diff --git a/libraries/AP_Compass/Compass.h b/libraries/AP_Compass/Compass.h
index f02f78c833..815a598faa 100644
--- a/libraries/AP_Compass/Compass.h
+++ b/libraries/AP_Compass/Compass.h
@@ -87,7 +87,7 @@ public:
 	/// @param  latitude             GPS Latitude.
 	/// @param  longitude            GPS Longitude.
 	///
-	void set_initial_location(long latitude, long longitude);
+	void set_initial_location(int32_t latitude, int32_t longitude);
 
 	/// Program new offset values.
 	///