ArduCopter: Changed implementation of configuration value for automatic declination. There is now a FORCE_AUTOMATIC_DECLINATION_UPDATE that when enabled will update the declination on every GPS 3D fix regardless of whether or not the user saved a value to the EEPROM. By default the declination will only be set by the automatic declination routine if the user has not saved a declination to the EEPROM.

ArduCopter/ArduCopter.pde

@@ -95,10 +95,7 @@ http://code.google.com/p/ardupilot-mega/downloads/list
 #include "Parameters.h"
 #include "GCS.h"
 
-#if AUTOMATIC_DECLINATION == ENABLED
-// this is in an #if to avoid the static data
 #include <AP_Declination.h> // ArduPilot Mega Declination Helper Library
-#endif
 
 ////////////////////////////////////////////////////////////////////////////////
 // Serial ports
@@ -1381,12 +1378,10 @@ static void update_GPS(void)
 				ground_start_count = 5;
 
 			}else{
-#if AUTOMATIC_DECLINATION == ENABLED
 				if(g.compass_enabled) {
 					// Set compass declination automatically
-					compass.set_initial_location(g_gps->latitude, g_gps->longitude, false);
+					compass.set_initial_location(g_gps->latitude, g_gps->longitude, (FORCE_AUTOMATIC_DECLINATION_UPDATE == ENABLED));
 				}
-#endif
 				// save home to eeprom (we must have a good fix to have reached this point)
 				init_home();
 				ground_start_count = 0;

ArduCopter/config.h

@@ -425,8 +425,8 @@
 # define GROUND_START_DELAY		3
 #endif
 
-#ifndef AUTOMATIC_DECLINATION
-	#define AUTOMATIC_DECLINATION DISABLED
+#ifndef FORCE_AUTOMATIC_DECLINATION_UPDATE
+	#define FORCE_AUTOMATIC_DECLINATION_UPDATE DISABLED
 #endif