots to verify or shift the data in either situation if you're looking for real-world accuracy as opposed to relative accuracy. Setting the DRTK 2 up over a known point and keying in the coordinates just adds an extra step to the field workflow which could introduce errors that doesn't really change the office workflow much. Thanks for the question!

[@davemorgan2850]

Thanks for the video. very informative. If you purchase the Phantom 4 RTK without the base station and choose to process using PPK is there any difference in the accuracy of the data because we aren't getting RTK positional accuracy? Also is using a custom RTK network recommended? I assume if it's not too far away it's ok? I'm thinking of getting the propeller Aero PPK kit which uses only the Phantom 4 RTK, 1 Aeropoint and the Propeller corrections network. Have you guys tested this?

[@Aerotas]

Accuracy should remain very similar if processing PPK vs. RTK. The only difference is when the corrections are made. With RTK the corrections are happening in real time using the DJI base as a point of reference. With PPK you are using a 3rd party network/base data to perform the corrections in post. We find the RTK workflow to be more efficient, although yeilding very similar results. The Propeller Aero PPK kit is essentially the same as using a 3rd party base/network, except Propeller will do the corrections for you. We have not tested that system, however. If you have any other questions feel free to reach out to [e-mail]!

[@blackswampaerialenvironmen9742]

Great video. Any input on modes 2 and 3 of the D-RTK 2 base?

[@Aerotas]

Thanks for the comment! We have not found either of the other two modes to be useful for drone survey at this time. If there are any breakthroughs we will be sure to make a video!

[@oktovianoviegastilmandejes5426]

How can we manually take pictures using Phantom 4 RTK?

[@Aerotas]

You can always select the "fly" menu from the home screen to enter a typical HUD of the Phantom aircraft. From there you can take off and fly manually and take pictures/video like you can with any other DJI drone!

[@briannjumeneh9207]

How can one apply accuracy adjustment during data processing after a 3d asset surveys using phantom 4RtK drone

[@meytimeshki]

Hi there from Australia, what computer hardware you are using for quick process? ( processors, RAM , graphics , etc , )

[@oktovianoviegastilmandejes5426]

Can DJI Phantom 4 RTK still be use, if there is no Base Station? Thanks

[@joemathieu6795]

Hi team Aerotas, great video, quick questions, how do you insert the offset in Pix4D?

[@Aerotas]

The methodology that we prefer for offsetting a project in this manner is to create a number of dummy GCPs in Pix4D, and apply the XYZ offset to their calculated positions, in order to create a consistent offset across the entire project.

[@gprsurf]

@@Aerotas The way I did this was the following: 1. Create MTPs around the site 2. Copy the XYZ data from these MTPs to an Excel spreadsheet (basically had to retype everything since there seems to be no way to export MTPs, only GCPs) 3. Apply the correction factor to the MTP XYZ measurements 4. Create a comma-delimited CSV file from the corrected MTP coordinates. 5. Import corrected MTPs as dummy GCPs into the project. Is there an easier way to do this? Thanks for your great video.

[@azadpablo]

Hi, thanks for the video, please I have a question! I have a problem with my altitude, I already made many flights but when I comparate it with a known coordinate I get a difference of 20 meters , how can I could solve it

[@Aerotas]

Hi, please download the guide from our website which should help answer this question; www.aerotas.com/dji-d-rtk-2-survey-workflow or email us at [e-mail]!

[@250624or]

it sound like your issue may be a geoid seperation (elipsoid vs. orthometric height issue)

[@احمدعلى-د4م4خ]

How much does a drone cost and how accurate is it compared to lifting the ground?

[@irpan_ilmi]

Can it be used to do a mission without the base station ? Due to some limitation, I can't take the base station with me

[@Aerotas]

Yes, however, the RTK corrections do not function without it. You will either have to treat it like a regular non-RTK mission (as you would with a Phantom 4 Pro, with sufficient ground control) or you would have to use CORS station or 3rd party correction data timestamps in order to process the photos PPK.

[@sayedminhaz2430]

Please could you explain me Why need to RTK?

[@Aerotas]

RTK enabled aircraft with offsets to their camera lens location have extremely tight geolocation data (.1'-.2' in most cases), as compared to non-RTK aircraft who's geolocation data can be off by as much as 10' x and y and 50' z. The relatively tight geolocation data on the photos produced by the P4RTK allow for photos to be stitched together with extremely high relative accuracy when compared to non-RTK data. This allows for fewer GCPs to be set for the flight since the model is already very relatively accurate to begin with. The GCPs are used to shift the entire relatively accurate model back to real-world accuracy.

[@kwakutakyi5032]

Is it true the minimum flight time for ppl flights should be 10mins ?

[@mkbarech]

Sir how many mobile stations require when area is 100 acre? Kindly ans

[@Aerotas]

For this workflow, you only need the one D-RTK 2 Mobile Station. This workflow has actually yielded excellent results on sites up to 1000 acres.

[@musansombo7590]

Can it connect to other survey brand base stations such as Trimble 5700?

[@Aerotas]

No, the P4RTK only connects to its own base station. You have the option of acquiring a 4G dongle to connect to a 3rd party network, but we do not recommend this as there are too many variables as play. You can also process PPK by running your 3rd party base in parallel with the P4RTK flight. You would need the rinex files from the drone and other base in order to process, and this takes much longer. We highly recommend using the P4RTK with D-RTK2 Mobile Station for the best, most efficient results.

[@antoniocastagna99]

Vorrei avere un video in italiano del RTK. Grazie

[@shokanthkumar6326]

Great vedio I am fresher to drone processing do you have online courses processing

[@-hi7]

good!

[@marifrahman7021]

👍

[@sonz00]

So many strange porcessing steps in this video... 1) Occupying a known point doesnt work very well? Kinda makes the base pointless..? 2) 7:09 processing with PPK decreases acuracy - How? 3) Due to how Pix4D creates a surface youre introducing errors by doing a block-shift on the entire surface based on one ground control point and getting the entire surface to conform to that. 4) If youre errors are as big as youre showing there then whats the point in using this base/RTK process at all? 5) If youre measuring that many check points with a survey grade RTK GPS, then why not just use 90% of them as ground control points instead and then not bother with the RTK/PPK system at all? You have allot of check points shown in this video This system seems pointless processing it like you have shown here. If it cant be a true RTK stsyem and ocupy a known point then I dont see the bennefit... you would get the same or better results using a non RTK P4P and the same number of check points because you wouldnt be doing a block-shift and you would save allot of money.

[@rcdroneservices3395]

I would also like to know why place base station over known point isn’t reliable.

[@c1c0cc]

@sonz00 perfect questions that shows how this explaned workflow is bad

[@georgefenrichjr.9636]

How much computer power do I need to run PIX4D? I am getting a new PC and want to know how much power / SPECs I need to look for!?