[jtrout19]

Hey guys so I finally got my Revo to communicate with the this http://learn.parallax.com/KickStart/28500 gps unit. Sorry the hyperlink button is not working for me. So the data on this guy says that baud rate is 4800. In GCS when on the flight data page the gps light will go green and then go to where it has an X over it and then go green again. It does this over and over again. I am assuming this is because of the slower baud rate. Everything I read about the CC3D says 9600. So my question is this....is there a way to change this in U-Center. Or maybe flash new firmware to the GPS module to support faster baud rate. It also says nothing about UBX. Am I stuck with NMEA or is there a way to get UBX. I am assuming that UBX is better cause that is what is talked about in all the documentation that I read. That is all I got for now. Thanks for the help so far as well guys!

[hwh]

That gps  ( https://www.parallax.com/sites/default/files/downloads/PMB-648-v0.1.pdf ) is based on a SiRFstarIII chipset not a ublox one.  You'd have to find whatever software is used to change the settings of SiRFstarIII gps units.  You'd probably be better off buying a ublox based gps.

You're stuck with the NMEA protocol since a SiRFstar gps doesn't have the ability to send ublox protocol.

If you have a Revo it's probably a revo NOT a cc3d.  In the lower right corner of the gcs screen it probably calls the board a revolution.  If it does then ignore everything you read about cc3d and follow the things that say they're for the revolution (revo) board.

If it is a revo I'd think you might get it to work if you set the gps settings on the config page to 4800 and NMEA protocol.

[jtrout19]

I do have a revo board. It is quite confusing for me trying to find documentation for the revo and not the cc3d. Thank you for the clarification on the GPS module. I might look into getting a u-blox gps. I did get the GPS working but not working like I think it should.

[Mateusz]

I do have a revo board. It is quite confusing for me trying to find documentation for the revo and not the cc3d. Thank you for the clarification on the GPS module. I might look into getting a u-blox gps. I did get the GPS working but not working like I think it should.

CC3D is for racing and can't do full navigation with GPS
Revolution can do full navigation

- You have to get your Revo calibrated and tuned to fly nice in Complementary first (before using any GPS mode) and it write it as first requirement.
- Both Mag and GPS in INS31 mode must be always green when in the field, no jumping to orange, also Mag calibrated outdoors over OPlink and GPS with up to date alamanac.
- Mag must be placed on the mast far from magnetic interference
- Only OP GPS v9 unit is supported in current release, if you want external Mag from other GPS like DJI Naza compatible or GPS unit with I2C connection, this will be supported in next release and is now available in "next" development branch. So you would need to compile LibrePilot yourself if you don't want to wait. Or get OP GPS v9.

Check out wiki https://librepilot.atlassian.net/wiki/display/LPDOC/GPS+setup

When you add GPS and enable INS31, people assume its only GPS sensor added to the stabilization system. That is not true, since more sensors are used in that mode. Which means whatever your problem is, may or may not be related to GPS unit.

[jtrout19]

Thanks again. I will keep this gps unit for now until i get quad flying nicely. Should i make a build log on here to deal with any further technical questions?

[TheOtherCliff]

The last time I tried NMEA protocol (admittedly at least 2 years ago) I got a large slow attitude oscillation that was very visible in the PFD.  When I switched to UBX protocol, the oscillation cleared right up.  I recall that was with a UBX GPS that was configured to output all the correct packets for both NMEA and UBX.  I suspect that the NMEA protocol isn't sending enough good reliable velocity information, and the EKF doesn't like it.  It is possible that the EKF tuning that was done some time (before or after this?) has cleared it up or made it worse.  It is possible that if you know how to tune an EKF you might get NMEA working.  It is possible that NMEA works fine as it is right now.

I can tell you the NMEA packets that LP reads so you can configure the GPS to output them (from NMEA.c):
   {
        .prefix  = "GGA",
        .handler = nmeaProcessGxGGA,
    },
    {
        .prefix  = "VTG",
        .handler = nmeaProcessGxVTG,
    },
    {
        .prefix  = "GSA",
        .handler = nmeaProcessGxGSA,
    },
    {
        .prefix  = "RMC",
        .handler = nmeaProcessGxRMC,
    },
#if !defined(PIOS_GPS_MINIMAL)  /* Revo etc. also looks at these packets */
    {
        .prefix  = "ZDA",
        .handler = nmeaProcessGxZDA,
    },
    {
        .prefix  = "GSV",
        .handler = nmeaProcessGxGSV,
    },
#endif // PIOS_GPS_MINIMAL