diff --git a/EKF/ekf.h b/EKF/ekf.h
index 728ea034a2..d9f8156201 100644
--- a/EKF/ekf.h
+++ b/EKF/ekf.h
@@ -641,7 +641,7 @@ private:
 	void fuse(float *K, float innovation);
 
 	// calculate the earth rotation vector from a given latitude
-	void calcEarthRateNED(Vector3f &omega, float lat_rad) const;
+	Vector3f calcEarthRateNED(float lat_rad) const;
 
 	// return true id the GPS quality is good enough to set an origin and start aiding
 	bool gps_is_good(const gps_message &gps);
diff --git a/EKF/ekf_helper.cpp b/EKF/ekf_helper.cpp
index 2382827e41..76c8708f24 100644
--- a/EKF/ekf_helper.cpp
+++ b/EKF/ekf_helper.cpp
@@ -791,11 +791,11 @@ void Ekf::constrainStates()
 }
 
 // calculate the earth rotation vector
-void Ekf::calcEarthRateNED(Vector3f &omega, float lat_rad) const
+Vector3f Ekf::calcEarthRateNED(float lat_rad) const
 {
-	omega(0) = CONSTANTS_EARTH_SPIN_RATE * cosf(lat_rad);
-	omega(1) = 0.0f;
-	omega(2) = -CONSTANTS_EARTH_SPIN_RATE * sinf(lat_rad);
+	return Vector3f{CONSTANTS_EARTH_SPIN_RATE * cosf(lat_rad),
+			0.0f,
+			-CONSTANTS_EARTH_SPIN_RATE * sinf(lat_rad)};
 }
 
 void Ekf::getGpsVelPosInnov(float hvel[2], float &vvel, float hpos[2],  float &vpos)
diff --git a/EKF/gps_checks.cpp b/EKF/gps_checks.cpp
index b72ec3b60a..af3b41833a 100644
--- a/EKF/gps_checks.cpp
+++ b/EKF/gps_checks.cpp
@@ -76,7 +76,7 @@ bool Ekf::collect_gps(const gps_message &gps)
 		// Take the current GPS height and subtract the filter height above origin to estimate the GPS height of the origin
 		_gps_alt_ref = 1e-3f * (float)gps.alt + _state.pos(2);
 		_NED_origin_initialised = true;
-		calcEarthRateNED(_earth_rate_NED, (float)_pos_ref.lat_rad);
+		_earth_rate_NED = calcEarthRateNED((float)_pos_ref.lat_rad);
 		_last_gps_origin_time_us = _time_last_imu;
 
 		// set the magnetic field data returned by the geo library using the current GPS position