diff --git a/libraries/AC_Fence/AC_Fence.cpp b/libraries/AC_Fence/AC_Fence.cpp
index 757244fe7b..4e3c5371f7 100644
--- a/libraries/AC_Fence/AC_Fence.cpp
+++ b/libraries/AC_Fence/AC_Fence.cpp
@@ -55,7 +55,7 @@ const AP_Param::GroupInfo AC_Fence::var_info[] PROGMEM = {
 };
 
 /// Default constructor.
-AC_Fence::AC_Fence(const AP_InertialNav* inav) :
+AC_Fence::AC_Fence(const AP_InertialNav& inav) :
     _inav(inav),
     _alt_max_backup(0),
     _circle_radius_backup(0),
@@ -102,7 +102,7 @@ bool AC_Fence::pre_arm_check() const
     }
 
     // if we have horizontal limits enabled, check inertial nav position is ok
-    if ((_enabled_fences & AC_FENCE_TYPE_CIRCLE)!=0 && !_inav->get_filter_status().flags.horiz_pos_abs && !_inav->get_filter_status().flags.pred_horiz_pos_abs) {
+    if ((_enabled_fences & AC_FENCE_TYPE_CIRCLE)!=0 && !_inav.get_filter_status().flags.horiz_pos_abs && !_inav.get_filter_status().flags.pred_horiz_pos_abs) {
         return false;
     }
 
@@ -132,7 +132,7 @@ uint8_t AC_Fence::check_fence()
     }
 
     // get current altitude in meters
-    float curr_alt = _inav->get_altitude() * 0.01f;
+    float curr_alt = _inav.get_altitude() * 0.01f;
 
     // altitude fence check
     if ((_enabled_fences & AC_FENCE_TYPE_ALT_MAX) != 0) {
diff --git a/libraries/AC_Fence/AC_Fence.h b/libraries/AC_Fence/AC_Fence.h
index f014fdd58f..d120643ddb 100644
--- a/libraries/AC_Fence/AC_Fence.h
+++ b/libraries/AC_Fence/AC_Fence.h
@@ -33,7 +33,7 @@ class AC_Fence
 public:
 
     /// Constructor
-    AC_Fence(const AP_InertialNav* inav);
+    AC_Fence(const AP_InertialNav& inav);
 
     /// enable - allows fence to be enabled/disabled.  Note: this does not update the eeprom saved value
     void enable(bool true_false) { _enabled = true_false; }
@@ -95,7 +95,7 @@ private:
     void clear_breach(uint8_t fence_type);
 
     // pointers to other objects we depend upon
-    const AP_InertialNav *const _inav;
+    const AP_InertialNav& _inav;
 
     // parameters
     AP_Int8         _enabled;               // top level enable/disable control