[gon]

Hi,

I'm not sure if this is the place for asking this, but:

Before purchasing a Revo board, I want to make sure if I can use this gps (https://learn.adafruit.com/adafruit-ultimate-gps/) with it. From what I've read, it is compatible, but I would love to have some confirmation from you. I'm starting a project about autopilot with an arduino so it is very important to get very accurate GPS Flight Modes.

Thanks so much!

PS: I know that UBX is a better protocol, but I already had this one at home.

[vk4tec]

I have a NMEA adafruit GPS NMEA

Did you get ublox protocol to work with 8M ?

Andrew

[gon]

Hi Andrew,

I'm not sure what your question is. I just want to know if I can use the Adafruit GPS with a Revo. I don't have a 8M nor a Revo board yet (only CC3D) so I didn't use the ublox protocol.

Cheers,

Gonzalo

[Mateusz]

I don't have non-Ublox GPS, but if I go to https://librepilot.atlassian.net/wiki/display/LPDOC/Configure+a+GPS+for+CC3D
It says that you need to enable certain NEMA messages (configure GPS). I am not sure if Revo can do that with other brands, or if the GPS by default will deliver required messages over NEMA protocol.

Also this website says "NMEA is not supported anymore because is less memory efficient, this page only refers to UBlox GPS and UBX protocol."
Given that Revo configures Ublox GPS every power-up I guess the same would need to be done with different brand GPS, so maybe getting it to work is not so stright-forward. By why not to try if you have already such a GPS ?

However, I suggest buying proper Ublox module though, as it comes usually comes with flash for configuration, firmware can be updated and Revo can configure it. Also it often comes with Magnetometer.

[gon]

Well, I wanted to know it before purchasing the Revo board to pay just for one shipment all together.

Regarding the message saying that NMEA is not supported anymore, I thought it refers to the "basic" CC3D boards, not the Revo. So  I guess that Revo can use a NMEA GPS still.

I think I'll try to buy just the Revo and see if it works.

Thanks!

[TheOtherCliff]

Even with NMEA GPSs there is configuration required to make sure that the GPS outputs the needed sentences.  There is generally a way of storing this configuration permanently, but not on some small or inexpensive GPSs.

That said, NMEA (default settings) will probably work for GPS map, but the last time I tried to use NMEA for GPS stabilzed flight, I had oscillations that I did not have with the UBX protocol.  UBX has accurate and less smoothed velocity data.  I imagine that was the cause.  It should probably be retested...

I would recommend a clone DJI/Naza GPS/mag, which are available for around $30 on eBay and elsewhere.  The authentic DJI/Naza GPS has a lot of filtering that slows down the data and causes oscillations.  There is a test/workaround/alpha firmware available that fixes the worst of the DJI/authentic oscillations.  This firmware is not needed for clone DJI GPS.

[gon]

Fine, thanks so much for your answer! I'll try the NMEA GPS and share how it works here and buy the Naza if it doesn't perform.

Thanks!

[gon]

Oh, and what about the serial failure rate? Is it normal?

[TheOtherCliff]

Serial failure rate?  Some OP GPSv9 have some serial failures and can be flashed with fixed firmware.

Generally after it runs and auto configures for less than 30 seconds, it should not have red X health any more.  "Red block" just means "not enough satellites yet".

[gon]

Well, I was asking for the serial failure rate between the CC3D and the Arduino, not with the GPS. Is it normal to get just 1/8 UAVO requests successfully?

[TheOtherCliff]

It should be 100% across a wire.  RF can be spotty though.

Maybe the Arduino isn't fast enough?  Maybe there is a signal voltage level issue (e.g. sending 3.3v and expecting 5v swings at the receiver)?

[gon]

Ops, okay, I'll try to investigate it. Thanks!