NetNews Usenet Archive 1992 #20/NN_1992_20.iso/spool/comp/protocol/time/ntp/871

Text File | 1992-09-09 | 1.5 KB | 37 lines

Newsgroups: comp.protocols.time.ntp
Path: sparky!uunet!decwrl!access.usask.ca!herald.usask.ca!glenn
From: [e-mail] (Glenn Hollinger)
Subject: Motorola GPS Receiver
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Nntp-Posting-Host: herald.usask.ca
Organization: University of Saskatchewan
Date: Wed, 9 Sep 1992 18:00:46 GMT
Lines: 24

The new Motorola GPS Receiver has been mentioned a couple of times here.
I just got a copy of the technical reference manual for this box and
will offer a few notes about it.

1) The unit is a nice piece of work.  A 4 inch diameter 1 inch thick
antenna disk and a 4x3x1 inch system box powered by 12 or 5 volts.

2) The ascii timestamps have a variable delay from 0 to 50 milliseconds.
This is not very good, but see point 3.

3) There is a 1PPS output available.  The accuracy is described as "The 1
PPS (when optionally installed) has a 1 sigma accuracy of +/- 75 nano-
seconds plus a resolution of +/- 52 nanoseconds."  I don't know exactly
what this means.  (Perhaps an expert can comment?)  It appears to be
significantly better than the ascii timestamps and should produce a
decent clock when coupled with a gadget box to the Xntp3 PPS code.

4) The box will speak Motorola binary code (complex), NMEA code, and
do LORAN emulation.

Sounds great!

Glenn Hollinger,                     [e-mail]
University of Saskatchewan.          [phone]