[time-nuts] GPS receivers and the Leap Second

Miguel Barbosa Gonçalves m at mbg.pt
Sun Jan 1 09:16:43 EST 2017


Hi!

In my network I have 2 Meinberg M200 clocks and 4 other GPS receivers (1
Sure GPS Evaluation board, 2 Garmin 18 LVC and a uBlox EVK-6N). I
recorded the GPS timecode strings across 00:00 UTC to see how they would
react to the leap second:

Sure GPS
timecode="$GPGGA,235955.000,4055.2138,N,00829.6016,W,2,7,1.11,267.3,M,51.2,M,0000,0000*4E",
timecode="$GPGGA,235956.000,4055.2138,N,00829.6016,W,2,7,1.11,267.3,M,51.2,M,0000,0000*4D",
timecode="$GPGGA,235957.000,4055.2138,N,00829.6015,W,2,7,1.11,267.3,M,51.2,M,0000,0000*4F",
timecode="$GPGGA,235958.000,4055.2138,N,00829.6015,W,2,7,1.11,267.3,M,51.2,M,0000,0000*40",
timecode="$GPGGA,235959.000,4055.2138,N,00829.6015,W,2,7,1.11,267.3,M,51.2,M,0000,0000*41",
timecode="$GPGGA,235959.000,4055.2138,N,00829.6015,W,2,7,1.11,267.3,M,51.2,M,0000,0000*41",
timecode="$GPGGA,000000.000,4055.2138,N,00829.6015,W,2,7,1.11,267.3,M,51.2,M,0000,0000*40",
timecode="$GPGGA,000001.000,4055.2138,N,00829.6015,W,2,7,1.11,267.3,M,51.2,M,0000,0000*41",
timecode="$GPGGA,000002.000,4055.2138,N,00829.6015,W,2,7,1.11,267.3,M,51.2,M,0000,0000*42",
timecode="$GPGGA,000003.000,4055.2138,N,00829.6015,W,2,6,1.15,267.3,M,51.2,M,0000,0000*46",
timecode="$GPGGA,000004.000,4055.2138,N,00829.6015,W,2,6,1.15,267.3,M,51.2,M,0000,0000*41",
timecode="$GPGGA,000005.000,4055.2138,N,00829.6015,W,2,7,1.07,267.3,M,51.2,M,0000,0000*42",

Meinberg #1
timecode="\x0231.12.16; 6; 23:59:55; +00:00;     A  ; 40.9204N   8.4936W
 343m\x03",
timecode="\x0231.12.16; 6; 23:59:56; +00:00;     A  ; 40.9204N   8.4936W
 343m\x03",
timecode="\x0231.12.16; 6; 23:59:57; +00:00;     A  ; 40.9204N   8.4936W
 343m\x03",
timecode="\x0231.12.16; 6; 23:59:58; +00:00;     A  ; 40.9204N   8.4936W
 343m\x03",
timecode="\x0231.12.16; 6; 23:59:59; +00:00;     A  ; 40.9204N   8.4936W
 343m\x03",
timecode="\x0231.12.16; 6; 23:59:60; +00:00;       L; 40.9204N   8.4936W
 343m\x03",
timecode="\x0201.01.17; 7; 00:00:00; +00:00;        ; 40.9204N   8.4936W
 343m\x03",
timecode="\x0201.01.17; 7; 00:00:01; +00:00;        ; 40.9204N   8.4936W
 343m\x03",
timecode="\x0201.01.17; 7; 00:00:02; +00:00;        ; 40.9204N   8.4936W
 343m\x03",
timecode="\x0201.01.17; 7; 00:00:03; +00:00;        ; 40.9204N   8.4936W
 343m\x03",
timecode="\x0201.01.17; 7; 00:00:04; +00:00;        ; 40.9204N   8.4936W
 343m\x03",
timecode="\x0201.01.17; 7; 00:00:05; +00:00;        ; 40.9204N   8.4936W
 343m\x03",

Meinberg #2
timecode="\x0231.12.16; 6; 23:59:55; +00:00;     A  ; 40.9205N   8.4936W
 337m\x03",
timecode="\x0231.12.16; 6; 23:59:56; +00:00;     A  ; 40.9205N   8.4936W
 337m\x03",
timecode="\x0231.12.16; 6; 23:59:57; +00:00;     A  ; 40.9205N   8.4936W
 337m\x03",
timecode="\x0231.12.16; 6; 23:59:58; +00:00;     A  ; 40.9205N   8.4936W
 337m\x03",
timecode="\x0231.12.16; 6; 23:59:59; +00:00;     A  ; 40.9205N   8.4936W
 337m\x03",
timecode="\x0231.12.16; 6; 23:59:60; +00:00;       L; 40.9205N   8.4936W
 337m\x03",
timecode="\x0201.01.17; 7; 00:00:00; +00:00;        ; 40.9205N   8.4936W
 337m\x03",
timecode="\x0201.01.17; 7; 00:00:01; +00:00;        ; 40.9205N   8.4936W
 337m\x03",
timecode="\x0201.01.17; 7; 00:00:02; +00:00;        ; 40.9205N   8.4936W
 337m\x03",
timecode="\x0201.01.17; 7; 00:00:03; +00:00;        ; 40.9205N   8.4936W
 337m\x03",
timecode="\x0201.01.17; 7; 00:00:04; +00:00;        ; 40.9205N   8.4936W
 337m\x03",
timecode="\x0201.01.17; 7; 00:00:05; +00:00;        ; 40.9205N   8.4936W
 337m\x03",

uBlox EVK-6N
timecode="$GPGGA,235955.00,4055.21472,N,00829.59411,W,1,07,1.11,251.5,M,49.9,M,,*4F",
timecode="$GPGGA,235956.00,4055.21472,N,00829.59416,W,1,07,1.11,251.7,M,49.9,M,,*49",
timecode="$GPGGA,235957.00,4055.21472,N,00829.59420,W,1,07,1.11,251.8,M,49.9,M,,*42",
timecode="$GPGGA,235958.00,4055.21474,N,00829.59424,W,1,08,1.11,252.1,M,49.9,M,,*4A",
timecode="$GPGGA,235959.00,4055.21475,N,00829.59429,W,1,08,1.11,252.3,M,49.9,M,,*45",
timecode="$GPGGA,235960.00,4055.21477,N,00829.59433,W,1,08,1.11,252.6,M,49.9,M,,*43",
timecode="$GPGGA,235960.00,4055.21477,N,00829.59433,W,1,08,1.11,252.6,M,49.9,M,,*43",
timecode="$GPGGA,000001.00,4055.21479,N,00829.59440,W,1,08,1.11,253.0,M,49.9,M,,*44",
timecode="$GPGGA,000002.00,4055.21481,N,00829.59443,W,1,08,1.11,253.3,M,49.9,M,,*40",
timecode="$GPGGA,000003.00,4055.21482,N,00829.59447,W,1,08,1.11,253.6,M,49.9,M,,*43",
timecode="$GPGGA,000004.00,4055.21484,N,00829.59451,W,1,08,1.11,253.8,M,49.9,M,,*4B",
timecode="$GPGGA,000005.00,4055.21485,N,00829.59454,W,1,08,1.11,254.1,M,49.9,M,,*40",

Garmin 18 LVC #1
timecode="$GPGGA,235955,4055.2362,N,00829.5576,W,2,07,1.2,248.8,M,51.7,M,,*5C",
timecode="$GPGGA,235956,4055.2362,N,00829.5576,W,2,07,1.2,248.8,M,51.7,M,,*5F",
timecode="$GPGGA,235957,4055.2362,N,00829.5576,W,2,07,1.2,248.5,M,51.7,M,,*53",
timecode="$GPGGA,235958,4055.2362,N,00829.5576,W,2,07,1.2,248.5,M,51.7,M,,*5C",
timecode="$GPGGA,235959,4055.2362,N,00829.5576,W,2,07,1.2,248.5,M,51.7,M,,*5D",
timecode="$GPGGA,235959,4055.2362,N,00829.5576,W,2,07,1.2,248.5,M,51.7,M,,*5D",
timecode="$GPGGA,000000,4055.2361,N,00829.5576,W,2,07,1.2,248.4,M,51.7,M,,*5E",
timecode="$GPGGA,000001,4055.2361,N,00829.5575,W,2,07,1.2,248.2,M,51.7,M,,*5A",
timecode="$GPGGA,000002,4055.2361,N,00829.5575,W,2,07,1.2,248.0,M,51.7,M,,*5B",
timecode="$GPGGA,000003,4055.2361,N,00829.5575,W,2,07,1.2,247.9,M,51.7,M,,*5C",
timecode="$GPGGA,000004,4055.2360,N,00829.5575,W,2,07,1.2,247.9,M,51.7,M,,*5A",
timecode="$GPGGA,000005,4055.2360,N,00829.5575,W,2,07,1.2,247.8,M,51.7,M,,*5A",


Garmin 18 LVC #2
timecode="$GPGGA,235955,4055.2222,N,00829.6108,W,1,07,1.4,256.3,M,51.7,M,,*56",
timecode="$GPGGA,235956,4055.2222,N,00829.6108,W,1,07,1.4,255.8,M,51.7,M,,*5D",
timecode="$GPGGA,235957,4055.2222,N,00829.6108,W,1,07,1.4,255.2,M,51.7,M,,*56",
timecode="$GPGGA,235958,4055.2222,N,00829.6108,W,1,06,1.4,254.5,M,51.7,M,,*5E",
timecode="$GPGGA,235959,4055.2222,N,00829.6108,W,1,06,1.4,253.8,M,51.7,M,,*55",
timecode="$GPGGA,235959,4055.2222,N,00829.6108,W,1,06,1.4,253.8,M,51.7,M,,*55",
timecode="$GPGGA,000000,4055.2222,N,00829.6108,W,1,06,1.4,252.5,M,51.7,M,,*58",
timecode="$GPGGA,000001,4055.2222,N,00829.6108,W,1,06,1.4,251.8,M,51.7,M,,*57",
timecode="$GPGGA,000002,4055.2222,N,00829.6108,W,1,06,1.4,251.2,M,51.7,M,,*5E",
timecode="$GPGGA,000003,4055.2222,N,00829.6108,W,1,06,1.4,250.5,M,51.7,M,,*59",
timecode="$GPGGA,000004,4055.2222,N,00829.6108,W,1,06,1.4,249.9,M,51.7,M,,*5A",
timecode="$GPGGA,000005,4055.2222,N,00829.6108,W,1,06,1.4,249.3,M,51.7,M,,*51",


Apparently only the Meinbergs do it properly. The uBlox repeats the 60
second mark twice. Quite odd.

I found two servers that weren't ready for the leap second

$ date; ntpq -p 192.168.0.129
Sun Jan  1 00:08:46 WET 2017
     remote           refid      st t when poll reach   delay   offset 
     jitter
==============================================================================
+192.168.0.5     .GPS.            1 u   19   64  377    1.418    0.005  
0.044
*192.168.0.98    .GPS.            1 u   11   64  377    1.369   -0.017  
0.062
-192.168.0.99    .GPS.            1 u   66   64  377    1.381    0.006 
15.381
-192.168.0.100   .GPS.            1 u   32   64  377    1.411    0.060  
0.037
+192.168.0.101   .GPS.            1 u   28   64  377    1.414    0.001  
0.020
+192.168.0.102   .GPS.            1 u   58   64  377    1.312   -0.020  
0.060
-62.XX.YYY.65    172.20.9.1       2 u   47   64  377    8.586  1000.61  
0.394
 62.XX.YYY.66    172.20.9.1       2 u   66   64  377    8.756  1000.84  
 0.097
$ date; ntpq -p 192.168.0.129
Sun Jan  1 00:09:18 WET 2017
     remote           refid      st t when poll reach   delay   offset 
     jitter
==============================================================================
+192.168.0.5     .GPS.            1 u   51   64  377    1.418    0.005  
0.044
*192.168.0.98    .GPS.            1 u   43   64  377    1.369   -0.017  
0.062
-192.168.0.99    .GPS.            1 u   31   64  377    1.380   -0.018  
0.056
-192.168.0.100   .GPS.            1 u   64   64  377    1.411    0.060  
0.037
+192.168.0.101   .GPS.            1 u   60   64  377    1.414    0.001  
0.020
+192.168.0.102   .GPS.            1 u   26   64  377    1.312   -0.020  
0.066
-62.XX.YYY.65    172.20.9.1       2 u   13   64  377    8.586  1000.61  
0.361
 62.XX.YYY.66    172.20.9.1       2 u   31   64  377    8.756  1000.84  
 0.098
$ date; ntpq -p 192.168.0.129
Sun Jan  1 00:12:30 WET 2017
     remote           refid      st t when poll reach   delay   offset 
     jitter
==============================================================================
-192.168.0.5     .GPS.            1 u   45   64  377    1.563    0.064  
0.026
-192.168.0.98    .GPS.            1 u   38   64  377    1.478    0.072  
0.051
+192.168.0.99    .GPS.            1 u   23   64  377    1.380   -0.018  
0.057
*192.168.0.100   .GPS.            1 u   61   64  377    1.379   -0.016  
0.065
+192.168.0.101   .GPS.            1 u   55   64  377    1.414    0.001  
0.031
-192.168.0.102   .GPS.            1 u   22   64  377    1.425    0.070  
0.029
-62.XX.YYY.65    172.20.9.1       2 u   13   64  377    8.658  1000.66  
0.362
-62.XX.YYY.66    172.20.9.1       2 u   25   64  377    8.756  1000.84  
0.115

But that was to be expected

$ ntpq -c rv 62.XX.YYY.65
associd=0 status=0600 leap_none, sync_ntp, no events, unspecified,
system="cisco", leap=00, stratum=2, rootdelay=2.380,
rootdispersion=0.030, peer=57094, refid=172.20.9.1,
reftime=dc138abf.45927e50  Sun, Jan  1 2017 14:03:43.271, poll=10,
clock=dc138cb1.5c6d58da  Sun, Jan  1 2017 14:12:01.361, phase=0.024,
freq=175.72, error=0.02

Cheers,
Miguel


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