Index: trunk/BNC/src/PPP_SSR_I/pppFilter.cpp
===================================================================
--- trunk/BNC/src/PPP_SSR_I/pppFilter.cpp	(revision 7851)
+++ trunk/BNC/src/PPP_SSR_I/pppFilter.cpp	(revision 7852)
@@ -295,4 +295,10 @@
   bancroft(BB, _xcBanc);
 
+  if (isnan(_xcBanc(1)) ||
+      isnan(_xcBanc(2)) ||
+      isnan(_xcBanc(3))) {
+    return failure;
+  }
+
   // Ellipsoidal Coordinates
   // ------------------------
@@ -1066,4 +1072,9 @@
       }
 
+      if (!nObs) {
+        restoreState(epoData);
+        return failure;
+      }
+
       // Prepare first-design Matrix, vector observed-computed
       // -----------------------------------------------------