AP_AHRS: support MAV_CMD_EXTERNAL_WIND_ESTIMATE

libraries/AP_AHRS/AP_AHRS.h

@@ -131,6 +131,12 @@ public:
 #endif
     }
 
+#if AP_AHRS_EXTERNAL_WIND_ESTIMATE_ENABLED
+    void set_external_wind_estimate(float speed, float direction) {
+        dcm.set_external_wind_estimate(speed, direction);
+    }
+#endif
+
     // return the parameter AHRS_WIND_MAX in metres per second
     uint8_t get_max_wind() const {
         return _wind_max;

libraries/AP_AHRS/AP_AHRS_DCM.cpp

@@ -1028,6 +1028,13 @@ void AP_AHRS_DCM::estimate_wind(void)
 #endif
 }
 
+#ifdef AP_AHRS_EXTERNAL_WIND_ESTIMATE_ENABLED
+void AP_AHRS_DCM::set_external_wind_estimate(float speed, float direction) {
+    _wind.x = -cosf(radians(direction)) * speed;
+    _wind.y = -sinf(radians(direction)) * speed;
+    _wind.z = 0;
+}
+#endif
 
 // return our current position estimate using
 // dead-reckoning or GPS

libraries/AP_AHRS/AP_AHRS_DCM.h

@@ -78,6 +78,8 @@ public:
         return true;
     }
 
+    void set_external_wind_estimate(float speed, float direction);
+
     // return an airspeed estimate if available. return true
     // if we have an estimate
     bool airspeed_estimate(float &airspeed_ret) const override;

libraries/AP_AHRS/AP_AHRS_config.h

@@ -41,3 +41,6 @@
 #define AP_AHRS_POSITION_RESET_ENABLED (BOARD_FLASH_SIZE>1024 && AP_AHRS_ENABLED)
 #endif
 
+#ifndef AP_AHRS_EXTERNAL_WIND_ESTIMATE_ENABLED
+#define AP_AHRS_EXTERNAL_WIND_ESTIMATE_ENABLED (BOARD_FLASH_SIZE>1024 && AP_AHRS_DCM_ENABLED)
+#endif