Index: trunk/BNC/src/bnchelp.html
===================================================================
--- trunk/BNC/src/bnchelp.html	(revision 10693)
+++ trunk/BNC/src/bnchelp.html	(revision 10694)
@@ -4604,7 +4604,20 @@
 satellite Antenna Phase Centers (APC). It is so far only the satellite clock corrections, which are combined by BNC
 while orbit corrections in the combination product are just taken over from one of the incoming
-Broadcast Correction streams. Combining only clock corrections using a fixed orbit reference imposes the potential
-to introduce some analysis inconsistencies. We will therefore consider improvements on this approach.
-</p>
+Broadcast Correction streams. Combining only clock corrections using a fixed orbit reference (which means the individual orbit of
+an incoming AC = Master orbit) imposes the potential to introduce analysis inconsistencies. Hence, some a priori corrections dC
+are applied before clock combination, to compensate for the inconsistency between MasterAC and other orbits.
+This should include corrections for inconsistent frames, attitude mode and phase center offset:
+</p>
+<pre>
+ dC = dC_frame + dC_att + dC_pco [m]
+</pre>
+ But because at present, no PCO information is available via SSR, we consider only
+<pre>
+ dC_frame = Orb_AC * (Orb_AC - Orb_MasterAC) / Range_sat
+</pre>
+<pre>
+ dC_att = (yawAngle_AC - yawAngle_MasterAC) / (2*PI) * wavelength(IF)
+</pre>
+
 <p>
 The 'Combine Corrections' functionality may be of interrest because: