Changeset 11075 in ntrip for trunk/BNC/src/bnchelp.html

Timestamp:

Oct 5, 2026, 6:39:54 PM (9 days ago)

Author:

stuerze

Message:

ssr qc

File:

• trunk/BNC/src/bnchelp.html (modified) (5 diffs)

trunk/BNC/src/bnchelp.html

@@ -147 +147 @@
     &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; 2.8.2 <a href="#corrint">Interval</a><br>
     &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; 2.8.3 <a href="#corrport">Port</a><br>
-    &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; 2.8.4 <a href="#ssrqc">QC Logfile, QC Interval</a><br>
+    &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; 2.8.4 <a href="#ssrqc">QC Directory, QC Streams, QC Reference, QC Interval</a><br>
     &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; 2.8.4 <a href="#corrwait">Wait for Full Corr Epoch</a><br>
     &nbsp; &nbsp; &nbsp; 2.9 <a href="#syncout"><b>Feed Engine</b></a><br>
@@ -2245 +2245 @@
       The configuration reads a Broadcast Ephemeris stream and three Broadcast Correction streams in
       IGS-SSR format (SSRA00CNE1, SSRA00CHC1) and RTCM-SSR format (Galileo HAS, SSRA00EUH0; needs an account
-      at the Galileo HAS caster). An hourly QC report per stream and system is saved in the QC logfile
-      'SsrQC.txt'. The configuration can be applied to a raw file as well:
+      at the Galileo HAS caster). Hourly QC reports per system are saved in one file per stream in directory
+      'Output'. The configuration can be applied to a raw file as well:
       bnc --conf 31_SsrQC.bnc --file &lt;rawFile&gt; --key ssrQcIntr "5 min"
     </li>
@@ -5066 +5066 @@
 
   <p>
-  <h4 id="ssrqc">2.8.4 QC Logfile, QC Interval - optional</h4>
+  <h4 id="ssrqc">2.8.4 QC Directory, QC Streams, QC Reference, QC Interval - optional</h4>
   </p>
   <p>
     BNC can check the quality of all Broadcast Correction streams it decodes, in real time or when reading a raw file
-    ('--file'). Specify the full path to a 'QC Logfile' to activate this function, and select the 'QC Interval' for
-    the reports (default: 1 hour). At the end of each interval and at the end of the program, a report is written per
-    stream and system. Broadcast ephemerides must be received as well, e.g. via stream 'BCEP00BKG0'.
+    ('--file'). Specify a 'QC Directory' to activate this function. 'QC Streams' selects the streams to be checked:
+    'ALL' (default) for all decoded Broadcast Correction streams, or a comma separated list of stream names, e.g.
+    'SSRA00CNE1,SSRA00GMV0'. 'QC Reference' selects the reference of the stream comparison (see below). Select
+    the 'QC Interval' for the reports (default: 1 hour). One daily file
+    '&lt;stream&gt;_S_&lt;YYYYDDD&gt;0000_01D_QC.txt' is written per stream; at the end of each interval and at the
+    end of the program, a report per system is appended. Broadcast ephemerides must be received as well, e.g. via
+    stream 'BCEP00BKG0'.
   </p>
   <p>
@@ -5115 +5119 @@
   </p>
   <pre>
-Stream SSRA00GMV0
+=== SSR QC SSRA00GMV0 2026-10-02 11:40:00 - 2026-10-02 11:45:00 ===
   Sys Type        Epochs  Interval nom/med/max [s]  Gaps  Out-of-order  Latency med/max [s]  Sats
   G   ORBIT           47         1 /   5.0 /    5.0     0             0      11.0 /   12.0     32
@@ -5124 +5128 @@
   G ionosphere-free combination B_IF of the reference signal biases: std. dev. 0.586 m, max |B_IF| 2.058 m (32 satellites)
   G largest orbit corrections: radial 1.06 m (G11), along/cross 2.05 m (G11)
+</pre>
+  <p>
+    <b>Stream comparison:</b> In real time no ground truth is available. Therefore every 30 seconds (with a delay of 60
+    seconds, so that the corrections of all streams have arrived), the orbits and clocks of each checked stream are
+    compared with a reference, selected with option 'QC Reference':
+  </p>
+  <ul>
+    <li>'CONSENSUS' (default): per satellite the median of all other streams (at least two). A single erroneous stream
+      does not affect it, and no combination is needed. The combined stream 'INTERNAL' is not part of the consensus,
+      as it is derived from the other streams.</li>
+    <li>the name of a stream, e.g. 'INTERNAL' for the result of the combination (see section 'Combination') or the
+      stream of a selected AC. Note that an AC contributing to the combination is compared partly with itself, and
+      that the combined orbits are those of the master AC (orbit differences of the master AC are zero).</li>
+  </ul>
+  <p>
+    For each stream the satellite positions and clocks are computed from the broadcast ephemeris and the latest
+    orbit and clock corrections at the comparison epoch.
+  </p>
+  <ul>
+    <li>Orbits are only compared between streams referring to the same reference point: Antenna Phase Center (stream
+      names 'SSRA...') or Center of Mass ('SSRC...'); the differences are given in radial, along-track and cross-track
+      direction.</li>
+    <li>Clocks are referred to the reference signals by adding the ionosphere-free linear combination B_IF of the code
+      biases of the reference signals of the stream (as in the combination). Clocks of satellites without the code
+      biases of both reference signals are not compared. A common clock offset per stream, system and epoch (the
+      clock datum) is removed.</li>
+    <li>The signal-in-space difference SIS = radial orbit difference - clock difference is the part of the orbit and
+      clock difference affecting the user's range.</li>
+  </ul>
+  <p>
+    The report gives per system the RMS of the differences and, for clock and SIS, the standard deviation (STD) about
+    the mean of each satellite. Constant differences per satellite (a large RMS with a small STD) are typical between
+    ACs, as each AC realizes the satellite clocks and code biases with its own datum; a user applies the clocks and
+    biases of one AC consistently. Satellites whose RMS exceeds three times the median of the system (at least 5 cm)
+    are listed as deviating, e.g.:
+  </p>
+  <pre>
+  G comparison with consensus of the other streams (27 satellites), RMS (STD about the satellite means) [m]:
+    clock 0.689 (STD 0.008), radial 0.020, along 0.036, cross 0.022, SIS (radial - clock) 0.687 (STD 0.008)
+  G satellites deviating from the reference, RMS SIS [m]: G02(0.38) G16(0.33) G20(0.91) G26(3.36)
 </pre>
   <p>