Index: trunk/BNS/bnseph.cpp
===================================================================
--- trunk/BNS/bnseph.cpp	(revision 895)
+++ trunk/BNS/bnseph.cpp	(revision 896)
@@ -390,5 +390,5 @@
     dtClk += (GPSweek - _GPSweek) * secPerWeek;
   }
-  xc(4) = _tau + _gamma * dtClk / 86400.0;
-}
-
+  xc(4) = -_tau + _gamma * dtClk / 86400.0;
+}
+