AP_AHRS: added optional skip_ins_update to AHRS::update()

avoid the ins update if already done in copter fast_loop()

libraries/AP_AHRS/AP_AHRS.h

@@ -210,7 +210,7 @@ public:
     }
 
     // Methods
-    virtual void update(void) = 0;
+    virtual void update(bool skip_ins_update=false) = 0;
 
     // report any reason for why the backend is refusing to initialise
     virtual const char *prearm_failure_reason(void) const {

libraries/AP_AHRS/AP_AHRS_DCM.cpp

@@ -47,7 +47,7 @@ AP_AHRS_DCM::reset_gyro_drift(void)
 
 // run a full DCM update round
 void
-AP_AHRS_DCM::update(void)
+AP_AHRS_DCM::update(bool skip_ins_update)
 {
     float delta_t;
 
@@ -55,8 +55,10 @@ AP_AHRS_DCM::update(void)
         _last_startup_ms = AP_HAL::millis();
     }
 
-    // tell the IMU to grab some data
-    _ins.update();
+    if (!skip_ins_update) {
+        // tell the IMU to grab some data
+        _ins.update();
+    }
 
     // ask the IMU how much time this sensor reading represents
     delta_t = _ins.get_delta_time();

libraries/AP_AHRS/AP_AHRS_DCM.h

@@ -78,7 +78,7 @@ public:
     void reset_gyro_drift() override;
 
     // Methods
-    void            update() override;
+    void            update(bool skip_ins_update=false) override;
     void            reset(bool recover_eulers = false) override;
 
     // reset the current attitude, used on new IMU calibration

libraries/AP_AHRS/AP_AHRS_NavEKF.cpp

@@ -79,13 +79,13 @@ void AP_AHRS_NavEKF::reset_gyro_drift(void)
     EKF3.resetGyroBias();
 }
 
-void AP_AHRS_NavEKF::update(void)
+void AP_AHRS_NavEKF::update(bool skip_ins_update)
 {
     // EKF1 is no longer supported - handle case where it is selected
     if (_ekf_type == 1) {
         _ekf_type.set(2);
     }
-    update_DCM();
+    update_DCM(skip_ins_update);
     update_EKF2();
     update_EKF3();
 #if CONFIG_HAL_BOARD == HAL_BOARD_SITL
@@ -103,11 +103,11 @@ void AP_AHRS_NavEKF::update(void)
 
     if (_view != nullptr) {
         // update optional alternative attitude view
-        _view->update();
+        _view->update(skip_ins_update);
     }
 }
 
-void AP_AHRS_NavEKF::update_DCM(void)
+void AP_AHRS_NavEKF::update_DCM(bool skip_ins_update)
 {
     // we need to restore the old DCM attitude values as these are
     // used internally in DCM to calculate error values for gyro drift
@@ -117,7 +117,7 @@ void AP_AHRS_NavEKF::update_DCM(void)
     yaw = _dcm_attitude.z;
     update_cd_values();
 
-    AP_AHRS_DCM::update();
+    AP_AHRS_DCM::update(skip_ins_update);
 
     // keep DCM attitude available for get_secondary_attitude()
     _dcm_attitude(roll, pitch, yaw);

libraries/AP_AHRS/AP_AHRS_NavEKF.h

@@ -59,7 +59,7 @@ public:
     //  should be called if gyro offsets are recalculated
     void reset_gyro_drift() override;
 
-    void            update() override;
+    void            update(bool skip_ins_update=false) override;
     void            reset(bool recover_eulers = false) override;
 
     // reset the current attitude, used on new IMU calibration
@@ -268,7 +268,7 @@ private:
     Flags _ekf_flags;
 
     uint8_t ekf_type(void) const;
-    void update_DCM(void);
+    void update_DCM(bool skip_ins_update);
     void update_EKF2(void);
     void update_EKF3(void);
 

libraries/AP_AHRS/AP_AHRS_View.cpp

@@ -44,7 +44,7 @@ AP_AHRS_View::AP_AHRS_View(AP_AHRS &_ahrs, enum Rotation _rotation) :
 }
 
 // update state
-void AP_AHRS_View::update(void)
+void AP_AHRS_View::update(bool skip_ins_update)
 {
     rot_body_to_ned = ahrs.get_rotation_body_to_ned();
     gyro = ahrs.get_gyro();

libraries/AP_AHRS/AP_AHRS_View.h

@@ -29,7 +29,7 @@ public:
     AP_AHRS_View(AP_AHRS &ahrs, enum Rotation rotation);
 
     // update state
-    void update(void);
+    void update(bool skip_ins_update=false);
 
     // empty virtual destructor
     virtual ~AP_AHRS_View() {}