diff options
| author | roberto <roberto@FreeBSD.org> | 1999-12-09 13:01:21 +0000 |
|---|---|---|
| committer | roberto <roberto@FreeBSD.org> | 1999-12-09 13:01:21 +0000 |
| commit | ef64b99e8412f2273dd2e8b3291c2f78ffc4667f (patch) | |
| tree | fc0cfa1aab0ff6b228f511b410733ef4f35d1ead /contrib/ntp/html/driver30.htm | |
| download | FreeBSD-src-ef64b99e8412f2273dd2e8b3291c2f78ffc4667f.zip FreeBSD-src-ef64b99e8412f2273dd2e8b3291c2f78ffc4667f.tar.gz | |
Virgin import of ntpd 4.0.98f
Diffstat (limited to 'contrib/ntp/html/driver30.htm')
| -rw-r--r-- | contrib/ntp/html/driver30.htm | 153 |
1 files changed, 153 insertions, 0 deletions
diff --git a/contrib/ntp/html/driver30.htm b/contrib/ntp/html/driver30.htm new file mode 100644 index 0000000..8d547b1 --- /dev/null +++ b/contrib/ntp/html/driver30.htm @@ -0,0 +1,153 @@ +<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"> +<HTML> +<HEAD> + <META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=iso-8859- +1"> + <META NAME="GENERATOR" CONTENT="Mozilla/4.06 [en] (X11; I; FreeBSD +3.0-CURRENT i386) [Netscape]"> + <TITLE>Motorola Oncore GPS Receiver +</TITLE> +</HEAD> +<BODY> + +<H3> +Motorola Oncore GPS receiver</H3> + +<HR> +<H4> +Synopsis</H4> + +Address: 127.127.30.0 +<BR>Reference ID: <TT>GPS</TT> +<BR>Driver ID: ONCORE +<BR>Serial Port: <TT>/dev/cuaa0</TT>; 9600 baud, 8-bits, no parity +<BR>PPS Port: <TT>/dev/xpps0</TT>; <TT>PPS_CAPTUREASSERT</TT> +required, <TT>PPS_OFFSETASSERT</TT> supported. +<H4> +Description</H4> +This driver supports various models of the <A +HREF="http://www.mot.com/AECS/PNSB/products">Motorola Oncore GPS +receivers</A>. as long as they support the <I>Motorola Binary +Protocol</I>. + +<P>The two most interesting version of the Oncore are the "UT+" +and the "Remote" which is a prepackaged "UT+". The evaluation kit +can also be recommended, it interfaces to a PC straightaway, using the +parallel port for PPS input (supported under FreeBSD), and packs the +receiver in a nice and sturdy box. +<BR> +<CENTER><TABLE NOSAVE > +<TR NOSAVE> +<TD NOSAVE><IMG SRC="pic/oncore_utplusbig.gif" HEIGHT=124 +WIDTH=210></TD> + +<TD><IMG SRC="pic/oncore_evalbig.gif" HEIGHT=124 WIDTH=182></TD> + +<TD><IMG SRC="pic/oncore_remoteant.jpg" HEIGHT=188 WIDTH=178></TD> +</TR> + +<TR> +<TD> +<CENTER>UT+ oncore</CENTER> +</TD> + +<TD> +<CENTER>Evaluation kit</CENTER> +</TD> + +<TD> +<CENTER>Oncore Remote</CENTER> +</TD> +</TR> +</TABLE></CENTER> + +<P>The driver requires a standard <TT>PPS</TT> interface for the pulse- +per-second output from the receiver. The serial data stream alone +does not provide precision time stamps (0-50msec variance, according to +the manual), whereas the PPS output is precise down to 50 nsec (1 sigma) +for the UT models. <P>The driver will use the "position hold" mode if +available, with either the receivers built-in site-survey or a similar +algorithm implemented in this driver. +<H4> +Monitor Data</H4> +The driver is quite chatty on stdout if ntpd is run with +debugging. +A manual will be required though. +<H4> +Fudge Factors</H4> + +<DL> +<DT> +<TT>time1 <I>time</I></TT></DT> + +<DD> +Specifies the time offset calibration factor, in seconds and fraction, +with default 0.0.</DD> + +<DT> +<TT>time2 <I>time</I></TT></DT> + +<DD> +Not used by this driver.</DD> + +<DT> +<TT>stratum <I>number</I></TT></DT> + +<DD> +Specifies the driver stratum, in decimal from 0 to 15, with default +0.</DD> + +<DT> +<TT>refid <I>string</I></TT></DT> + +<DD> +Specifies the driver reference identifier, an ASCII string from one to +four characters, with default <TT>GPS</TT>.</DD> + +<DT> +<TT>flag1 0 | 1</TT></DT> + +<DD> +Not used by this driver.</DD> + +<DT> +<TT>flag2 0 | 1</TT></DT> + +<DD> +Assume GPS receiver is on a mobile platform if set.</DD> + +<DT> +<TT>flag3 0 | 1</TT></DT> + +<DD> +Not used by this driver.</DD> + +<DT> +<TT>flag4 0 | 1</TT></DT> + +<DD> +Not used by this driver.</DD> +</DL> +<B>Additional Information</B><B></B> +<P>The driver has been developed under FreeBSD, and may still be pretty +FreeBSD centric. Patches are most welcome. +<P><B>Performance</B><B></B> +<P>Really good. With the UT+, the generated PPS pulse is +referenced +to UTC(GPS) with better than 50 nsec (1 sigma) accuracy. The +limiting factor will be the timebase of the computer and the precision +with which you can timestamp the rising flank of the +PPS signal. +Using FreeBSD, a FPGA based Timecounter/PPS interface +and +an ovenized quartz oscillator, that performance has been reproduced. + For +more details on this aspect: <A +HREF="http://phk.freebsd.dk/rover.html">Sub-Microsecond +timekeeping under FreeBSD</A> +<HR> +<ADDRESS> +Poul-Henning Kamp (phk@FreeBSD.org)</ADDRESS> + +</BODY> +</HTML> |
