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author | Gary E. Miller <gem@rellim.com> | 2019-05-27 15:03:32 -0700 |
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committer | Gary E. Miller <gem@rellim.com> | 2019-05-27 15:03:32 -0700 |
commit | 6de94e9274c0ccd76927b5043fe159dc269b0aa1 (patch) | |
tree | d7af27aaeb03b5f633de8d6eb91b557d0e3af0f0 /www/gpsd-time-service-howto.adoc | |
parent | 4bc6a54b1f337674777181b80026e992b47ca4cd (diff) | |
parent | 0402eb81691882b4d693f9009f1f7369b205fa1d (diff) | |
download | gpsd-6de94e9274c0ccd76927b5043fe159dc269b0aa1.tar.gz |
Merge branch 'master' of ssh://git.sv.gnu.org/srv/git/gpsd
Diffstat (limited to 'www/gpsd-time-service-howto.adoc')
-rw-r--r-- | www/gpsd-time-service-howto.adoc | 7 |
1 files changed, 4 insertions, 3 deletions
diff --git a/www/gpsd-time-service-howto.adoc b/www/gpsd-time-service-howto.adoc index 3bee4720..c4ae7553 100644 --- a/www/gpsd-time-service-howto.adoc +++ b/www/gpsd-time-service-howto.adoc @@ -137,12 +137,13 @@ second and the following subframe broadcast. GPS date and time are subject to a rollover problem in the 10-bit week number counter, which will re-zero every 1024 weeks (roughly every 19.6 -years). The last rollover (and the first since GPS went live in 1980) -was in Aug-1999; the next will fall in Apr-2019. The new "CNAV" data +years). The first rollover since GPS went live in 1980 was in Aug-1999, +followed by Apr-2019, the next will be in Nov-2038 (the 32-bit and POSIX +issues will probably be more important by then). The new "CNAV" data format extends the week number to 13 bits, with the first rollover occurring in Jan-2137, but this is only used with some newly added GPS signals, and is unlikely to be usable in most consumer-grade receivers -prior to the 2019 rollover. +currently. For accurate time reporting, therefore, a GPS requires a supplemental time references sufficient to identify the current rollover period, |