diff --git a/libraries/AP_Proximity/AP_Proximity_Backend.h b/libraries/AP_Proximity/AP_Proximity_Backend.h
index efd71b1598..48422a918d 100644
--- a/libraries/AP_Proximity/AP_Proximity_Backend.h
+++ b/libraries/AP_Proximity/AP_Proximity_Backend.h
@@ -24,7 +24,7 @@
 
 #define PROXIMITY_GND_DETECT_THRESHOLD 1.0f // set ground detection threshold to be 1 meters
 #define PROXIMITY_ALT_DETECT_TIMEOUT_MS 500 // alt readings should arrive within this much time
-#define PROXIMITY_BOUNDARY_3D_TIMEOUT_MS 1000 // we should check the 3D boundary faces after every this many ms
+#define PROXIMITY_BOUNDARY_3D_TIMEOUT_MS 750 // we should check the 3D boundary faces after every this many ms
 
 class AP_Proximity_Backend
 {
diff --git a/libraries/AP_Proximity/AP_Proximity_Boundary_3D.h b/libraries/AP_Proximity/AP_Proximity_Boundary_3D.h
index 1d8b8e1a30..b9f2c01702 100644
--- a/libraries/AP_Proximity/AP_Proximity_Boundary_3D.h
+++ b/libraries/AP_Proximity/AP_Proximity_Boundary_3D.h
@@ -29,7 +29,7 @@
 #define PROXIMITY_BOUNDARY_DIST_MIN   0.6f    // minimum distance for a boundary point.  This ensures the object avoidance code doesn't think we are outside the boundary.
 #define PROXIMITY_BOUNDARY_DIST_DEFAULT 100   // if we have no data for a sector, boundary is placed 100m out
 #define PROXIMITY_FILT_RESET_TIME     1000    // reset filter if last distance was pushed more than this many ms away
-#define PROXIMITY_FACE_RESET_MS       1250    // face will be reset if not updated within this many ms
+#define PROXIMITY_FACE_RESET_MS       1000    // face will be reset if not updated within this many ms
 
 class AP_Proximity_Boundary_3D
 {
diff --git a/libraries/AP_Proximity/AP_Proximity_MAV.cpp b/libraries/AP_Proximity/AP_Proximity_MAV.cpp
index 18f765a363..2936a315ae 100644
--- a/libraries/AP_Proximity/AP_Proximity_MAV.cpp
+++ b/libraries/AP_Proximity/AP_Proximity_MAV.cpp
@@ -23,7 +23,7 @@
 extern const AP_HAL::HAL& hal;
 
 #define PROXIMITY_MAV_TIMEOUT_MS    500 // distance messages must arrive within this many milliseconds
-#define PROXIMITY_TIMESTAMP_MSG_TIMEOUT_MS  50  // boundary will be reset if mavlink message does not arrive within this many milliseconds
+#define PROXIMITY_TIMESTAMP_MSG_TIMEOUT_MS  50  // obstacles will be transferred from temp boundary to actual boundary if mavlink message does not arrive within this many milliseconds
 
 // update the state of the sensor
 void AP_Proximity_MAV::update(void)
@@ -85,8 +85,6 @@ void AP_Proximity_MAV::handle_distance_sensor_msg(const mavlink_message_t &msg)
         // we will add on to the last fence if the time stamp is the same
         // provided we got the new obstacle in less than PROXIMITY_TIMESTAMP_MSG_TIMEOUT_MS
         if ((previous_msg_timestamp != _last_msg_update_timestamp_ms) || (time_diff > PROXIMITY_TIMESTAMP_MSG_TIMEOUT_MS)) {
-            // cleared fence back to defaults since we have a new timestamp
-            boundary.reset();
             // push data from temp boundary to the main 3-D proximity boundary
             temp_boundary.update_3D_boundary(boundary);
             // clear temp boundary for new data
@@ -231,12 +229,8 @@ void AP_Proximity_MAV::handle_obstacle_distance_3d_msg(const mavlink_message_t &
         return;
     }
 
-    // we will add on to the last fence if the time stamp is the same
-    // provided we got the new obstacle in less than PROXIMITY_TIMESTAMP_MSG_TIMEOUT_MS
     if ((previous_msg_timestamp != _last_msg_update_timestamp_ms) || (time_diff > PROXIMITY_TIMESTAMP_MSG_TIMEOUT_MS)) {
-        // cleared fence back to defaults since we have a new timestamp
-        boundary.reset();
-        // push data from temp boundary to the main 3-D proximity boundary
+        // push data from temp boundary to the main 3-D proximity boundary because a new timestamp has arrived
         temp_boundary.update_3D_boundary(boundary);
         // clear temp boundary for new data
         temp_boundary.reset();