Advice on minimizing the number of NMEA messages on the LG290P UART1 output

GPS/GNSS
1

Hi All,

I would greatly appreciate advice on how to minimize the number of NMEA messages on the Sparkfun LG290P RTK Receiver module UART1 output so as not to overwhelm the serial message parser frontend in my Python program.

Presently the QGNSS app Console repeatedly shows the following NMEA message stream:

  • GNRMC
  • GNGLL
  • GNVTG
  • GNGGA

The above four NMEA messages repeat for a while and then after a final GNVTG message the following NMEA messages appear:

  • GNGSA
  • GPGSV
  • GLGSV
  • GAGSV
  • GBGSV
  • GQGSV
  • GIGSV
  • GNGGA

Then begins sending the four NMEA messages shown above again until repeating the eight NMEA messages just shown. I assume that the eight NMEA messages shown above concern information about the various GPS satellite formations and are not germane to the latitude and longitude information provided by the first four NMEA messages especially the GNRMC message which my NMEA serial message parser is looking for?

Therefore, can I use the following PQTM message to disable the eight superfluous messages: $PQTMCFGMSGRATE,W,Port ID,Msg ID,Rate*Checksum

Example: $PQTMCFGMSGRATE,W,1,GGA,0*Checksum

Or is it even possible to turn off the eight superfluous NMEA messages?

Advice please!

Regards,

TCIII

2

This is what I normally use for the LG290P:

NMEA:Rate
RMC: 1 (optional, dynamics)
GGA: 1 (required)
GSV: 1 (optional, if you want to display metrics for each bird)
GST: 1 (I will use a less frequent Rate if that's ever an option)

Plus, Turn OFF any constellations that don’t provide a benefit to you.

1 Like
3

Of course,I just finished arguing with qgnss and luckily I’m back at 1.10!
I had to disable all RTCMs and enable nmeas…
I’ve made a few mistakes and I apologize for not correcting them yet…
however just put 0 instead of 1…
$PQTMCFGMSGRATE,W,GGA,1*0A
$PQTMCFGMSGRATE,W,RMC,1*17
$PQTMCFGMSGRATE,W,GSV,1*09
$PQTMCFGMSGRATE,W,GSA,1*1E
$PQTMCFGMSGRATE,W,VTG,1*0E
$PQTMCFGMSGRATE,W,GLL,1*0C
$PQTMCFGMSGRATE,W,GBS,1*1D
$PQTMCFGMSGRATE,W,GNS,1*11
$PQTMCFGMSGRATE,W,GST,1*0B
$PQTMCFGMSGRATE,W,ZDA,1*04
and send them to checksums…

so for disable rtcm’s on current uart

$PQTMCFGMSGRATE,W,RTCM3-1005,0*58
$PQTMCFGMSGRATE,W,RTCM3-1006,0*5A
$PQTMCFGMSGRATE,W,RTCM3-1019,0*54
$PQTMCFGMSGRATE,W,RTCM3-1020,0*5E
$PQTMCFGMSGRATE,W,RTCM3-1041,0*59
$PQTMCFGMSGRATE,W,RTCM3-1042,0*5A
$PQTMCFGMSGRATE,W,RTCM3-1044,0*5C
$PQTMCFGMSGRATE,W,RTCM3-1046,0*5F
$PQTMCFGMSGRATE,W,RTCM3-107X,0,0*2E
$PQTMCFGMSGRATE,W,RTCM3-108X,0,0*21
$PQTMCFGMSGRATE,W,RTCM3-109X,0,0*20
$PQTMCFGMSGRATE,W,RTCM3-112X,0,0*2A

$PQTMCFGMSGRATE,W,RTCM3-113X,0,0*2B

and nmea

$PQTMCFGMSGRATE,W,GSV,0*08
$PQTMCFGMSGRATE,W,GSA,0*1F
$PQTMCFGMSGRATE,W,VTG,0*0F
$PQTMCFGMSGRATE,W,GLL,0*0D
$PQTMCFGMSGRATE,W,GBS,0*1C
$PQTMCFGMSGRATE,W,GNS,0*10
$PQTMCFGMSGRATE,W,GST,0*0A
$PQTMCFGMSGRATE,W,ZDA,0*15

2 Likes
4

@bamarcant

Thanks for the quick response, much appreciated.

This is exactly what I was looking for.

Additionally, I have found AI answers for this issue to have incorrect Checksums and have found this link to be correct and in agreement with your Checksums: NMEA checksums

Regards,

TCIII

1 Like
5

Hi @TCIII ,

QGNSS will calculate the checksums for you - if you select Advance - Checksum Type - NMEA:

image
image672×237 6.89 KB

Paste $PQTMCFGMSGRATE,W,ZDA,0* and it calculates the 15 for you…

Best wishes,
Paul

1 Like
6

Matter of habit but 1.10 was better done…

immagine
immagine1366×739 63.2 KB

1 Like
7

@bamarcant

Yes, I noticed that function in the Com Tools.

Regards,

TCIII