sbas moved - online edit of handbook/survey/gps.htm

handbook/survey/gps.htm

@@ -66,9 +66,6 @@ of the entrance. </p>
     <p>Also <em>sketch</em> the entrance in comparison to other holes close by - in the notebook, which you have with you, and always bring 2 pencils.
 
   
-<h4>SBAS</h4>
-Check whether your phone is using SBAS "Satellite-based Augmentation Services", which is another name for EGNOS, the differential GPS system.
-You need to record if SBAS is in operation whenever you record the position of a cave entrance (and ideally whenever you take a photo too, but that would be unrealistic). A screenshot of the GPStest screen does this for you.
 
   
 <p>Differential GPS (SBAS) has existed since 2018, but it is often not actually available on a phone. The number of satellites now renders previous advice obsolete (e.g. Wookey's 1996 article).
@@ -129,6 +126,10 @@ on coordinate systems</a> has been moved to a different page. If you are really
   
 <p>Unfortunately RTPPP  has not actually caught on [2026] and it is still only available for experts and phones  supporting L2 and L5 frequencies have been slower to appear than we hoped. Read Wikipedia on <a href="https://en.wikipedia.org/wiki/Real-time_kinematic_positioning">Real-time kinematic positioning (RTK)</a>.
 
+<h4>SBAS</h4>
+We used to be very concerned whether we were using SBAS "Satellite-based Augmentation Services" or not. (This is another name for EGNOS, the differential GPS system.) A screenshot of the GPStest screen does this for you so you don't need to worry about this.
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 <a href="newcave.html">Next survey guide page</a> - 'Base Camp: getting it in to the computer'<br />
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