diff --git a/libraries/AP_Proximity/AP_Proximity_SITL.cpp b/libraries/AP_Proximity/AP_Proximity_SITL.cpp
index 6c6d9f059d..cd364ba9a5 100644
--- a/libraries/AP_Proximity/AP_Proximity_SITL.cpp
+++ b/libraries/AP_Proximity/AP_Proximity_SITL.cpp
@@ -40,8 +40,53 @@ AP_Proximity_SITL::AP_Proximity_SITL(AP_Proximity &_frontend,
     }
 }
 
-// get distance in meters in a particular direction in degrees (0 is forward, angles increase in the clockwise direction)
-bool AP_Proximity_SITL::get_horizontal_distance(float angle_deg, float &distance) const
+// update the state of the sensor
+void AP_Proximity_SITL::update(void)
+{
+    load_fence();
+    current_loc.lat = sitl->state.latitude * 1.0e7;
+    current_loc.lng = sitl->state.longitude * 1.0e7;
+    current_loc.alt = sitl->state.altitude * 1.0e2;
+    if (fence && fence_loader.boundary_valid(fence_count->get(), fence, true)) {
+        // update distance in one sector
+        if (get_distance_to_fence(_sector_middle_deg[last_sector], _distance[last_sector])) {
+            set_status(AP_Proximity::Proximity_Good);
+            _distance_valid[last_sector] = true;
+            _angle[last_sector] = _sector_middle_deg[last_sector];
+            update_boundary_for_sector(last_sector);
+        } else {
+            _distance_valid[last_sector] = false;
+        }
+        last_sector++;
+        if (last_sector >= _num_sectors) {
+            last_sector = 0;
+        }
+    } else {
+        set_status(AP_Proximity::Proximity_NoData);        
+    }
+}
+
+void AP_Proximity_SITL::load_fence(void)
+{
+    uint32_t now = AP_HAL::millis();
+    if (now - last_load_ms < 1000) {
+        return;
+    }
+    last_load_ms = now;
+    
+    if (fence == nullptr) {
+        fence = (Vector2l *)fence_loader.create_point_array(sizeof(Vector2l));
+    }
+    if (fence == nullptr) {
+        return;
+    }
+    for (uint8_t i=0; i<fence_count->get(); i++) {
+        fence_loader.load_point_from_eeprom(i, fence[i]);
+    }
+}
+
+// get distance in meters to fence in a particular direction in degrees (0 is forward, angles increase in the clockwise direction)
+bool AP_Proximity_SITL::get_distance_to_fence(float angle_deg, float &distance) const
 {
     if (!fence_loader.boundary_valid(fence_count->get(), fence, true)) {
         return false;
@@ -70,36 +115,4 @@ bool AP_Proximity_SITL::get_horizontal_distance(float angle_deg, float &distance
     return true;
 }
 
-// update the state of the sensor
-void AP_Proximity_SITL::update(void)
-{
-    load_fence();
-    current_loc.lat = sitl->state.latitude * 1.0e7;
-    current_loc.lng = sitl->state.longitude * 1.0e7;
-    current_loc.alt = sitl->state.altitude * 1.0e2;
-    if (fence && fence_loader.boundary_valid(fence_count->get(), fence, true)) {
-        set_status(AP_Proximity::Proximity_Good);
-    } else {
-        set_status(AP_Proximity::Proximity_NoData);        
-    }
-}
-
-void AP_Proximity_SITL::load_fence(void)
-{
-    uint32_t now = AP_HAL::millis();
-    if (now - last_load_ms < 1000) {
-        return;
-    }
-    last_load_ms = now;
-    
-    if (fence == nullptr) {
-        fence = (Vector2l *)fence_loader.create_point_array(sizeof(Vector2l));
-    }
-    if (fence == nullptr) {
-        return;
-    }
-    for (uint8_t i=0; i<fence_count->get(); i++) {
-        fence_loader.load_point_from_eeprom(i, fence[i]);
-    }
-}
 #endif // CONFIG_HAL_BOARD
diff --git a/libraries/AP_Proximity/AP_Proximity_SITL.h b/libraries/AP_Proximity/AP_Proximity_SITL.h
index c21c42aedf..2d829853b8 100644
--- a/libraries/AP_Proximity/AP_Proximity_SITL.h
+++ b/libraries/AP_Proximity/AP_Proximity_SITL.h
@@ -13,10 +13,6 @@ public:
     // constructor
     AP_Proximity_SITL(AP_Proximity &_frontend, AP_Proximity::Proximity_State &_state);
 
-    // get distance in meters in a particular direction in degrees (0 is forward, clockwise)
-    // returns true on successful read and places distance in distance
-    bool get_horizontal_distance(float angle_deg, float &distance) const override;
-
     // update state
     void update(void) override;
 
@@ -27,7 +23,14 @@ private:
     uint32_t last_load_ms;
     AC_PolyFence_loader fence_loader;
     Location current_loc;
-    
+
+    // latest sector updated
+    uint8_t last_sector;
+
     void load_fence(void);
+
+    // get distance in meters to fence in a particular direction in degrees (0 is forward, angles increase in the clockwise direction)
+    bool get_distance_to_fence(float angle_deg, float &distance) const;
+
 };
 #endif // CONFIG_HAL_BOARD