diff --git a/EKF/control.cpp b/EKF/control.cpp
index e18713a647..9d96728eda 100644
--- a/EKF/control.cpp
+++ b/EKF/control.cpp
@@ -513,7 +513,7 @@ void Ekf::controlGpsFusion()
 
 		// GPS yaw aiding selection logic
 		if ((_params.fusion_mode & MASK_USE_GPSYAW)
-				&& isfinite(_gps_sample_delayed.yaw)
+				&& ISFINITE(_gps_sample_delayed.yaw)
 				&& _control_status.flags.tilt_align
 				&& (!_control_status.flags.gps_yaw || !_control_status.flags.yaw_align)
 				&& (_time_last_imu - _time_last_gps < 2 * GPS_MAX_INTERVAL)) {
diff --git a/EKF/gps_yaw_fusion.cpp b/EKF/gps_yaw_fusion.cpp
index 61f72db433..da60b57538 100644
--- a/EKF/gps_yaw_fusion.cpp
+++ b/EKF/gps_yaw_fusion.cpp
@@ -59,7 +59,7 @@ void Ekf::fuseGpsAntYaw()
 	float measured_hdg;
 
 	// check if data has been set to NAN indicating no measurement
-	if (isfinite(_gps_sample_delayed.yaw)) {
+	if (ISFINITE(_gps_sample_delayed.yaw)) {
 		// calculate the observed yaw angle of antenna array, converting a from body to antenna yaw measurement
 		measured_hdg = _gps_sample_delayed.yaw + _gps_yaw_offset;
 
@@ -293,7 +293,7 @@ void Ekf::fuseGpsAntYaw()
 bool Ekf::resetGpsAntYaw()
 {
 	// check if data has been set to NAN indicating no measurement
-	if (isfinite(_gps_sample_delayed.yaw)) {
+	if (ISFINITE(_gps_sample_delayed.yaw)) {
 
 		// define the predicted antenna array vector and rotate into earth frame
 		Vector3f ant_vec_bf = {cosf(_gps_yaw_offset), sinf(_gps_yaw_offset), 0.0f};