GPS ublox neo6m - NMEA or UBLOX protocol better?

[Hamburger]

from what I understand those gps modules support a range of protocols. Accidentally, mine came preconfigured for NMEA.
To change serial speed from 115200 to 57600 I went and installed ucenter on a win-pc. So I am all set to configure the module.
Now i am wondering whether switching to another protocol (ublox) would be benefitial? If so, why?

[Leo]

From what I understand is the uBlox protocol is binary and has fewer bytes per message compared to NMEA.
I've also read that the uBlox protocol gives 3D velocity for inertial correction of attitude, whereas the NMEA protocol gives only 2D velocity.

I'm using uBlox as it seems to have less restrictions in MW.

I changed mine to 38400 at 5Hz.

Leo

[QuadBow]

@Hamburger

I agree with the comment of Leo and recommend to select UBLOX protocol only in order to avoid further CPU burden for the controller due to additional NMEA messages, which are not necessary. I run my UBLOX GPS also at 38400 and 5Hz.

I faced an issue with I2C-GPS-NAV running UBLOX (https://code.google.com/p/i2c-gps-nav/issues/list number) which requires a patch (look at issue number 6).
For my Mega 2560 everthing works fine without any patch required.

[Hamburger]

I changed mine to 38400 at 5Hz.

do you change this via ucenter or the initialization code from inside MWii?
(I have just changed to 57600 via ucenter to avoid serial glitches)
Is 5Hz default?

thanks for the help/

[Leo]

I changed to 5Hz (200ms) in ucenter (default is 1Hz) and I changed to 38400 in ucenter and in MW.

Code: Select all

// avoid using 115200 baud because with 16MHz arduino the 115200 baudrate have more than 2% speed error (57600 have 0.8% error)
#define GPS_BAUD   38400       // GPS_BAUD will override SERIALx_COM_SPEED for the selected port

(I have just changed to 57600 via ucenter to avoid serial glitches)

I might do the same.

Leo

[QuadBow]

do you change this via ucenter or the initialization code from inside MWii?
(I have just changed to 57600 via ucenter to avoid serial glitches)
Is 5Hz default?

You can change it from u-center, but there are a lot of cheap GPS UBLOC devices without internal EEPROM, so they will forget your configuration and start with 1Hz and NMEA.

Therefore, multiwii reconfigures the device at every startup due to the configuration you selected with the definition GPS_BAUD in the file config.h.
Furthermore, the rate is selected by multiwii to 5Hz, there is no need to change it, since the GPS device does not provide a higher frequency.
The NMEA message sets (which are not necessary) are disabled by multiwii, too.

[Hamburger]

Cool.
So MWii does the right thing and I am all set.
Thanks for the clarification

[Leo]

Well, I gave it a try. I reset my Ublox GPS to default values via u-center.

I activated

#define GPS_BAUD 57600 // GPS_BAUD will override SERIALx_COM_SPEED for the selected port

and

#define UBLOX

in the config.h file.

It seems to be looking good. An actual flight test should confirm proper functions.

[Hamburger]

Just back from the field, I can confirm it works.