diff --git a/libraries/AP_Common/AP_Common.h b/libraries/AP_Common/AP_Common.h
index 4577ed23b7..2b7c7436d4 100644
--- a/libraries/AP_Common/AP_Common.h
+++ b/libraries/AP_Common/AP_Common.h
@@ -65,9 +65,16 @@
 # undef PSTR 
 # define PSTR(s) (__extension__({static prog_char __c[] PROGMEM = (s); &__c[0];})) 
 #endif
-
 //@}
 
+///
+/// @name Macros
+/// @{
+#define ToRad(x) (x*0.01745329252)	// *pi/180
+#define ToDeg(x) (x*57.2957795131)	// *180/pi
+// @}
+
+
 ////////////////////////////////////////////////////////////////////////////////
 /// @name	Types
 ///