AP_AHRS: Add accessor function for EKF3 yaw alignment status

libraries/AP_AHRS/AP_AHRS_NavEKF.cpp

@@ -2549,6 +2549,44 @@ bool AP_AHRS_NavEKF::get_variances(float &velVar, float &posVar, float &hgtVar,
     return false;
 }
 
+bool AP_AHRS_NavEKF::yaw_alignment_complete(void) const
+{
+    switch (ekf_type()) {
+    case EKFType::NONE:
+        // We are not using an EKF so no data
+        return true;
+
+#if HAL_NAVEKF2_AVAILABLE
+    case EKFType::TWO: {
+        // not provided
+        return true;
+    }
+#endif
+
+#if HAL_NAVEKF3_AVAILABLE
+    case EKFType::THREE: {
+        // use EKF to get variance
+        Vector2f offset;
+        return EKF3.yawAlignmentComplete();
+    }
+#endif
+
+#if CONFIG_HAL_BOARD == HAL_BOARD_SITL
+    case EKFType::SITL:
+        // not provided
+        return true;
+#endif
+
+#if HAL_EXTERNAL_AHRS_ENABLED
+    case EKFType::EXTERNAL:
+        // not provided
+        return false;
+#endif
+    }
+
+    return false;
+}
+
 // get a source's velocity innovations.  source should be from 0 to 7 (see AP_NavEKF_Source::SourceXY)
 // returns true on success and results are placed in innovations and variances arguments
 bool AP_AHRS_NavEKF::get_vel_innovations_and_variances_for_source(uint8_t source, Vector3f &innovations, Vector3f &variances) const

libraries/AP_AHRS/AP_AHRS_NavEKF.h

@@ -282,6 +282,7 @@ public:
 
     void setTakeoffExpected(bool val);
     void setTouchdownExpected(bool val);
+    bool yaw_alignment_complete(void) const;
 
     bool getGpsGlitchStatus() const;