AP_Compass: added set_board_orientation() method

libraries/AP_Compass/AP_Compass_HMC5843.cpp

@@ -322,8 +322,13 @@ bool AP_Compass_HMC5843::read()
     if (product_id == AP_COMPASS_TYPE_HMC5883L) {
         rot_mag.rotate(ROTATION_YAW_90);
     }
+
+    // add components orientation
     rot_mag.rotate(_orientation);
 
+    // add in board orientation
+    rot_mag.rotate(_board_orientation);
+
     rot_mag += _offset.get();
     mag_x = rot_mag.x;
     mag_y = rot_mag.y;

libraries/AP_Compass/AP_Compass_PX4.cpp

@@ -64,7 +64,7 @@ bool AP_Compass_PX4::read(void)
     _sum /= _count;
     _sum *= 1000;
     _sum.rotate(_orientation);
-
+    _sum.rotate(_board_orientation);
     _sum += _offset.get();
 
     mag_x = _sum.x;

libraries/AP_Compass/Compass.h

@@ -123,6 +123,11 @@ public:
 
     static const struct AP_Param::GroupInfo var_info[];
 
+    // set overall board orientation
+    void set_board_orientation(enum Rotation orientation) {
+        _board_orientation = orientation;
+    }
+
 protected:
     enum Rotation _orientation;
     AP_Vector3f _offset;
@@ -137,5 +142,8 @@ protected:
     static const uint8_t _mag_history_size = 20;
     uint8_t _mag_history_index;
     Vector3i _mag_history[_mag_history_size];
+
+    // board orientation from AHRS
+    enum Rotation _board_orientation;
 };
 #endif