[AndyKrause]

Hello everyone!

Just signed up to the forums to ask a question. I have already read a lot about the topic but wasn't able to find the perfect answer yet. I am looking for a GPS/Magnetometer Combo for the Revolution board, which can be plugged in using one single cable. Currently using the M8N GPS that came with my Revolution board. Not sure if it has a built in magnetometer. Was unable to find any soldering pads. Even if it does have a magnetometer then I am unable to connect it, because I need the Flexiport for the OSD.

The problem arises because the onboard magnetometer on the Revolution has too much interference, causing the artificial horizon in the GCS to tilt and wobble a lot when stationary on the ground. Trying to fly the drone makes it flip instantly. This only happens in INS13 GPS mode. If I turn it to complementary, it works just fine. So I assume this is a compass problem.

Already read about the genuine DJI Naza GPS being supported, as well as clones. Those only need one cable. I read in another thread that the genuine DJI Naza GPS does not supply certain telemetry, like signal strength and which satellites it is connected to.
- Does this cause any alarms in the GCS, which information will I be able to see?
- Do the Naza-compatible clones have the same problem, or do the supply the additional telemetry like the M8N does?
- Are there adapters to turn M8N GPS units into a single-wire solution?
- Any other options for my Revolution board, given that I want to use both GPS and an OSD with telemetry.
- What are possible downsides of cheap Naza clones?

I am located in Germany and have not been able to find a genuine DJI Naza GPS yet. Or at least I am not able to tell which ones are. There is a lot of clones available from Asia. Can somebody provide me with a link to a suitable GPS unit that has been proven reliable in the past?

Current setup:
TBS Discovery, Revolution Board, OPLink Telemetry, Micro MinimOSD, Spektrum PWM Receiver.
Both Mainport (M8N GPS) and Flexiport (OSD telemetry) are in use.
For reference, bought here: https://www.ebay.com/itm/OpenPilot-CC3D-Revolution-Flight-Controller-Combo-mit-M8N-GPS-Transceive/152827851803?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m2749.l2649

Thank you for your help and greetings from Germany,
Andy

[TheOtherCliff]

the genuine DJI Naza GPS does not supply certain telemetry, like signal strength and which satellites it is connected to.
- Does this cause any alarms in the GCS, which information will I be able to see?

It does supply "number of sats used", but not sats seen or sat positions.  It gives what is needed and nothing more.  No alarms.

- Do the Naza-compatible clones have the same problem, or do the supply the additional telemetry like the M8N does?

Authentic and clones send the same data regardless of the chip inside.  The code can't tell them apart.

- Are there adapters to turn M8N GPS units into a single-wire solution?

Yes... at least there were, but they are as expensive as a full clone the last time I checked.  They turned it into a DJI/Naza GPS.

- Any other options for my Revolution board, given that I want to use both GPS and an OSD with telemetry.

OpenPilot Platinum v9 GPS which are not made any more, but some people are making them for about $100

- What are possible downsides of cheap Naza clones?

Clone downside is that some have firmware that corrupts some packets.  It is not something that is noticeable in flight.
Clone upside is that authentic has only a uBlox Neo6 inside, so it only sees USA GPS sats.  Clones usually have Neo8 (M8N) inside so it sees Russia and China sats too.
My purchases say that OCDAY GPS (DJI Naza version) is the best of both worlds.  Neo8 and good firmware.

I ... have not been able to find a genuine DJI Naza GPS yet.

Search your favorite seller site for:
Naza GPS
or similar and you should find both, but beware that you don't want a Phantom internal GPS, you want a Naza that is made to work on anything.  See the authentic GPSs listed below for examples.

Here are authentic DJI Naza GPSs.  All authentic ones look like this, especially look at the connector.
https://www.ebay.com/itm/DJI-NAZA-M-Lite-GPS-Compass-module-only-US-dealer/201557456216
https://www.ebay.com/itm/DJI-GPS-Compass-Module-for-DJI-NAZA-M-Lite-Flight-Control-System/251862698572

Here is a list (authentic and clone) on eBay.com with junk cut out
https://www.ebay.com/sch/i.html?_nkw=%28dji%2C+naza%29+gps+-openpilot+-pixhawk+-apm+-stand+-mount+-cable+-bracket+-mavic+-spark+-tracker+-camera+-support+-holder+-protector+-protection+-cover+-inspire+-walkera+-copper+-6m+-%22phantom+1%22+-%22phantom+2%22+-%22phantom+3%22+-%22phantom+4%22+-folding+-osd+-three

[AndyKrause]

Thank you very much for the detailed and fast answers! Also thanks for the links you provided, very helpful.

Can I assume that all the "black" ones are OCDAY versions? Or do they have to specifically state that name in the description? Price diferences between those modes are quite large, but they all look the same. Is it safe to go for the cheapest offers or I have to pay attention to something else? (besides shipping and country restrictions probably).

[TheOtherCliff]

Assume that if it doesn't say OCDAY that it is not OCDAY.  Also, every OCDAY I have bought has come in a bag labeled OCDAY.

My buying last year showed that most of the black ones (except OCDAY) now come with the buggy (but usable) firmware.  It started out that you could go by the icon stamped on the GPS to know which ones were good, and many shipped good firmware, but then good icons started shipping bad firmware and it seemed that only OCDAY was good firmware in the end.  I've bought about 10, mainly from eBay sellers.

I think that OCDAY has stopped making them and what we see is what is left of original run.  The good firmware seems to be a copy of what rcgroups.com pawelsky wrote and may be disappearing due to copyright issues.
https://www.rcgroups.com/forums/showthread.php?2290346-Naza-v1-v2-Lite-GPS-module-alternative-(using-APM-2-6-GPS-compass-combo)
https://www.rcgroups.com/forums/member.php?u=393936

I recommend you buy the OCDAY for less than USD $30 shipped, rather than the authentic for USD $48.  I can't promise that they will even ship it to you (you can easily get your money back, happened several times the last few times I tried to buy).  I can't promise that it is even the same good firmware.  You know how to test with GCS.  Also, case is slightly transparent on real OCDAY GPS and if you see a white square when looking through bottom you probably have a good one.