Index: /trunk/BNC/src/RTCM/GPSDecoder.cpp
===================================================================
--- /trunk/BNC/src/RTCM/GPSDecoder.cpp	(revision 4441)
+++ /trunk/BNC/src/RTCM/GPSDecoder.cpp	(revision 4442)
@@ -140,6 +140,8 @@
     case GNSSENTRY_SNR:     str[0] = 'S'; break;
   }
-  str[1] = _codetype[iEntry][0];
-  str[2] = _codetype[iEntry][1];
-  return str;
+  if (_codetype[iEntry]) {
+    str[1] = _codetype[iEntry][0];
+    str[2] = _codetype[iEntry][1];
+  }
+  return str.trimmed();
 }