AP_AHRS: removed create() method for objects

See discussion here:

  https://github.com/ArduPilot/ardupilot/issues/7331

we were getting some uninitialised variables. While it only showed up in
AP_SbusOut, it means we can't be sure it won't happen on other objects,
so safest to remove the approach

Thanks to assistance from Lucas, Peter and Francisco

libraries/AP_AHRS/AP_AHRS_DCM.h

@@ -23,11 +23,38 @@
 
 class AP_AHRS_DCM : public AP_AHRS {
 public:
-    static AP_AHRS_DCM create(AP_InertialSensor &ins, AP_Baro &baro, AP_GPS &gps) {
-        return AP_AHRS_DCM{ins, baro, gps};
-    }
+    AP_AHRS_DCM(AP_InertialSensor &ins, AP_Baro &baro, AP_GPS &gps)
+        : AP_AHRS(ins, baro, gps)
+        , _omega_I_sum_time(0.0f)
+        , _renorm_val_sum(0.0f)
+        , _renorm_val_count(0)
+        , _error_rp(1.0f)
+        , _error_yaw(1.0f)
+        , _gps_last_update(0)
+        , _ra_deltat(0.0f)
+        , _ra_sum_start(0)
+        , _last_declination(0.0f)
+        , _mag_earth(1, 0)
+        , _have_gps_lock(false)
+        , _last_lat(0)
+        , _last_lng(0)
+        , _position_offset_north(0.0f)
+        , _position_offset_east(0.0f)
+        , _have_position(false)
+        , _last_wind_time(0)
+        , _last_airspeed(0.0f)
+        , _last_consistent_heading(0)
+        , _imu1_weight(0.5f)
+        , _last_failure_ms(0)
+        , _last_startup_ms(0)
+    {
+        _dcm_matrix.identity();
 
-    constexpr AP_AHRS_DCM(AP_AHRS_DCM &&other) = default;
+        // these are experimentally derived from the simulator
+        // with large drift levels
+        _ki = 0.0087f;
+        _ki_yaw = 0.01f;
+    }
 
     /* Do not allow copies */
     AP_AHRS_DCM(const AP_AHRS_DCM &other) = delete;
@@ -93,40 +120,6 @@ public:
     // time that the AHRS has been up
     uint32_t uptime_ms() const override;
 
-protected:
-    AP_AHRS_DCM(AP_InertialSensor &ins, AP_Baro &baro, AP_GPS &gps)
-        : AP_AHRS(ins, baro, gps)
-        , _omega_I_sum_time(0.0f)
-        , _renorm_val_sum(0.0f)
-        , _renorm_val_count(0)
-        , _error_rp(1.0f)
-        , _error_yaw(1.0f)
-        , _gps_last_update(0)
-        , _ra_deltat(0.0f)
-        , _ra_sum_start(0)
-        , _last_declination(0.0f)
-        , _mag_earth(1, 0)
-        , _have_gps_lock(false)
-        , _last_lat(0)
-        , _last_lng(0)
-        , _position_offset_north(0.0f)
-        , _position_offset_east(0.0f)
-        , _have_position(false)
-        , _last_wind_time(0)
-        , _last_airspeed(0.0f)
-        , _last_consistent_heading(0)
-        , _imu1_weight(0.5f)
-        , _last_failure_ms(0)
-        , _last_startup_ms(0)
-    {
-        _dcm_matrix.identity();
-
-        // these are experimentally derived from the simulator
-        // with large drift levels
-        _ki = 0.0087f;
-        _ki_yaw = 0.01f;
-    }
-
 private:
     float _ki;
     float _ki_yaw;

libraries/AP_AHRS/AP_AHRS_NavEKF.h

@@ -43,15 +43,9 @@ public:
         FLAG_ALWAYS_USE_EKF = 0x1,
     };
 
-    static AP_AHRS_NavEKF create(AP_InertialSensor &ins,
-                                 AP_Baro &baro,
-                                 AP_GPS &gps,
-                                 NavEKF2 &_EKF2, NavEKF3 &_EKF3,
-                                 Flags flags = FLAG_NONE) {
-        return AP_AHRS_NavEKF{ins, baro, gps, _EKF2, _EKF3, flags};
-    }
-
-    constexpr AP_AHRS_NavEKF(AP_AHRS_NavEKF &&other) = default;
+    // Constructor
+    AP_AHRS_NavEKF(AP_InertialSensor &ins, AP_Baro &baro, AP_GPS &gps,
+                   NavEKF2 &_EKF2, NavEKF3 &_EKF3, Flags flags = FLAG_NONE);
 
     /* Do not allow copies */
     AP_AHRS_NavEKF(const AP_AHRS_NavEKF &other) = delete;
@@ -302,10 +296,5 @@ private:
     uint32_t _last_body_odm_update_ms = 0;
     void update_SITL(void);
 #endif    
-
-private:
-    // Constructor
-    AP_AHRS_NavEKF(AP_InertialSensor &ins, AP_Baro &baro, AP_GPS &gps,
-                   NavEKF2 &_EKF2, NavEKF3 &_EKF3, Flags flags = FLAG_NONE);
 };
 #endif

libraries/AP_AHRS/examples/AHRS_Test/AHRS_Test.cpp

@@ -14,22 +14,22 @@ void loop();
 const AP_HAL::HAL& hal = AP_HAL::get_HAL();
 
 
-static AP_BoardConfig board_config = AP_BoardConfig::create();
-static AP_InertialSensor ins = AP_InertialSensor::create();
+static AP_BoardConfig board_config;
+static AP_InertialSensor ins;
 
-static Compass compass = Compass::create();
+static Compass compass;
 
-static AP_GPS gps = AP_GPS::create();
-static AP_Baro barometer = AP_Baro::create();
-static AP_SerialManager serial_manager = AP_SerialManager::create();
+static AP_GPS gps;
+static AP_Baro barometer;
+static AP_SerialManager serial_manager;
 
 class DummyVehicle {
 public:
-    RangeFinder sonar = RangeFinder::create(serial_manager, ROTATION_PITCH_270);
-    NavEKF2 EKF2 = NavEKF2::create(&ahrs, barometer, sonar);
-    NavEKF3 EKF3 = NavEKF3::create(&ahrs, barometer, sonar);
-    AP_AHRS_NavEKF ahrs = AP_AHRS_NavEKF::create(ins, barometer, gps, EKF2, EKF3,
-                                                 AP_AHRS_NavEKF::FLAG_ALWAYS_USE_EKF);
+    RangeFinder sonar{serial_manager, ROTATION_PITCH_270};
+    NavEKF2 EKF2{&ahrs, barometer, sonar};
+    NavEKF3 EKF3{&ahrs, barometer, sonar};
+    AP_AHRS_NavEKF ahrs{ins, barometer, gps, EKF2, EKF3,
+            AP_AHRS_NavEKF::FLAG_ALWAYS_USE_EKF};
 };
 
 static DummyVehicle vehicle;