AP_AHRS: remove separate calls to get delta-times for vel and ang

libraries/AP_AHRS/AP_AHRS.h

@@ -545,9 +545,7 @@ public:
     // Retrieves the corrected NED delta velocity in use by the inertial navigation
     virtual void getCorrectedDeltaVelocityNED(Vector3f& ret, float& dt) const {
         ret.zero();
-        const AP_InertialSensor &_ins = AP::ins();
+        AP::ins().get_delta_velocity(ret, dt);
-        _ins.get_delta_velocity(ret);
-        dt = _ins.get_delta_velocity_dt();
     }
 
     // create a view

libraries/AP_AHRS/AP_AHRS_DCM.cpp

@@ -150,7 +150,8 @@ AP_AHRS_DCM::matrix_update(float _G_Dt)
     for (uint8_t i=0; i<_ins.get_gyro_count(); i++) {
         if (_ins.use_gyro(i) && healthy_count < 2) {
             Vector3f dangle;
-            if (_ins.get_delta_angle(i, dangle)) {
+            float dangle_dt;
+            if (_ins.get_delta_angle(i, dangle, dangle_dt)) {
                 healthy_count++;
                 delta_angle += dangle;
             }
@@ -652,8 +653,8 @@ AP_AHRS_DCM::drift_correction(float deltat)
               each sensor, which prevents an aliasing effect
              */
             Vector3f delta_velocity;
-            _ins.get_delta_velocity(i, delta_velocity);
+            float delta_velocity_dt;
-            const float delta_velocity_dt = _ins.get_delta_velocity_dt(i);
+            _ins.get_delta_velocity(i, delta_velocity, delta_velocity_dt);
             if (delta_velocity_dt > 0) {
                 _accel_ef[i] = _dcm_matrix * (delta_velocity / delta_velocity_dt);
                 // integrate the accel vector in the earth frame between GPS readings

libraries/AP_AHRS/AP_AHRS_NavEKF.cpp

@@ -2011,9 +2011,7 @@ void AP_AHRS_NavEKF::getCorrectedDeltaVelocityNED(Vector3f& ret, float& dt) cons
         return;
     }
     ret.zero();
-    const AP_InertialSensor &_ins = AP::ins();
+    AP::ins().get_delta_velocity((uint8_t)imu_idx, ret, dt);
-    _ins.get_delta_velocity((uint8_t)imu_idx, ret);
-    dt = _ins.get_delta_velocity_dt((uint8_t)imu_idx);
     ret -= accel_bias*dt;
     ret = _dcm_matrix * get_rotation_autopilot_body_to_vehicle_body() * ret;
     ret.z += GRAVITY_MSS*dt;