The HP 1000's internal clock is synchronised to the maser frequency standard via a 1 MHz signal which feeds directly into the HP 1000. Days, hours, minutes and seconds are setup manually and then synchronised to the 1PPS via the pulsar timer.
PC-STEER resynchronises the internal software clock once a second to be synchronous with the 1PPS signal. Days, hours, minutes and seconds are setup manually and then synchronised to the 1PPS.
Time must be kept to sufficient precision to ensure that position calculation is accurate to at least 1/10 of a beamwidth at the highest observed frequency (22 GHz) i.e. 12 arcseconds. PC-STEER presently does all its calculations to 1 arcsecond accuracy and this should be maintained. Entry of leap seconds must also be taken account of. For pointing the telescope time must be kept accurate to within 1/10 of a STEER cycle (10ms) for the hardware and 1/2 STEER cycle (50ms) for software.
Ideally all computers on the network should have the same time. This helps for sharing of files via NFS and correlating events recorded by different computers. A freely available network protocol exists for Unix called Network Time Protocol (ntp) which is capable of synchronising computers over Ethernet to within millisecond precision. All computers should be time synchronised via ntp.