Skipp

  • *
  • 11
GPS without Mag
« on: February 20, 2017, 11:22:09 pm »
Hi,

is it possible to use a GPS without a Mag for fixed wing. For fixed wing a Mag is not needed because it's always moving.

If yes, how can I disable the Mag and use only GPS.

 Board is a Revo Mini with 16.09

Thanks
Steve

Re: GPS without Mag
« Reply #1 on: February 21, 2017, 04:55:37 am »
Yes.  The problem is that LP doesn't really support that.  It uses the "fixed wing constraint" and assumes that whatever direction the GPS says it is traveling is also the direction it is pointing.  There are problems with strong wind though.  It can be pointing north and there be a strong wind from the northeast so it is actually traveling west.

Maybe you can use the Revo onboard mag?  With fixed wing it is sometimes easier to get the FC farther away from the high current wiring.

Skipp

  • *
  • 11
Re: GPS without Mag
« Reply #2 on: February 21, 2017, 08:03:36 am »
Yes means it is possible? Can you let me know how to do? I can´t use the revo´s onboard mag. It´s for a X1 Skywalker and I only have tiny litte space for FC, ESC and UBEC.
But I will not use autonomous Flightmodes. I only want to see some GPS-Data in the OSD. But I only can use a small and light weight GPS without a Mag.

If you have any other idea to get this it´s highly welcome.

Thank you
Steve
« Last Edit: February 21, 2017, 08:44:21 am by Skipp »

Re: GPS without Mag
« Reply #3 on: February 21, 2017, 09:35:33 am »
That can be done and is supported by LP.

Either you can use an OSD that allows GPS to be connected directly to it and the Revo will not even know there is a GPS, or the GPS will be connected to the Revo and the OSD will also be connected to the Revo and get GPS data from the Revo.  The second way allows you to see the GPS data in the telemetry too.

Enable the GPS in Hardware.  Leave "Attitude -> Settings -> Attitude Estimation Algorithm" at the default of "Basic (Complementary)".  You should see the GPS health red (ok but no data) then orange (some satellites) then green as the GPS finds satellites, not an X.

You will be setting it up as if it were a CC3D, but unlike the CC3D you can use the small GPS that doesn't remember settings since you have a Revo to do autoconfig (the default settings should work fine), and thus you don't have to do any of that ublox ucenter GPS configuration talked about in the wiki.

There are several different ways to set it up.  This thread is one I bookmarked for my own information.  :)
https://forum.librepilot.org/index.php?topic=2999.msg20874#msg20874

And search the wiki for things like minimosd, minoposd, mwosd, mavlink, msp
https://librepilot.atlassian.net/wiki/display/LPDOC/

Skipp

  • *
  • 11
Re: GPS without Mag
« Reply #4 on: February 21, 2017, 10:10:55 pm »
Thank you for your great support! I will try so.