AP_AHRS: Add accessor function for body frame airspeed vector

libraries/AP_AHRS/AP_AHRS.h

@@ -265,6 +265,12 @@ public:
         return true;
     }
 
+    // return estimate of true airspeed vector in body frame in m/s
+    // returns false if estimate is unavailable
+    virtual bool airspeed_vector_true(Vector3f &vec) const WARN_IF_UNUSED {
+        return false;
+    }
+
     // return a synthetic airspeed estimate (one derived from sensors
     // other than an actual airspeed sensor), if available. return
     // true if we have a synthetic airspeed.  ret will not be modified

libraries/AP_AHRS/AP_AHRS_NavEKF.cpp

@@ -561,6 +561,31 @@ bool AP_AHRS_NavEKF::airspeed_estimate(float &airspeed_ret) const
     return AP_AHRS_DCM::airspeed_estimate(get_active_airspeed_index(), airspeed_ret);
 }
 
+// return estimate of true airspeed vector in body frame in m/s
+// returns false if estimate is unavailable
+bool AP_AHRS_NavEKF::airspeed_vector_true(Vector3f &vec) const
+{
+    switch (active_EKF_type()) {
+    case EKFType::NONE:
+        break;
+#if HAL_NAVEKF2_AVAILABLE
+    case EKFType::TWO:
+        return EKF2.getAirSpdVec(-1, vec);
+#endif
+
+#if HAL_NAVEKF3_AVAILABLE
+    case EKFType::THREE:
+        return EKF3.getAirSpdVec(-1, vec);
+#endif
+
+#if CONFIG_HAL_BOARD == HAL_BOARD_SITL
+    case EKFType::SITL:
+        break;
+#endif
+    }
+    return false;
+}
+
 // true if compass is being used
 bool AP_AHRS_NavEKF::use_compass(void)
 {

libraries/AP_AHRS/AP_AHRS_NavEKF.h

@@ -96,6 +96,10 @@ public:
     // if we have an estimate
     bool airspeed_estimate(float &airspeed_ret) const override;
 
+    // return estimate of true airspeed vector in body frame in m/s
+    // returns false if estimate is unavailable
+    bool airspeed_vector_true(Vector3f &vec) const override;
+
     // true if compass is being used
     bool use_compass() override;