diff --git a/libs/mavlink/include/mavlink/v1.0/mavlink_conversions.h b/libs/mavlink/include/mavlink/v1.0/mavlink_conversions.h
index 51afac87c3cce1d0b2933e4f4c90b763382f86b2..45528d61db32e7109faf9d4bf00223329a6a93ea 100644
--- a/libs/mavlink/include/mavlink/v1.0/mavlink_conversions.h
+++ b/libs/mavlink/include/mavlink/v1.0/mavlink_conversions.h
@@ -1,16 +1,10 @@
 #ifndef  _MAVLINK_CONVERSIONS_H_
 #define  _MAVLINK_CONVERSIONS_H_
 
-/* enable math defines on Windows */
-#ifdef _MSC_VER
-#ifndef _USE_MATH_DEFINES
-#define _USE_MATH_DEFINES
-#endif
-#endif
 #include <math.h>
 
 #ifndef M_PI_2
-    #define M_PI_2 ((float)asin(1))
+    #define M_PI_2 ((float)asin(1.0f))
 #endif
 
 /**