RTK for Nikon mirrorless/D-SLR

Reach Module / M+ / M2 RTK / PPK configuration
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Dear all,

I find myself often photographing archaeological digs or while walking in cities. I am looking for a solution to log coordinates for every position where I take a photograph (with a Nikon Z7II). Ideally, these coordinates should be 10 cm (or better) accurate when I photograph in situations without severe multipath effects).

I think that the M2 or M+ would be useful to me, but I understand that I also would need an adaptor to connect the M2/M+ to the hot shoe. Does this work with every camera hot shoe (so any of my Nikon D-SLRs and mirrorless cameras)?

Would I also need an antenna for this solution? Ideally, all should fit on top of my camera or on a cage I built around it. What antenna would you advise? Would the Tallysman GNSS antenna work for my purpose or would I need the Multi-band GNSS antenna? What would be the difference between them?

Finally, can I connect the M+/M2 to my phone over WLAN to get the RTK correction signal? I am living in Vienna, and I have free access to the EPOSA correction signal. If not, how would I otherwise get an RTK correction (PPK is too cumbersome for me and when I walk around, it is impossible for me to set up a base station)?

With RTK correction coming over my phone, is there any reason to use the M2 over the M+?

Sorry for all the questions. I appreciate any help or insights!

Geert

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Hi Geert,

Welcome to the community forum!

I can get what you’re saying about PPK being cumbersome when it comes to creating the photometric: you have to wait to get all the pieces together. Still, I’m about to give you a bit of the bitter truth here: if you want to work with Reach M2 and match your photos with the position, it has to be PPK. No pain no gain, so to say :sweat_smile:

I’ll explain how it works. You connect Reach to your camera via the hot-shoe adapter. When your camera takes a photo, Reach records a time-mark to the raw data log. To know the actual position of that time-mark, you need to post-process the data. Then you can geotag your pictures.

This process may seem tricky with RTKLib, for example. However, we’ve come up with Emlid Studio: our own post-processing tool. There, post-processing and geotagging are easy and comprehensible. We have tutorials to prove it:

  • PPK: how to use the PPK function in Emlid Studio for kinematic and static data post-processing

  • Drone Data PPK: the process of geotagging of the images in Emlid Studio that are used for further mapping in photogrammetry software

So maybe you can consider PPK as the method for you. Alternatively, you can just collect the points in the project in ReachView 3. However, in this method, there’s no way to easily bind the coordinate with the photo.

I’ll answer your questions below.

As long as the camera has the hot shoe, it’s good to go. What we have to know with it is the moment the shatter falls.

Sure, to work with the M2 receiver, you will need an external antenna. You can choose any antenna as long as it fits the electrical requirements for the receiver and tracks the same sats.

Please note that with the multi-band M2 you need to use the multi-band antenna. This ensures the receiver sees all satellites it’s capable of. This way, you get all the perks of using the multi-band system.

You can connect your Reach to the phone’s hotspot, yes. That’s if your phone is always near the receiver. Otherwise, you can use the LTE modems through the USB-OTG.

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Dear Polina, thank you so much for your valuable information.

However, I still have one burning question if I may: you say that PPK is the way to go, but that it is also possible to have RTK when my phone is a hotspot. Is the latter than not easier and quicker?

If I can configure the M+/M2 to get the NTRIP RTK correction data via WLAN <> Hotspot connection, would that not be more convenient than using the PPK route?

Many thanks again for your insights! Geert

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Geert,

Anytime :+1:

It’s certainly quicker, as you get the result straight away.

Still, I had the impression that you’d like to tie your coordinates with the photos you’re taking. This procedure is called geotagging: it literally writes the coordinates to the photo’s info.

If that’s what you’re aiming it, that it can be done in post-processing only, no way to do it in RTK. The reason for it is simple: we don’t record the coordinate of the photo, we record the time when the photo was made.

If you’re okay with just an array of points and then photos in a separate folder, then, of course, working in RTK with the Survey tool is more than fine.

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Hi Polina,

yes, geotagging is what I am after. However, geotagging does not mean that the coordinates have to be written directly inside the photo’s Exif header or in a sidecar XMP file. In many workflows, this is done after the image acquisition by syncing a log file with timestamps to the photographs.

From your explanation, it seems that this can indeed be done with the M2. I could log the RTK data stream and when back home, extract the position of the photo from the log and then use that info to embed in the image or the sidecar file.

Many thanks! You helped me a lot, although I might have expressed myself badly in the beginning. I simply want to avoid a workflow in which I must wait for a week to get access to the PPK data and then process the coordinates. I take photographs at least 2-3 times per week, so the only thing that works for me is if I can directly process the images.

One more thing that is on my mind: how is the M2 powered?

Again thanks for your response! Best regards from Vienna! Geert

7

Hi Geert,

Oh, I see. I must be a bit persistent about working in PPK :sweat_smile: Let me explain.

You could log the position data in real-time. However, the question is: how do you understand which position belongs to each photo? The time-mark from Reach is written to the raw data log, not in the position log. So it means that you won’t see them while looking through the position log.

Time-mark doesn’t assign the position, it only confirms the time when the photo was taken. It means that most likely, you won’t find the time in the position log that would belong to the time mark, as there is no way to synchronize them in real-time. The position log contains measurements at a frequency of the GNSS rate you set previously: by default, it’s 5 measurements per second.

If you need to know the position precisely, you need PPK in such setup: when you calculate the position, you know it for all the time of the survey. So you can find any position at any time, including the time of the time-mark.

I assume you can hack the system and average the position to be proximately around the time you took the photo. Still, it won’t be accurate, strictly speaking.

You need some external power supply to power Reach M2. For example, the power bank or a battery will do. Also, in our First Setup we covered the most popular ways to power up Reach: through wall adapter, power bank, or USB port of a computer.

Pay attention to the power source’s specs, though. Reach’s peak current consumption is 3A. You can check the electrical requirements in our docs to find out more about them.

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Though this deck is quite old, a lot of Nikon cams still carry the 9-pin port mentioned below: https://missions.capnhq.gov/Imaging_Information/Aircrew%20-%20NikonD200_With_A_GPS.pdf

If this still works, you can do geotagging without post processing.

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Thank you again Polina. Ok, I understand now that it won’t be possible. A pity. Bets regards! Geert

1 Like
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Dear wizprod,

thanks for the suggestion. This is indeed a solution I have relied much on in the past. However, current Nikon cameras do not have this port anymore, but use another port for geotagging the photos.

The most known brand that makes such devices is Solmeta. I have all their geotag solutions, but they do not use any differential correction of the satellite signal, which means that positions are 2 m accurate at best.

That is why I look for a compact, easy and affordable solution that is 10 cm accurate (so via real-time signal correction or via post-processing).
Cheers!

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