NMEA logging findings - just interesting info


Rob Giuliano
 

I am running APRSIS32 2020-10-27 1838 (Development Version) and noticed something different about NMEA logging.

I am running the same uBlox M8 modules I use at work with a different configuration. 
On all units the port I am using sends only NMEA strings (no ubx or RTCM#).
When I use a work GPS with APRSIS32, I get errors in the log, but only when logging is disabled?

Port(NMEA):2020-12-28T15:08:36.452 Processing[66]:$GNRMC,150836.00,A,4209.35008,N,08346.26937,W,0.356,,281220,,,A*7F
WinMain:2020-12-28T15:08:36.477 Logging Disabled
WinMain:2020-12-28T15:08:37.060 Failed To Find PRN 70 in 16 in view (1 8 10 12 15 18 20 21 23 24 25 31 32 44 46 51 )
WinMain:2020-12-28T15:08:37.060 Failed To Find PRN 71 in 16 in view (1 8 10 12 15 18 20 21 23 24 25 31 32 44 46 51 )
WinMain:2020-12-28T15:08:37.060 Failed To Find PRN 73 in 16 in view (1 8 10 12 15 18 20 21 23 24 25 31 32 44 46 51 )
WinMain:2020-12-28T15:08:37.060 Failed To Find PRN 80 in 16 in view (1 8 10 12 15 18 20 21 23 24 25 31 32 44 46 51 )

Digging a little deeper, I find the configuration differences between errors and no errors are:
Key settings with Errors
Numbering used bfor SVs not supported by NMEA:    Strict(no output)
                                                              Main Talker ID:    System dependent
                                                               GSV Talker ID:    GNSS Specific (or Use main Talker ID)

FIX: To fix it, I change the Main Talker ID to GPS(GPS) and GVS Talker ID 'must be' Use main Talker ID to stop reporting errors.

After that, I can change Numbering ... NMEA or  Main Talker ID without errors, until GVS Talker ID gets changed to GNSS Specific, then the erros return and both settings (Main & GSV) must be as specified above to reset it.

Interesting, the GPS information appears to update properly the entire time. 

I am happy to report that APRSIS32 does not restrict decode to $GPxxx strings, but seems to accept $GLxxx, $GNxxx, and $GBxxx.  It goesn't seem to like the Galileo ($GAxxx) strings for the same message types (RMC, GGA, GLL, etc.). 

Thanks for supporting multiple formats as most modern GPS units now seem to send the combined ($GNxxx) messages by default.

Robert Giuliano
KB8RCO

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