Changeset 11079 in ntrip for trunk/BNC/src/bnchelp.html

Timestamp:

Oct 8, 2026, 11:47:35 AM (2 days ago)

Author:

stuerze

Message:

combi can be based on CoM

File:

• trunk/BNC/src/bnchelp.html (modified) (2 diffs)

trunk/BNC/src/bnchelp.html

@@ -6323 +6323 @@
   </p>
   <p>
+    Whether the orbit corrections refer to the satellite's Antenna Phase Center (APC) or to its Center of Mass (CoM) is
+    derived from the name of the correction stream or file: names beginning with 'SSRA' refer to the APC, the combined
+    corrections 'INTERNAL' always refer to the APC as well; all others are taken as CoM. For APC corrections, only the
+    differences of the satellite antenna offsets to that of the reference frequency are applied.
+  </p>
+  <p>
     Default value for 'ANTEX file' is an empty option field, meaning that you do not want to correct observations for
     Antenna Phase Center offsets and variations.
@@ -8096 +8102 @@
     - despite the fact, that the delivered code biases of an AC may contain contributions from other biases, also phase
     biases.
+  </p>
+  <p>
+    <b>APC and CoM streams:</b> The orbits of Broadcast Correction streams refer either to the satellite's Antenna Phase
+    Center (APC, stream names 'SSRA...', reference frequency of the IGS-SSR and RTCM-SSR conventions) or to its Center
+    of Mass (CoM, 'SSRC...'). If streams of both kinds are combined and an ANTEX file is specified ('Upload
+    Corrections' panel), the combination is done in the CoM frame: the orbits of the APC streams are converted to CoM
+    with the satellite antenna offsets of the ANTEX file and the attitude model selected for the AC ('Computed', 'SSR'
+    or 'Nominal'). The result is converted to the APC for upload streams referring to the APC and for the combined
+    corrections passed on to BNC's PPP ('INTERNAL'), which always refer to the APC. As most ACs provide
+    both kinds of streams, combining CoM streams is recommended: the combined SP3 and CoM results then do not depend on
+    BNC's attitude model and ANTEX file, only the uploaded APC streams do. Without an ANTEX file, or if all streams
+    are of one kind, the combination is done in the frame of the master AC; streams of the other kind are not
+    combined, which is reported in the logfile at most once per hour per AC and system.
   </p>
   <p>