Specifications

APPENDIX C. RESULTS OBTAINED DURING DEVELOPMENT 38
Figure C.1: GPS Positional parameters for a period of 5 days
the difference between the values samples at two consecutive 1Hz PPS pulses and we saw
that the values varied between 39999995 and 40000005. These was explained by the fact
that the GPS adjusts its output signals to match the satellites.
Figure C.2: Ticks per second
C.3 Global synchronization test
For this test we installed 2 GPS cards in two computers located in different buildings.
The distance between the buildings was of several hundred me ters and the antennas were
mounted on the roofs of the buildings.
There are two different methods for global synchronization - one that uses a periodic up-
date/correction of the clocks and one that does not. Both methods use the same procedure
for the initial reset.
The method without the periodic update is not accurate enough for our purpos es (the