PPK Kit Causing loss of GPS

Hi all,
I purchased a Tuffwing PPK kit for my Phantom 4 drone, it seems to work well, but today I had an issue where I could not keep enough satellites on the drone to continue the mission, I kept getting:
“Mission interrupted please check drone control”.
The number of satellites dropped to 7 or 8 mid flight in the most open paddock available with no interference. (map here (Google Maps) ). I had it return 5 times, trying everything, turning all on and off, usb out and it etc. No luck.
I took the kit off and finally got it to fly with no issues, which is unfortunate as the kit was going to really help today. Any ideas why this kit would kill so many satellites and is there any thing I can do? Crazy that there are so few satellites with such open areas (max I got was 13 with kit off)… Could my drone GPS be malfunctioning?
Joe

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If you are using Emlid equipment I would suggest going to that form instead.

I can’t really help as I have never had this problem but I would look at the receiver’s status and make sure all of the constellations that you have selected are in good order.

I’m using the Emlid reach M+ but the drone GPS is the problem, the kit seems to reduce the number of satellites available and I was wondering what a typical number of satellites is for people when using a P4V2 - at full strength I am only getting 15 max, which seems quite low. I’m wondering if there is an issue with my drones GPS unit as the kit has been sold numerous times and works, so it must be my drones reception.

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I would say that 15-16 is pretty typical. The Emlid equipment will always show more satellites (22-23) because it uses more constellations than what the drone does. What symptoms are you seeing that makes you think a lack of satellites is affecting anything?

Michael,
think you are on the wrong track here.
My drone’s GPS is only getting 8-9 with the kit on, the Reach M wouldnt be a problem.
My question is, on average, how many satellites does your DJI pickup usually?
Joe

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The drone usually has 15 and the Emlid equipment usually shows 50% more than whatever the drone shows.

I would like to know if you have a resolution to this issue. I am about to hit the Buy Now button on either the Metta PPK kit or the Tuffwing Snap PPK kit for my Phantom 4 Pro V2.0. And Michael do you have a preference on either system…one over the other? Thanks and Happy New Year.

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Being that you have the M+ and not the M2 I would go with the Tuffwing kit. The Metta kit is built for the M2 which uses a different antenna. I assume you already have the Tallysman antenna for the M+?

Emlid Tallysman

Actually I currently have an M2 with a survey antenna that I use for ground control when needed. So I might be better off with the Metta?

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If you have an M2 then I agree the Metta is the better option. You can modify a Tuffwing kit to use an M2 but there’s no need since the Metta kit came out. I haven’t used that kit specifically but I can see that it is all the same basic components and what it’s doing isn’t rocket science. You’ll just get a more robust feed with the M2 which can alleviate some frustrations which can happen with single frequency.

I appreciate the feedback Michael. Happy New Year!

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You would be much better off using an actual Phantom 4 Pro RTK and or use GCPs for GPS corrections. I’ve heard the same issue from others that have purchased 3 rd Party kits.

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Of course an RTK drone would be great but you’d also be $4,000 poorer. We have flown Tuffwing kits for over 3 years now and have never had an issue with any of the native GPS. Also it’s not recommended to run GCP’s with RTK unless you are absolutely sure that your processing algorithm is correctly balanced between the RTK geotags and the GCP coordinates. I haven’t found a piece of software yet that does it correctly. You’re better off correcting the alignment and other software.

This topic would be better researched on the Emlid form. There are people much more knowledgeable about GNSS and in particular this equipment.

Using GCPs with RTK is a great combination. It’s not rocket science as long as you use quality processing software. Global Mapper does a wonderful job and so does Propeller.

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I’d recommend that you compare it by doing a field verification stakeout and testing against a PPK dataset with just a calibration from checkpoints. Obviously the data is going to be spot on but look for grade breaks and areas at point furthest from the GCP’s. I know this has been happening with Pix4D and DroneDeploy alike. Metashape was much better but we had to tweak the camera calibration and weight of the GCP’s. I wish their was a way to use GCP’s for horizontal only and do they vertical calibrations in actual point cloud editing software. Most of the time we shoot off the RTK network but there are some time where site local coordinates force us to localize to match them. I think we probably have different use cases and workflows but that has nothing to do with this post.

I typically use Metashape with Propeller GCPs. I may need to evaluate my workflow based on your comments.
Agreed wrong forum but ultimately helpful to me. Thank you.

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The main problem we have had is that the GCP’s are creating little bubbles of accuracy but fighting the geotags of the images surrounding them which sort of defeats the purpose of RTK geotags. The worst I have seen though is on roadway maps where it actually tilted the model to one side along the run. The was really no good GCP’s in close enough proximity to the roadway so we would of had to overfly a full block on each side to have a chance. This may be a use-case where just the RTK/PPK is the only method currently available. Feel free to PM me. I’d love to stay connected and maybe learn a little about your workflow. It would probably help me just as much.