diff --git a/tool/INS_GPS.cpp b/tool/INS_GPS.cpp
index f79327769..8e4c63b59 100644
--- a/tool/INS_GPS.cpp
+++ b/tool/INS_GPS.cpp
@@ -1139,9 +1139,13 @@ struct INS_GPS_NAV_Factory : public NAV_Factory<INS_GPS> {
   struct Checker<INS_GPS_Debug_PureInertial<T> > {
     template <class Calibration>
     static NAV *check_navdata(const Calibration &calibration){
-      return INS_GPS_NAV_Factory<
-            INS_GPS_NAVData<INS_GPS_Debug_PureInertial<T> >
-          >::generate(calibration);
+      return options.dump_stddev ?
+          INS_GPS_NAV_Factory<
+              INS_GPS_NAVData<INS_GPS_Debug_PureInertial<T, typename T::filtered_ins_t> >
+            >::generate(calibration) :
+          INS_GPS_NAV_Factory<
+              INS_GPS_NAVData<INS_GPS_Debug_PureInertial<T> >
+            >::generate(calibration);
     }
   };
 
diff --git a/tool/navigation/INS_GPS_Debug.h b/tool/navigation/INS_GPS_Debug.h
index c609addce..5991487ec 100644
--- a/tool/navigation/INS_GPS_Debug.h
+++ b/tool/navigation/INS_GPS_Debug.h
@@ -207,10 +207,10 @@ class INS_GPS_Debug_Covariance : public INS_GPS_Debug<INS_GPS> {
     }
 };
 
-template <class INS_GPS>
-class INS_GPS_Debug_PureInertial : public INS_GPS_Debug<typename INS_GPS::ins_t> {
+template <class INS_GPS, class T_INS = typename INS_GPS::ins_t>
+class INS_GPS_Debug_PureInertial : public INS_GPS_Debug<T_INS> {
   public:
-    typedef INS_GPS_Debug<typename INS_GPS::ins_t> super_t;
+    typedef INS_GPS_Debug<T_INS> super_t;
 #if defined(__GNUC__) && (__GNUC__ < 5)
     typedef typename super_t::float_t float_t;
     typedef typename super_t::vec3_t vec3_t;