[ANSS-netops] GPS 1024-week rollover --round 2 -- garmin clocks & Webtronics digitizers -- earthworm

[Jon Rusho]

We've seen another instance of the 1024-week rollover, similar to the 
K2/Altus issue discussed last summer.   This time, it was Garmin clocks 
on Webtronics digitizers in the MB(Montana) network.   I changed the 
PsnAdSend Earthworm module to include a similar patch to what I used for 
the K2/Altus k2ew module.   If you're having issues with data being 
timestamped in 2000, it's probably the 1024-week issue.   There is a 
firmware patch for the Garmin clocks that might fix it, but that 
requires physical access which may not always be easy/possible.


Code snippet & context for the change to PsnAdSend.cpp:

/* Make the trace buffer header */
void MakeTraceHeader( SCNL *pSCNL, double tm, DataHeader *hdr )
{
*/* check for 1024 week rollover glitch 2018/2019   jr  */**
**      if (tm > 911143558 &&  tm< 1530403744 )**
**      {**
**        tm += 619315200;   /* add 1024 weeks of seconds */**
**
**      }*

         traceHead2->nsamp = ChanRate; // Number of samples in message
         traceHead2->samprate = ChanRate; // Sample rate; nominal




-- 
===================================
Jon Rusho
Seismic Network Engineer
University of Utah Seismograph Stations

jon at seis.utah.edu
801-585-5523

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