Meinberg LANTIME, Operating Instructions Manual

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GPS167 Features
The hardware of GPS167 is a 100 mm x 160 mm microprocessor board. The front
panel integrates a 2 x 40 character LC display, two LED indicators and 5 push
buttons. The receiver is connected to the antenna/converter unit by a 50
Ω
coaxial
cable (refer to "Mounting the Antenna"). Feeding the antenna/converter occurs DC
insulated via the antenna cable. Optionally an antenna splitter for up to four receivers
connected to one antenna is available.
The navigation message coming in from the satellites is decoded by GPS167´s
microprocessor in order to track the GPS system time with an accuracy of better than
500 ns or 250 nsec (OCXO). Compensation of the RF signal’s propagation delay is
done by automatic determination of the receiver’s position on the globe. A correction
value computed from the satellites´ navigation messages increases the accuracy of the
board’s TCXO or OCXO to 10
-9 and automatically compensates the oscillators aging.
The last recent value is restored from the battery buffered memory at power-up.
Time Zone and Daylight Saving
GPS system time differs from the universal time scale (UTC) by the number of leap
seconds which have been inserted into the UTC time scale after GPS had been
initiated in 1980. The current number of leap seconds is part of the navigation
message supplied by the satellites, so GPS167´s internal real time is based on UTC.
Conversion to local time including handling of daylight saving year by year can be
done by the receiver’s microprocessor if the corresponding parameters are set up by
the GPS Monitor (included Windows software).
Internally LANTIME always runs on UTC based time. NTP calculates this UTC time
from the GPS receivers local time. The time zone of LANTIME is fixed to UTC.
However, the time monitored on the LC display is the GPS receiver's local time.
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