diff --git a/EKF/covariance.cpp b/EKF/covariance.cpp
index 11a2deb051..ca34817370 100644
--- a/EKF/covariance.cpp
+++ b/EKF/covariance.cpp
@@ -59,7 +59,6 @@ void Ekf::initialiseCovariance()
 	Vector3f rot_vec_var;
 	rot_vec_var.setAll(sq(_params.initial_tilt_err));
 
-	// update the quaternion state covariances
 	initialiseQuatCovariances(rot_vec_var);
 
 	// velocity
@@ -96,8 +95,6 @@ void Ekf::initialiseCovariance()
 	// record IMU bias state covariance reset time - used to prevent resets being performed too often
 	_last_imu_bias_cov_reset_us = _imu_sample_delayed.time_us;
 
-	// variances for optional states
-
 	// earth frame and body frame magnetic field
 	// set to observation variance
 	for (uint8_t index = 16; index <= 21; index ++) {
diff --git a/EKF/ekf.cpp b/EKF/ekf.cpp
index 52647624c1..5fd2f28303 100644
--- a/EKF/ekf.cpp
+++ b/EKF/ekf.cpp
@@ -266,7 +266,6 @@ void Ekf::predictState()
 	// save the previous value of velocity so we can use trapzoidal integration
 	const Vector3f vel_last = _state.vel;
 
-	// update transformation matrix from body to world frame
 	_R_to_earth = Dcmf(_state.quat_nominal);
 
 	// Calculate an earth frame delta velocity
diff --git a/EKF/ekf_helper.cpp b/EKF/ekf_helper.cpp
index 513469d169..d8c485fb9d 100644
--- a/EKF/ekf_helper.cpp
+++ b/EKF/ekf_helper.cpp
@@ -1684,7 +1684,6 @@ void Ekf::resetExtVisRotMat()
 		_ev_rot_vec_filt.zero();
 	}
 
-	// reset the rotation matrix
 	_ev_rot_mat = Dcmf(q_error); // rotation from EV reference to EKF reference
 }
 
diff --git a/EKF/estimator_interface.cpp b/EKF/estimator_interface.cpp
index 692817a0e7..01f6acc9a3 100644
--- a/EKF/estimator_interface.cpp
+++ b/EKF/estimator_interface.cpp
@@ -397,10 +397,8 @@ void EstimatorInterface::setOpticalFlowData(uint64_t time_usec, flow_message *fl
 			// calculate the system time-stamp for the trailing edge of the flow data integration period
 			optflow_sample_new.time_us = time_usec - _params.flow_delay_ms * 1000;
 
-			// copy the quality metric returned by the PX4Flow sensor
 			optflow_sample_new.quality = flow->quality;
 
-			// copy the optical and gyro measured delta angles
 			// NOTE: the EKF uses the reverse sign convention to the flow sensor. EKF assumes positive LOS rate
 			// is produced by a RH rotation of the image about the sensor axis.
 			optflow_sample_new.gyroXYZ = - flow->gyrodata;
@@ -438,7 +436,6 @@ void EstimatorInterface::setExtVisionData(uint64_t time_usec, ext_vision_message
 		// calculate the system time-stamp for the mid point of the integration period
 		ev_sample_new.time_us = time_usec - _params.ev_delay_ms * 1000;
 
-		// copy required data
 		ev_sample_new.angErr = evdata->angErr;
 		ev_sample_new.posErr = evdata->posErr;
 		ev_sample_new.velErr = evdata->velErr;
@@ -447,7 +444,6 @@ void EstimatorInterface::setExtVisionData(uint64_t time_usec, ext_vision_message
 		ev_sample_new.pos = evdata->pos;
 		ev_sample_new.vel = evdata->vel;
 
-		// record time for comparison next measurement
 		_time_last_ext_vision = time_usec;
 
 		_ext_vision_buffer.push(ev_sample_new);
diff --git a/EKF/gps_yaw_fusion.cpp b/EKF/gps_yaw_fusion.cpp
index 17ec1e02de..c0f429fdc7 100644
--- a/EKF/gps_yaw_fusion.cpp
+++ b/EKF/gps_yaw_fusion.cpp
@@ -325,7 +325,6 @@ bool Ekf::resetGpsAntYaw()
 			euler_init(2) += yaw_delta;
 			euler_init(2) = wrap_pi(euler_init(2));
 
-			// update the quaternions
 			quat_after_reset = Quatf(euler_init);
 
 		} else {