ArduCopter: respect yaw orientation on LAND

ArduCopter/mode.cpp

@@ -541,6 +541,9 @@ void Copter::Mode::land_run_horizontal_control()
 
         // get pilot's desired yaw rate
         target_yaw_rate = get_pilot_desired_yaw_rate(channel_yaw->get_control_in());
+        if (!is_zero(target_yaw_rate)) {
+            auto_yaw.set_mode(AUTO_YAW_HOLD);
+        }
     }
 
 #if PRECISION_LANDING == ENABLED
@@ -590,9 +593,14 @@ void Copter::Mode::land_run_horizontal_control()
         }
     }
 
-
     // call attitude controller
-    attitude_control->input_euler_angle_roll_pitch_euler_rate_yaw(nav_roll, nav_pitch, target_yaw_rate);
+    if (auto_yaw.mode() == AUTO_YAW_HOLD) {
+        // roll & pitch from waypoint controller, yaw rate from pilot
+        attitude_control->input_euler_angle_roll_pitch_euler_rate_yaw(nav_roll, nav_pitch, target_yaw_rate);
+    } else {
+        // roll, pitch from waypoint controller, yaw heading from auto_heading()
+        attitude_control->input_euler_angle_roll_pitch_yaw(nav_roll, nav_pitch, auto_yaw.yaw(), true);
+    }
 }
 
 float Copter::Mode::throttle_hover() const