Document realtime tracking.

diff --git a/xmldoc/chapters/use.xml b/xmldoc/chapters/use.xml
index a11967bf2c6c26e3556a4f54288d1eff8843ae2f..6d8115094c55a966fb3f592079aa89b6b509d588 100644 (file)
--- a/xmldoc/chapters/use.xml
+++ b/xmldoc/chapters/use.xml
@@ -216,5 +216,23 @@ merged data to multiple destinations.
        The inifile mechanism can be disabled with an empty filename.
     </para>
     <screen format="linespecific">gpsbabel -p "" -i gpx -f something.gpx -o tiger -F -</screen>
+</sect1>
+<sect1 id="tracking">
+  <title>Realtime tracking</title>
+    <para>
+      Introduced in GPSBabel 1.3.1, we now have an <emphasis>experimental</emphasis>  feature for realtime tracking via the new '-T' option.  This reads position reports from selected formats and writes an output file when a position report is received. 
+    </para>
+    <para>
+         As of this writing, Garmin's PVT protocol and NMEA are supported 
+         inputs and KML is supported on output.   Additional formats 
+         may be added by interested parties later.
+    </para>
+    <para>
+    <screen format="linespecific">gpsbabel -T -i garmin -f usb: -o kml -F xxx.kml</screen>
+         Will read the USB-connected Garmin and rewrite 'xxx.kml' atomically,
+         suitable for a self-refreshing network link in Google Earth.
+    </para>
+   
+  
 </sect1>
 </chapter>