diff --git a/libraries/AP_Proximity/AP_Proximity_TeraRangerTower.cpp b/libraries/AP_Proximity/AP_Proximity_TeraRangerTower.cpp
index ab82f90d98..cef56eb661 100644
--- a/libraries/AP_Proximity/AP_Proximity_TeraRangerTower.cpp
+++ b/libraries/AP_Proximity/AP_Proximity_TeraRangerTower.cpp
@@ -92,14 +92,14 @@ bool AP_Proximity_TeraRangerTower::read_sensor_data()
 }
 
 // process reply
-void AP_Proximity_TeraRangerTower::update_sector_data(int16_t angle_deg, uint16_t distance_cm)
+void AP_Proximity_TeraRangerTower::update_sector_data(int16_t angle_deg, uint16_t distance_mm)
 {
     // Get location on 3-D boundary based on angle to the object
     const AP_Proximity_Boundary_3D::Face face = boundary.get_face(angle_deg);
-    if ((distance_cm != 0xffff) && !ignore_reading(angle_deg, distance_cm * 0.001f, false)) {
-        boundary.set_face_attributes(face, angle_deg, ((float) distance_cm) / 1000);
+    if ((distance_mm != 0xffff) && !ignore_reading(angle_deg, distance_mm * 0.001f, false)) {
+        boundary.set_face_attributes(face, angle_deg, ((float) distance_mm) / 1000);
         // update OA database
-        database_push(angle_deg, ((float) distance_cm) / 1000);
+        database_push(angle_deg, ((float) distance_mm) / 1000);
     } else {
         boundary.reset_face(face);
     }
diff --git a/libraries/AP_Proximity/AP_Proximity_TeraRangerTower.h b/libraries/AP_Proximity/AP_Proximity_TeraRangerTower.h
index bcbd40baad..35006cad84 100644
--- a/libraries/AP_Proximity/AP_Proximity_TeraRangerTower.h
+++ b/libraries/AP_Proximity/AP_Proximity_TeraRangerTower.h
@@ -23,7 +23,7 @@ private:
 
     // check and process replies from sensor
     bool read_sensor_data();
-    void update_sector_data(int16_t angle_deg, uint16_t distance_cm);
+    void update_sector_data(int16_t angle_deg, uint16_t distance_mm);
 
     // reply related variables
     uint8_t buffer[20]; // buffer where to store data from serial
diff --git a/libraries/AP_Proximity/AP_Proximity_TeraRangerTowerEvo.cpp b/libraries/AP_Proximity/AP_Proximity_TeraRangerTowerEvo.cpp
index 29a911b761..700694e810 100644
--- a/libraries/AP_Proximity/AP_Proximity_TeraRangerTowerEvo.cpp
+++ b/libraries/AP_Proximity/AP_Proximity_TeraRangerTowerEvo.cpp
@@ -145,16 +145,16 @@ bool AP_Proximity_TeraRangerTowerEvo::read_sensor_data()
 }
 
 // process reply
-void AP_Proximity_TeraRangerTowerEvo::update_sector_data(int16_t angle_deg, uint16_t distance_cm)
+void AP_Proximity_TeraRangerTowerEvo::update_sector_data(int16_t angle_deg, uint16_t distance_mm)
 {
     // Get location on 3-D boundary based on angle to the object
     const AP_Proximity_Boundary_3D::Face face = boundary.get_face(angle_deg);
     //check for target too far, target too close and sensor not connected
-    const bool valid = (distance_cm != 0xffff) && (distance_cm > 0x0001);
-    if (valid && !ignore_reading(angle_deg, distance_cm * 0.001f, false)) {
-        boundary.set_face_attributes(face, angle_deg, ((float) distance_cm) / 1000);
+    const bool valid = (distance_mm != 0xffff) && (distance_mm > 0x0001);
+    if (valid && !ignore_reading(angle_deg, distance_mm * 0.001f, false)) {
+        boundary.set_face_attributes(face, angle_deg, ((float) distance_mm) / 1000);
         // update OA database
-        database_push(angle_deg, ((float) distance_cm) / 1000);
+        database_push(angle_deg, ((float) distance_mm) / 1000);
     } else {
         boundary.reset_face(face);
     }
diff --git a/libraries/AP_Proximity/AP_Proximity_TeraRangerTowerEvo.h b/libraries/AP_Proximity/AP_Proximity_TeraRangerTowerEvo.h
index 59261bf15e..4b12d3fab6 100644
--- a/libraries/AP_Proximity/AP_Proximity_TeraRangerTowerEvo.h
+++ b/libraries/AP_Proximity/AP_Proximity_TeraRangerTowerEvo.h
@@ -25,7 +25,7 @@ private:
     // check and process replies from sensor
     void initialise_modes();
     bool read_sensor_data();
-    void update_sector_data(int16_t angle_deg, uint16_t distance_cm);
+    void update_sector_data(int16_t angle_deg, uint16_t distance_mm);
     void set_mode(const uint8_t *c, int length);
 
     enum InitState {