[time-nuts] Additional leap second results

Keith Loiselle keith.loiselle at gmail.com
Thu Jul 2 19:29:47 EDT 2015


Guys,

We tested the recent firmware updates for the JLT products, and they
correctly output the 23:59:60 time stamp, this firmware even outputs the
correct leapsecond timing if GPS signals are totally lost and the GPSDO is
in GPS-holdover mode during the actual event. We recorded a video of the
leap second event from the LCD screen of our new Low Noise Rubidium GSPDO.
You can see it here, showing GPS time, UTC time, and the total number of
leapseconds added:

    https://vimeo.com/132296287

This LN Rb GPSDO uses the new Ublox M8T with multi-GNSS support.  It worked
as expected with GPS reception, but with GLONASS-only reception we found an
interesting  issue where the receiver stopped generating position fixes for
about 10 seconds, then recovered by itself. This is similar to the issue
posted yesterday by Martin on the NVD8C-CSM unit that reset itself when the
leap-second happened, except our unit did not reset itself, it simply
recovered by itself. We will be working with Ublox to see that this issue
is corrected for future events.

Here are some sample outputs:

LN-Rb w/GPS:
$GPZDA,235958.00,30,06,2015,+00,00*4E
$GPZDA,235959.00,30,06,2015,+00,00*4F
$GPZDA,235960.00,30,06,2015,+00,00*45
$GPZDA,000000.00,01,07,2015,+00,00*4D
$GPZDA,000001.00,01,07,2015,+00,00*4C
$GPZDA,000002.00,01,07,2015,+00,00*4F

LN-Rb w/GLONASS:
$GPZDA,235958.00,30,06,2015,+00,00*4E
$GPRMC,235958.00,A,3611.3765,N,11518.1240,W,0.0,0.0,300615,,*29
$GPZDA,235959.00,30,06,2015,+00,00*4F
$GPRMC,235959.00,A,3611.3765,N,11518.1240,W,0.0,0.0,300615,,*28
$GPZDA,000000.00,01,07,2015,+00,00*4D
$GPRMC,000000.00,A,3611.3765,N,11518.1240,W,0.0,0.0,010715,,*2A
$GPZDA,000001.00,01,07,2015,+00,00*4C
$GPRMC,000001.00,V,0000.0000,N,00000.0000,E,0.0,0.0,010715,,*27  Notice
the unit starts indicating invalid fix and no PVT data here
$GPZDA,000002.00,01,07,2015,+00,00*4F
$GPRMC,000002.00,V,0000.0000,N,00000.0000,E,0.0,0.0,010715,,*24
$GPZDA,000003.00,01,07,2015,+00,00*4E
$GPRMC,000003.00,V,0000.0000,N,00000.0000,E,0.0,0.0,010715,,*25
$GPZDA,000004.00,01,07,2015,+00,00*49
$GPRMC,000004.00,V,0000.0000,N,00000.0000,E,0.0,0.0,010715,,*22
$GPZDA,000005.00,01,07,2015,+00,00*48
$GPRMC,000005.00,V,0000.0000,N,00000.0000,E,0.0,0.0,010715,,*23
$GPZDA,000006.00,01,07,2015,+00,00*4B
$GPRMC,000006.00,V,0000.0000,N,00000.0000,E,0.0,0.0,010715,,*20
$GPZDA,000007.00,01,07,2015,+00,00*4A
$GPRMC,000007.00,V,0000.0000,N,00000.0000,E,0.0,0.0,010715,,*21
$GPZDA,000008.00,01,07,2015,+00,00*45
$GPRMC,000008.00,V,0000.0000,N,00000.0000,E,0.0,0.0,010715,,*2E
$GPZDA,000009.00,01,07,2015,+00,00*44
$GPRMC,000009.00,V,0000.0000,N,00000.0000,E,0.0,0.0,010715,,*2F
$GPZDA,000010.00,01,07,2015,+00,00*4C
$GPRMC,000010.00,V,0000.0000,N,00000.0000,E,0.0,0.0,010715,,*27
$GPZDA,000011.00,01,07,2015,+00,00*4D
$GPRMC,000011.00,A,3611.3784,N,11518.1240,W,0.0,0.0,010715,,*25  Recovers
here
$GPZDA,000011.00,01,07,2015,+00,00*4E
$GPRMC,000011.00,A,3611.3784,N,11518.1240,W,0.0,0.0,010715,,*26
$GPZDA,000012.00,01,07,2015,+00,00*4F
$GPRMC,000012.00,A,3611.3784,N,11518.1240,W,0.0,0.0,010715,,*27
$GPZDA,000013.00,01,07,2015,+00,00*48
$GPRMC,000013.00,A,3611.3784,N,11518.1240,W,0.0,0.0,010715,,*20


Keith



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