Using 2x Reach M1 as Ground Control Points

I saw a product that was ground control points with inbuilt RTK GPS. I’d like to work towards something similar, starting with just two Reach M1 units. My idea is to have the units sitting directly on top of the GCP markers (a big black and white tile). One unit would stay on the GCP for the entire job. The other would roam to several other GCP tiles. I’m doing this becasue I don’t have a drone to which I can retrofit an RTK GPS As far as I know, I can’t do that with the Phantom 4 Pro. In any case I’d need a lot more gear to do that. I’m rather new to this so forgive me if I ask some silly questions-

Could I do this with 2 x Reach M1? One as a base on the tile and one roving to other tiles.
I rather like the idea of working towards having 5 of these with the units permanently attached like Propellor’s very expensive GCPs with built in RTK GOS.
Should I instead put the M1s on tripods?
Do I need the GNSS antennas?
How accurate would the results be?

I assume I could use one unit if I left it there for hours and went through the PPK process, but that isn’t an option. Thanks for your help.

I assume you’re talking about the M+ model? The enclosure will work but you would have to swap out antennas for the drone for the L1 only signal.

Hi @skyspec,

Welcome to our forum!

You can use two Reach M+ as a base and rover to collect GCP points. We have a guide on how to place GCP’s in RTK mode with Reach devices.

To work properly, Reach M+ also requires GNSS antenna, power, and LoRa antenna for RTK. GNSS antenna should be placed under a clear sky view 30 degrees above the horizon, so a tripod will be helpful.

You can place one unit as a base station over a known point or obtain point coordinates via PPK with CORS or PPP. But please note that accuracy of Reach M+ in PPP is 30 centimeters because it’s a single-band device. Other GCP’s can be collected with the second Reach in RTK or PPK modes. Horizontal accuracy of these points will be 7 mm + 1 ppm and vertical - 14 mm + 2 ppm.

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Hi Anna

Thanks for your reply. OK, I wasn’t aware it was single band. Thank you.


You may have already seen, but just in case, we have Reach M2. It’s multi-band device and can be used in your case.

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