Index: /branches/BNC_2.13/src/PPP/pppFilter.cpp
===================================================================
--- /branches/BNC_2.13/src/PPP/pppFilter.cpp	(revision 9999)
+++ /branches/BNC_2.13/src/PPP/pppFilter.cpp	(revision 10000)
@@ -266,4 +266,8 @@
     if (iObs == -1) {
       LOG << " number of observations == " << iObs + 1 << "\n";
+      if (preProcessing) {
+        _obsPool->setRefSatChangeRequired(sys, true);
+        return success;
+      }      
       return failure;
     }
@@ -761,8 +765,12 @@
     }
 
-    if (!iObs) {
+    if (!(iObs+1)) {
       continue;
     }
-    _datumTrafo->updateIndices(sys, iObs + 1); //LOG << "AA Ncols/Nrows: " << AA.Ncols() << "/" << AA.Nrows() << "  nPar: "  << nPar << endl;    //LOG << "AA.SubMatrix(1 .. " << iObs+1 << " , 1 .. " <<  nPar << ")" << endl;
+    _datumTrafo->updateIndices(sys, iObs + 1);
+#ifdef BNC_DEBUG_PPP
+    LOG << "AA Ncols/Nrows: " << AA.Ncols() << "/" << AA.Nrows() << "  nPar: "  << nPar << endl;
+    LOG << "AA.SubMatrix(1 .. " << iObs+1 << " , 1 .. " <<  nPar << ")" << endl;
+#endif
     if (_datumTrafo->prepareAA(AA.SubMatrix(1, iObs + 1, 1, nPar), 2)
         != success) {