Don did not mention which basic receiver is inside his AUTEC box. Some receivers do exhibit glitches. Some of these are documented in my 2000 ION paper Low-cost, High Accuracy GPS Timing available on [1]http://gpstime.com. You might find some of the Timing for VLBI tutorials to be of some interest also. The ONCORE v.3 firmware is known to have glitches 50 nsec glitches every 19.5 nsec. Also, S/A has been turned off since May, 2000 and the US Gov't has made a commitment that it will stay off. The GPS "Y2K" problem occurred in August 1999. The timing broadcast is in terms of elapsed seconds since Jan.6 1980. The seconds are sent as a 20-bit word in order to accommodate 604800 seconds per week, and a 10-bit (range=0-1023) week counter from 1980. The 10-bit counter overflowed 1023 weeks after 1980 in Aug, 2000. Some manufacturers started their conversion algorithm later (like when their first receiver was delivered), and their week ambiguity occurred later. And there may be some manufacturers that have receivers that will glitch at a later day -- who knows? In general these glitches happen at the start of a new GPS week late Saturday nite. Regards, Tom
References 1. http://gpstime.com/ _______________________________________________ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts