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Users => Vehicles - MultiRotors => Topic started by: timelapse21 on January 17, 2017, 07:53:38 pm

Title: Best GPS for position hold
Post by: timelapse21 on January 17, 2017, 07:53:38 pm
Hi all:

I have a revolution board and have been finding that with my ublox neo 6m the gps position hold is not very accurate. It drifts pretty substantially, and I dont exactly feel safe taking my hands off the controls.

What GPS would you recommend to remedy this issue? I have heard that the naza gps is a good bet but is there a difference between the naza m-lite gps and naza m v2 gps? And also does the naza gps have a built in external compass?

Thanks,
Tim
Title: Re: Best GPS for position hold
Post by: DocHardinger on January 17, 2017, 08:04:46 pm
I use ublox neo m8n gps which is very stable in pos hold but you need to ports, one for mag and the other for gps...somewhere in this forum theothercliff posted some links to the original naza m lite gps which is also very stable and you only need one port...

I think it was this one:
http://www.ebay.com/itm/DJI-Naza-M-Lite-GPS-Module-with-GPS-Bracket-for-RC-Quadcopter-Multi-rotor-G2T4-/131988064582
Title: Re: Best GPS for position hold
Post by: timelapse21 on January 17, 2017, 08:16:06 pm
Thanks for the link - but it says it doesnt ship to canada :(
Title: Re: Best GPS for position hold
Post by: hwh on January 17, 2017, 08:22:03 pm
The auction he posted is for one of the recommended gps units.  It was one of the ones used in programming and testing the Naza GPS support.  You can get that model from a lot of suppliers.

As for the difference between the M and M-lite we don't really know.  All the testing was done with the lite one or a clone.   Cliff found that the real M-lite performed better than the clone.  I don't think any of the developers has the full M one so we can't be sure if it works better (or at all) than the lite one.  All the Naza GPS units have an external mag in them and only use one port on the revo.
Title: Re: Best GPS for position hold
Post by: DocHardinger on January 17, 2017, 08:24:10 pm
Maybe wait for theothercliff to answer...he did the coding for the dji gps and maybe got some more links :-)
By the way im also interested what the difference between naza lite gps and naza gps v2 is...i think naza lite gps uses ublox m8n gps module with a chip inside which combines data of gps and mag. Thats why you just need one port...i also think that naza m lite and naza m v2 are just the flightcontrollers...dont know if they really sell a better v2 gps..maybe in v2 gps there are an extra chip for calculations or whatever...hope theothercliff will bring light into this ;-)
Title: Re: Best GPS for position hold
Post by: timelapse21 on January 17, 2017, 08:29:22 pm
Looking at some dissection videos of Naza gps versions - here are the links.

https://www.youtube.com/watch?v=p7q_2ku_yck
https://www.youtube.com/watch?v=04PB1R4j7y4

It appears they both have the same Ublox Neo 6Q???  (You can see the writing on the gps if you make it full screen at 0:48 in the first one.

Never heard of it :)

Any info on whether that is more accurate than an m8n?

This is becoming interesting...

Tim
Title: Re: Best GPS for position hold
Post by: hwh on January 17, 2017, 08:40:13 pm
...Ublox Neo 6Q... Never heard of it :)

Any info on whether that is more accurate than an m8n?
...

It's just an older module, it's not really more or less accurate.  It doesn't support the newer positioning satellite constellations, just the US GPS one.  On the other hand, some testing seems to indicate that it's less prone to some errors that the newer multi-constellation modules have.   They seem to have occasional jumps to a different position that the 6 series didn't seem to have.
Title: Re: Best GPS for position hold
Post by: DocHardinger on January 17, 2017, 08:42:26 pm
Neo-6m has a chrystal oscilator and 6q has a tcxo oscilator  :P
Now we are wiser...
And i think with neo m8n you can use russian, chinese and european  satellites( GPS/QZSS, GLONASS, BeiDou) too...
Title: Re: Best GPS for position hold
Post by: timelapse21 on January 17, 2017, 09:08:18 pm
And does the naza have a built in compass?

Sent from my HTC One M9 using Tapatalk

Title: Re: Best GPS for position hold
Post by: DocHardinger on January 17, 2017, 09:11:36 pm
Yes sir if you mean the naza m lite gps module
Title: Re: Best GPS for position hold
Post by: timelapse21 on January 17, 2017, 10:15:43 pm
Yes sir if you mean the naza m lite gps module
Yeah, that is what I meant. Thanks for the info everyone

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Title: Re: Best GPS for position hold
Post by: DocHardinger on January 17, 2017, 10:33:10 pm
But be sure to get a original naza gps...like this one i posted before...ebay...

Edit: ive found cliffs post he did some research on naza gps:
https://forum.librepilot.org/index.php?topic=2237.0
Title: Re: Best GPS for position hold
Post by: timelapse21 on January 18, 2017, 01:36:49 pm
What about some of these? https://www.amazon.ca/gp/aw/s/ref=nb_sb_noss?k=m8n+gps I see a few m8n GPS for naza, do you think that would work well?

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Title: Re: Best GPS for position hold
Post by: DocHardinger on January 18, 2017, 06:19:47 pm
Mine looks like this one from ebay:
http://www.ebay.de/itm/351731681219?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT
Title: Re: Best GPS for position hold
Post by: TheOtherCliff on January 19, 2017, 03:52:45 am
If it says M8N it is a clone.  If it doesn't look exactly like a real DJI/Naza GPS it is a clone.  The clone that I bought has some issues, but it works well enough to use, assuming that you can take control if it does something bad (my clone did something bad once in hours of flight testing).

I buy the authentic ones.  They are about USD $10 more expensive than the clones.
Title: Re: Best GPS for position hold
Post by: TheOtherCliff on January 19, 2017, 03:54:10 am
It's my understanding the the GPS that comes with the DJI Naza Lite is the same as the GPS that comes with the DJI Naza V2.

The GPS inside the DJI Naza GPS is a uBLox Neo 6.  It only tracks USA GPS satellites, not other country versions of these satellites.  Newer (non DJI/Naza) GPS units use more satellites. so the clone GPSs will track more satellites than the authentic ones.  I think i've found that newer GPS units have more problems with more/worse sudden "jumps" though.

All the DJI GPSs have mags and only need one port, that is why they are desirable.
Title: Re: Best GPS for position hold
Post by: lucapif on January 23, 2017, 09:40:04 am
And 'normal gps Naza original and Revolution
Skyview is empty?
Title: Re: Best GPS for position hold
Post by: f5soh on January 23, 2017, 03:18:08 pm
This is the normal behavior.
Naza GPS do not send constellation information to populate the skyview.
Title: Re: Best GPS for position hold
Post by: lucapif on January 23, 2017, 11:01:01 pm
Thank you  f5soh
Luca