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diff --git a/contrib/ntp/html/driver11.htm b/contrib/ntp/html/driver11.htm new file mode 100644 index 0000000..6e5dd7a --- /dev/null +++ b/contrib/ntp/html/driver11.htm @@ -0,0 +1,150 @@ +<HTML> +<HEAD> + <META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=iso-8859-1"> + <META NAME="GENERATOR" CONTENT="Mozilla/4.01 [en] (Win95; I) [Netscape]"> + <TITLE>Arbiter 1088A/B GPS Receiver +</TITLE> +</HEAD> +<BODY> + +<H3> +Arbiter 1088A/B GPS Receiver</H3> + +<HR> +<H4> +Synopsis</H4> +Address: 127.127.11.<I>u</I> +<BR>Reference ID: <TT>GPS</TT> +<BR>Driver ID: <TT>GPS_ARBITER</TT> +<BR>Serial Port: <TT>/dev/gps<I>u</I></TT>; 9600 baud, 8-bits, no parity +<BR>Features: <TT>tty_clk</TT> +<H4> +Description</H4> +This driver supports the Arbiter 1088A/B Satellite Controlled Clock. The +claimed accuracy of this clock is 100 ns relative to the PPS output when +receiving four or more satellites. + +<P>The receiver should be configured before starting the NTP daemon, in +order to establish reliable position and operating conditions. It does +not initiate surveying or hold mode. For use with NTP, the daylight savings +time feature should be disables (<TT>D0</TT> command) and the broadcast +mode set to operate in UTC (<TT>BU</TT> command). + +<P>The timecode format supported by this driver is selected by the poll +sequence <TT>B5</TT>, which initiates a line in the following format to +be repeated once per second until turned off by the <TT>B0</TT> command. + +<P>Format <TT>B5</TT> (24 ASCII printing characters): +<PRE><cr><lf>i yy ddd hh:mm:ss.000bbb + +on-time = <cr> +i = synchronization flag (' ' = locked, '?' = unlocked) +yy = year of century +ddd = day of year +hh:mm:ss = hours, minutes, seconds +.000 = fraction of second (not used) +bbb = tailing spaces for fill</PRE> +The alarm condition is indicated by a '?' at i, which indicates the receiver +is not synchronized. In normal operation, a line consisting of the timecode +followed by the time quality character (TQ) followed by the receiver status +string (SR) is written to the clockstats file. + +<P>The time quality character is encoded in IEEE P1344 standard: + +<P>Format <TT>TQ</TT> (IEEE P1344 estimated worst-case time quality) +<PRE>0 clock locked, maximum accuracy +F clock failure, time not reliable +4 clock unlocked, accuracy < 1 us +5 clock unlocked, accuracy < 10 us +6 clock unlocked, accuracy < 100 us +7 clock unlocked, accuracy < 1 ms +8 clock unlocked, accuracy < 10 ms +9 clock unlocked, accuracy < 100 ms +A clock unlocked, accuracy < 1 s +B clock unlocked, accuracy < 10 s</PRE> +The status string is encoded as follows: + +<P>Format <TT>SR</TT> (25 ASCII printing characters) +<PRE>V=vv S=ss T=t P=pdop E=ee + +vv = satellites visible +ss = relative signal strength +t = satellites tracked +pdop = position dilution of precision (meters) +ee = hardware errors</PRE> +A three-stage median filter is used to reduce jitter and provide a dispersion +measure. The driver makes no attempt to correct for the intrinsic jitter +of the radio itself. +<H4> +Monitor Data</H4> +When enabled by the <TT>flag4</TT> fudge flag, an additional line containing +the latitude, longitude, elevation and optional deviation data is written +to the <TT>clockstats</TT> file. The deviation data operates with an external +pulse-per-second (PPS) input, such as a cesium oscillator or another radio +clock. The PPS input should be connected to the B event channel and the +radio initialized for deviation data on that channel. The deviation data +consists of the mean offset and standard deviation of the external PPS +signal relative the GPS signal, both in microseconds over the last 16 seconds. +<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> +Not used by this driver.</DD> + +<DT> +<TT>flag3 0 | 1</TT></DT> + +<DD> +Not used by this driver.</DD> + +<DT> +<TT>flag4 0 | 1</TT></DT> + +<DD> +Enable verbose <TT>clockstats</TT> recording if set.</DD> +</DL> +Additional Information + +<P><A HREF="refclock.htm">Reference Clock Drivers</A> +<HR> +<ADDRESS> +David L. Mills (mills@udel.edu)</ADDRESS> + +</BODY> +</HTML> |
