diff --git a/libraries/AP_OSD/AP_OSD.cpp b/libraries/AP_OSD/AP_OSD.cpp
index 3293f0fdbc..7495374a44 100644
--- a/libraries/AP_OSD/AP_OSD.cpp
+++ b/libraries/AP_OSD/AP_OSD.cpp
@@ -121,6 +121,13 @@ const AP_Param::GroupInfo AP_OSD::var_info[] = {
     // @User: Standard
     AP_GROUPINFO("_W_BATVOLT", 14, AP_OSD, warn_batvolt, 10.0f),
 
+    // @Param: _UNITS
+    // @DisplayName: Display Units
+    // @Description: Sets the units to use in displaying items
+    // @Values: 0:Metric,1:Imperial
+    // @User: Standard
+    AP_GROUPINFO("_UNITS", 15, AP_OSD, units, 0),
+    
     AP_GROUPEND
 };
 
diff --git a/libraries/AP_OSD/AP_OSD.h b/libraries/AP_OSD/AP_OSD.h
index f4d44e9063..73f67f85ff 100644
--- a/libraries/AP_OSD/AP_OSD.h
+++ b/libraries/AP_OSD/AP_OSD.h
@@ -103,8 +103,18 @@ private:
 
     bool check_option(uint32_t option);
 
-    char u_icon(uint16_t unit_type);
-    float u_scale(uint16_t unit_type, float value);
+    enum unit_type {
+        ALTITUDE=0,
+        SPEED=1,
+        VSPEED=2,
+        DISTANCE=3,
+        DISTANCE_LONG=4,
+        TEMPERATURE=5,
+        UNIT_TYPE_LAST=6,
+    };
+    
+    char u_icon(enum unit_type unit);
+    float u_scale(enum unit_type unit, float value);
 
     void draw_altitude(uint8_t x, uint8_t y);
     void draw_bat_volt(uint8_t x, uint8_t y);
@@ -136,17 +146,6 @@ private:
 
     void draw_gps_latitude(uint8_t x, uint8_t y);
     void draw_gps_longitude(uint8_t x, uint8_t y);
-
-    enum {
-        ALTITUDE=0,
-        SPEED=1,
-        VSPEED=2,
-        DISTANCE=3,
-        DISTANCE_LONG=4,
-        TEMPERATURE=5,
-        UNIT_LAST=6,
-    };
-
 };
 
 class AP_OSD {
diff --git a/libraries/AP_OSD/AP_OSD_Screen.cpp b/libraries/AP_OSD/AP_OSD_Screen.cpp
index 22fff9c191..9567cdd4b2 100644
--- a/libraries/AP_OSD/AP_OSD_Screen.cpp
+++ b/libraries/AP_OSD/AP_OSD_Screen.cpp
@@ -230,40 +230,73 @@ bool AP_OSD_Screen::check_option(uint32_t option)
     return (osd->options & option) != 0;
 }
 
-char AP_OSD_Screen::u_icon(uint16_t unit)
+/*
+  get the right units icon given a unit
+ */
+char AP_OSD_Screen::u_icon(enum unit_type unit)
 {
-    static const char icons[UNIT_LAST][AP_OSD::UNITS_LAST] = {
-        {(char)SYM_ALT_M, (char)SYM_ALT_FT},  //ALTITUDE
-        {(char)SYM_KMH, (char)SYM_MPH},       //SPEED
-        {(char)SYM_MS, (char)SYM_FS},         //VSPEED
-        {(char)SYM_M, (char)SYM_FT},          //DISTANCE
-        {(char)SYM_KM, (char)SYM_MI},         //DISTANCE_LONG
-        {(char)SYM_DEGREES_C, (char)SYM_DEGREES_F}//TEMPERATURE
+    static const char icons_metric[UNIT_TYPE_LAST] {
+        (char)SYM_ALT_M,    //ALTITUDE
+        (char)SYM_KMH,      //SPEED
+        (char)SYM_MS,       //VSPEED
+        (char)SYM_M,        //DISTANCE
+        (char)SYM_KM,       //DISTANCE_LONG
+        (char)SYM_DEGREES_C //TEMPERATURE
     };
-    return icons[unit][osd->units];
+    static const char icons_imperial[UNIT_TYPE_LAST] {
+        (char)SYM_ALT_FT,   //ALTITUDE
+        (char)SYM_MPH,      //SPEED
+        (char)SYM_FS,       //VSPEED
+        (char)SYM_FT,       //DISTANCE
+        (char)SYM_MI,       //DISTANCE_LONG
+        (char)SYM_DEGREES_F //TEMPERATURE
+    };
+    static const char *icons[AP_OSD::UNITS_LAST] = {
+        icons_metric,
+        icons_imperial
+    };
+    return icons[constrain_int16(osd->units, 0, AP_OSD::UNITS_LAST-1)][unit];
 }
 
-float AP_OSD_Screen::u_scale(uint16_t unit, float value)
+/*
+  scale a value for the user selected units
+ */
+float AP_OSD_Screen::u_scale(enum unit_type unit, float value)
 {
-    static const float scale[UNIT_LAST][AP_OSD::UNITS_LAST] = {
-        {1.0f, 3.28084f},             //ALTITUDE
-        {3.6f, 2.23694f},             //SPEED
-        {1.0f, 3.28084f},             //VSPEED
-        {1.0f, 3.28084f},             //DISTANCE
-        {1.0f/1000.0f, 1.0f/1609.34f},//DISTANCE_LONG
-        {1.0f, 1.8f}                  //TEMPERATURE
+    static const float scale_metric[UNIT_TYPE_LAST] = {
+        1.0,       //ALTITUDE
+        3.6,       //SPEED
+        1.0,       //VSPEED
+        1.0,       //DISTANCE
+        1.0/1000,  //DISTANCE_LONG
+        1.0,       //TEMPERATURE
     };
-
-    static const float offset[UNIT_LAST][AP_OSD::UNITS_LAST] = {
-        {0.0f, 0.0f},          //ALTITUDE
-        {0.0f, 0.0f},          //SPEED
-        {0.0f, 0.0f},          //VSPEED
-        {0.0f, 0.0f},          //DISTANCE
-        {0.0f, 0.0f},          //DISTANCE_LONG
-        {0.0f, 32.0f},         //TEMPERATURE
+    static const float scale_imperial[UNIT_TYPE_LAST] = {
+        3.28084,     //ALTITUDE
+        2.23694,     //SPEED
+        3.28084,     //VSPEED
+        3.28084,     //DISTANCE
+        1.0/1609.34, //DISTANCE_LONG
+        1.8,         //TEMPERATURE
     };
-
-    return value * scale[unit][osd->units] + offset[unit][osd->units];
+    static const float offset_imperial[UNIT_TYPE_LAST] = {
+        0.0,          //ALTITUDE
+        0.0,          //SPEED
+        0.0,          //VSPEED
+        0.0,          //DISTANCE
+        0.0,          //DISTANCE_LONG
+        32.0,         //TEMPERATURE
+    };
+    static const float *scale[AP_OSD::UNITS_LAST] = {
+        scale_metric,
+        scale_imperial
+    };
+    static const float *offsets[AP_OSD::UNITS_LAST] = {
+        nullptr,
+        offset_imperial
+    };
+    uint8_t units = constrain_int16(osd->units, 0, AP_OSD::UNITS_LAST-1);
+    return value * scale[units][unit] + (offsets[units]?offsets[units][unit]:0);
 }
 
 void AP_OSD_Screen::draw_altitude(uint8_t x, uint8_t y)