Index: trunk/BNC/src/combination/bnccomb.cpp
===================================================================
--- trunk/BNC/src/combination/bnccomb.cpp	(revision 11079)
+++ trunk/BNC/src/combination/bnccomb.cpp	(revision 11083)
@@ -1525,9 +1525,11 @@
     // 30 min and are valid for ±900 s around the reference time (TOC).
     // t_ephGlo::position() uses Runge-Kutta integration from TOC; beyond
-    // ±900 s the integration error grows unchecked and propagates into both
-    // the combined clock estimate and the SP3 position.
+    // that the integration error grows and propagates into both the
+    // combined clock estimate and the SP3 position. A margin of 60 s is
+    // allowed, as ACs switch to the next ephemeris a few seconds before its
+    // window begins (otherwise satellites drop out at every switch).
     if (corr->_eph->prn().system() == 'R') {
       double age = epoTime - corr->_eph->TOC();
-      if (fabs(age) > 900.0) {
+      if (fabs(age) > 960.0) {
         emit newMessage(QString().asprintf(
           "bncComb: skip %s, GLONASS eph age %.0fs",