Hi: I'm not sure if Trimble does it on the Resolution T, but on the Trimpack GPS receivers, http://www.pacificsites.com/~brooke/Trimpack.shtml#BUB have a Lithium battery soldered to one of the PCBs and a Dallas chip that turns all the RAM into non volatile memory (just like core memory in operation). This means that when powered up it not only has the almanac and ephemeris data for all the satellites it also has the fix information so the warm start time is very short. They say if the receiver is moved more than 100 km TTFT will be longer. My Trimpacks which were built in the 1990 (Gulf war) time period all have good batteries, so the current needed to do this must be very small.
The sawtooth correction can be used with hardware to move the 1 PPS edge or it can be used in software where a computer does the math on the measured time interval. Have Fun, Brooke Clarke, N6GCE [EMAIL PROTECTED] wrote: > . . . > >Also, the Motorola parts have one drawback: they need a Lithium battery (or >similar) to keep the most recent Almanac. I have found that the TTFF (first >fix) can take quite long if the battery is weak (<2V) and the RTC stops due >to >this, or if there is no Almanac in Memory. Don't know how the Trimble unit >behaves. > . . . . _______________________________________________ time-nuts mailing list [email protected] https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
