Hey,
for a project I am working on (GitHub - rvt/openace: Conspicuity device with support for ADS-L, OGN, FLARM for General Aviation) I am using a waveshare module with the L76B GNSS. One issue with this module is that the PPS R0 bridge might be hard to solder for some people due to it’s small size, and thus I want to provide Software PPS mode based on RMC timing using $PMTK255,1
However, what I am seeing is that Most of the time I see the advertised timing between 240 and 260ms. But sometimes it jumps back 150ms..190ms and I am measuring this both with a Scoop and in Software.
All I can make it relate tp is the number of satellites it’s receiving, but I find that strange that it differers so greatly.
Any Reason why this could happen or what I am missing?
The GPS: $PMTK705,AXN_5.1.6_3333_18060500,0001,Quectel-L76B,1.0*53
I am issuing the following configurations
$PMTK251,115200
$PMTK220,1000
$PMTK255,1
$PMTK353,1,1,1,0,0
$PMTK313,1
$PMTK301,2
$PMTK314,0,1,0,1,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0
$PMTK285,4,50
$PMTK225,0
$PMTK286,1
For each command I am confirming that the command was received by waiting for the response code, the CRC is added in a piece of code and thus not shown in the above example.
Cheers,
Ries