New to PPK and on a deadline

Reach Module / M+ / M2 RTK / PPK configuration
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Guys,
after abit of research, I’ve bought the Tuffwing PPK kit for the Phantom 4 Pro. The Tuffwing has a M+ while I use RS2’s in the field for GCP collection.
We are having shocking weather here at the minute, so my window to get the job right is rather small.

I’d like to confirm what I intend to do and ask a few questions:

I’ll use my RS2 as a base with an average time of about 5minutes. I have used this same average position everytime I’ve marked out my GCPs. Will the relatively low accuracy on my base matter?

I’ll be logging GPS, GLONASS, and QZSS. Why can’t I log BEIDOU etc too? Are they L2?

The instructions say to have an update rate of 5hz, Emlid say 1hz. Is this simply a matter of space? to store the files? Wouldn’t higher be better?

I’ve been repeatedly asked for the height of the antenna on the base, but since its averaged, why would it need to ask for that seperately. In my situation, the base is on top of a small tower and it wouldn’t be easy to get a physical height plus the tower is on its own mound, so where do I take a height from?

Which format is better, the newest RINEX?

I’m just abit nervous, something new with limited time and quite large stakes makes the anxiety spike!

What are the other common mistakes people make on PPK drone flights?

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Hi Joe,

I’m glad to help and answer your questions down below :slight_smile:

I see that you’re going to measure volumes in the open pit: Adding Emlid UAV kit or Topodrone to P4PV2

The relative accuracy is enough for volume measurement. The accuracy on the base matters when you need absolute accuracy.

On Reach M+, you can’t choose both GLONASS and BeiDou systems for tracking at the same time.

However, you can switch GLONASS to BeiDou. As you are located in Australia, BeiDou should be more effective than GLONASS in your region.

For the drone flight, it is better to have 5 Hz or 10 Hz, depending on the speed. With the higher rate, you will have a more accurate track.

1 Hz rate is recommended for Base as it is static.

When you’re averaging the base’s position, there is no need to enter the antenna height.

Actually, the ReachView 3 app doesn’t allow you to enter the antenna height when you do the averaging. Can you share the screenshot of the window where you’re asked to do that?

Yes, the newest available RINEX format in Reach M+, V3.03, will be the most reliable solution. Unlike RINEX 2.XX, it can store QZSS, Galileo, and BeiDou raw data. It also has a mixed NAV data file which simplifies post-processing.

You’ve done the right thing by coming to the forum. Other surveyors and our technical support team can help with your questions and save your time!

I guess our guide about mapping with RTK modules can be of great help to you. It covers the most tricky moments in PPK mapping. I also recommend updating both units to the latest firmware version, V27.1, as it contains valuable improvements for PPK mapping.

Good Luck with your project!

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Thank you so much, great reply.
One final big worry:
When I started at this site months ago, I average for 30minutes and use those points every time I fly.
Is it going to be an issue to position a base with a point that is this low accuracy when flying for PPK? I don’t have access to an NTRIP service, although I do regret not doing a PPP at the time.
So, just to be clear:
Will the fact that my base point is not highly accurate affect the information my drone collects?

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So… I went to site and it was a disaster, but not for the reasons I thought it would be.
I had played around with the kit at the office and had a very basic fly but when I put my dronedeploy route in, the drone would reach travel altitude and stop, I am guessing it was picking up the antenna and thought there might be a collision.
I could not turn off obstacle avoidance. I would flick the switch in DJI Go but it would be on next time I went back in. Dronedeploy showed it was on too. The drone flew perfectly with the kit taken off.
Anyone any suggestions on how to turn off obstacle avoidance? I might try sports mode, but the speed makes me nervous!

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No. Locally, the material pile will be very accurately measured but its absolute position on Earth is tied to the averaged position of the base. So unless you need to locate it precisely to compare against external markers, you should be fine.

I’m not personally sure that it was the antenna pole that was getting picked up by the collision avoidance system. It sounds like a flight plan that hangs when it reaches its next step. Have you tried doing a similar flight plan elsewhere?

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I get relative versus absolute and don’t need super absolute.

Rephrasing my question: for PPK, do I need to be over a known point or will a 30minute average for my base station do? I dont have NTRIP etc.

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No, you do not have to be over a known point to do PPK.
But if you need a known point depends on your job. What are you doing with the drone?

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Move the antenna. You need the obstacle avoidance to work anyway…
Do you have some images of your setup? Maybe the community can bring you some additional pointers to further success.

Remember that even if sports mode was the answer, your speed need to be low enough to not introduce motion-blur in the pictures.

In DJI GS Pro the blur is automatically calculated. It should be lower than the gsd value.

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figured it out.
DJI allows it to be turned off, but you need to separately turn it off in the drone deploy app as well, in the planning stage of the flight, otherwise it will turn it back on.

Sometimes it might be necessary to turn it off due to strong sunlight etc, I fly high and away from obstacles, so the risk is very low.

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Just for my personal knowledge, you disabled collision avoidance and then your flight plan worked?

If it’s installed correctly, I guess I know what PPK kit not to buy. :face_with_raised_eyebrow:

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I believe it has something to do with the side sensors detecting the antenna support pole on the Tuffwing Kit, at least that is what a youtube video said.
I have no personal experience with the kit, just going by what the guy said in his video. I have purchase the M2 version from METTA TECHNOLOGIES, but haven’t had a chance to test it yet.

phantom_reach3
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10:55 Disabling side sensors when using PPK Kit

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