GNSS NMEA Input impossible

Cube Autopilot
1

Hello,
I like input NMEA sentence on GPS1 port.

My GNSS send RTK position, it’s a rover who received correction by 4G modem by connection to NTRIP Caster or by radio modem when corrections are transmet by my GNSS Base.

Setup:
GPS_TYPE: 5
GPS_SBP_LOGMASK: -256 (I don’t understand this option and I don’t test -1 or 0)
GPS_GNSS_MODE: 0
GPS_RATE_MS: 200
SERIAL3_PROTOCOL: 5
SERIAL3_BAUD: 38

My GNSS output data by DB9 RS232 femelle , I build a cable with DB9 male to GPS1 connector, Pin2 DB9 to Pin2 GPS1, Pin3 DB9 to Pin3 GPS1 and Pin5 DB9 to Pin8 GPS1. I test another cable, Pin2 DB9 to Pin3 GPS1, Pin3 DB9 to Pin2 GPS1 and Pin5 DB9 to Pin8 GPS1.

Has anyone made this kind of connection before? I can find no information about it!
Is there a documentation that details the frames and parameters for using the NMEA data of a GNSS RTK for navigation(Boats) and the log of the positions of a measurement (sonar in my case).

Thanks
Ludovic

2

rs232 is wrong voltage level
Cube requires ttl serial, not rs232 serial, you need a converter

1 Like
3

Thanks a lot for the information, I basically thought that just put RX on TX and TX on RX. I’ll order a converter and go back on the operation.
A simple SERIAL to USB converter don’t do that?
Sorry for my English, I’m French.

4

Hello,
I come back for explain my solution.
I have order a low cost converter by Amazon, but it’s not work after some test.
Finaly I buy a Sparfun converter PRT-08780, and it’s OK I can use my Survey GNSS!
Thanks

5

I am using rtk since some weeks. Tersus GNSS . I can see RTK FIX on MP screen . Do you Change any parameters of pixhawk for high accuracy flight ?

6

Hello,
For the moment I can’t doing test in France, my project is a boat.
On my boat I have a rover GNSS who receive correction by his radio from a base install on know point.

Rover send NMEA GGA, RMC and VTG at 5Hz,115200 baud to Pixhawk. I don’t know if RMC and VTG are use by Pixhawk, no docs for explain what NMEA message are importante for navigation.

Without navigation test I have juste change EK2_ALT_SOURCE at 2 for use altitude from GNSS and no barometer, it’s important for my project to have ellipsoid height for referencing my bathymetrie on french system.

After first test, if I change parameter I come back here.

7

what brand is your gps, nmea is a very bad protocol, as it doesn’t contain alot of information the autopilot needs

8

For me it’s a survey GNSS, T300+ by Comnav technology.
Now, with NMEA it’s OK but I have problem for setup position Offset for my GNSS, IMU and Sonar.
Can you help me with this draw?

Equip_position
Equip_position1123×794 72.2 KB

What are the good offset setup?

Thanks

9

the comnav binary protocol is supported. assuming it hasn’t changed.
it is the same as novatel. set GPS_TYPE to 15 aka NOVA

10

I think it’s an error, it’s not ComNav marine but Comnav technology (SinoGNSS compagny) http://www.comnavtech.com/

11

yes comnavtech = nova

12

@Michael_Oborne

I am connecting a Novatel OEM7 729 to the orange cube. You mentioned nova messages above. do you know what the configuration may be on the Novatel side to send these message? bestpos? PSRvel?

I have yet to make NMEA work (GPS TYPE 5).

Thanks.

~John

13

the driver should try autoconfigure the gps, the issue could be around the port used.

however messages used are

bestvel
bestpos
psrdop

as per here