diff --git a/libraries/AP_Math/definitions.h b/libraries/AP_Math/definitions.h
index 446c92fd78b..3194dc607d7 100644
--- a/libraries/AP_Math/definitions.h
+++ b/libraries/AP_Math/definitions.h
@@ -7,7 +7,7 @@
 #ifdef M_PI
 # undef M_PI
 #endif
-#define M_PI      (3.141592653589793)
+#define M_PI      (3.141592653589793238462643383279502884)
 
 #ifdef M_PI_2
 # undef M_PI_2