diff --git a/src/Geo/QGCGeo.cc b/src/Geo/QGCGeo.cc
index 9621b7572ee886206935eae66ab0b7c7012e2b22..cbe1d14cc14cdee7d28c0f752ae8e0f9d10d2d9b 100644
--- a/src/Geo/QGCGeo.cc
+++ b/src/Geo/QGCGeo.cc
@@ -46,7 +46,7 @@ void convertGeoToNed(QGeoCoordinate coord, QGeoCoordinate origin, double* x, dou
     double ref_cos_lat = cos(ref_lat_rad);
 
     double c = acos(ref_sin_lat * sin_lat + ref_cos_lat * cos_lat * cos_d_lon);
-    double k = (abs(c) < epsilon) ? 1.0 : (c / sin(c));
+    double k = (fabs(c) < epsilon) ? 1.0 : (c / sin(c));
 
     *x = k * (ref_cos_lat * sin_lat - ref_sin_lat * cos_lat * cos_d_lon) * CONSTANTS_RADIUS_OF_EARTH;
     *y = k * cos_lat * sin(lon_rad - ref_lon_rad) * CONSTANTS_RADIUS_OF_EARTH;
@@ -70,7 +70,7 @@ void convertNedToGeo(double x, double y, double z, QGeoCoordinate origin, QGeoCo
     double lat_rad;
     double lon_rad;
 
-    if (abs(c) > epsilon) {
+    if (fabs(c) > epsilon) {
         lat_rad = asin(cos_c * ref_sin_lat + (x_rad * sin_c * ref_cos_lat) / c);
         lon_rad = (ref_lon_rad + atan2(y_rad * sin_c, c * ref_cos_lat * cos_c - x_rad * ref_sin_lat * sin_c));