SeaSpace TeraScan 1.5M, Operation And Maintenance Manual

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186
SeaSpace Corporation
10.3.5 date
Check and/or update the system time.
Description:
For accurate satellite tracking, system time must be correct.
Check System Time:
To check system time, use the date command as follows to compare the time on your system against a
clock with high-accuracy GMT time, such as that available on the web at
http://wwp.greenwichmeantime.com:
1. Use your web browser to go to: http://www.greenwichmeantime.com.
2. At the command prompt, type in the date command, then watch
the time on the web page
and note the exact time (the seconds field) at which you press the Enter key for the
date
command.
3. Compare the two times. They should match down to the second. If the times differ, this
indicates a problem with either the GPS or the NTP software that polls the GPS for
time.
Setting System Time:
In the event that the NTP service is lost, or the GPS is down, the superuser can use the date command
as follows to reset the system time until the GPS is available again.
1. If the time is off by less than a few minutes, run the
date
command, using the
-a
option to
adjust the system clock by a specified number of seconds. For example:
# date -a 5
( increments the system clock by 5 seconds )
# date -a -135
( decrements the system clock by 135 seconds )
2. Recheck the clock:
# date
3. If necessary, continue adjusting the time in increments until the system time is correct.
4. If the time is off by more than a few minutes, run the
date
command with the
-s
option to reset
the clock to a specific time. For example:
# date -s 12:34:56
( sets system time to 12:34:56 GMT )
5. If the date is also incorrect, run the
date
command with the
-u
option to reset the clock to a
specific date and time. For date and time format use: MMDDhhmm.ss. For example:
# date -u 03311234.56
( sets system time to 12:34:56 GMT on March 31 )
Do NOT change the time while a pass is being tracked.