diff --git a/APMrover2/APMrover2.pde b/APMrover2/APMrover2.pde
index e883a0eceb..8936d918da 100644
--- a/APMrover2/APMrover2.pde
+++ b/APMrover2/APMrover2.pde
@@ -679,6 +679,9 @@ static void medium_loop()
                 ahrs.set_compass(&compass);
                 // Calculate heading
                 compass.null_offsets();
+                if (g.log_bitmask & MASK_LOG_COMPASS) {
+                    Log_Write_Compass();
+                }
             } else {
                 ahrs.set_compass(NULL);
             }
diff --git a/APMrover2/Log.pde b/APMrover2/Log.pde
index ee1eb0f3d6..fabd7481c0 100644
--- a/APMrover2/Log.pde
+++ b/APMrover2/Log.pde
@@ -49,6 +49,7 @@ print_log_menu(void)
 		PLOG(CMD);
 		PLOG(CURRENT);
 		PLOG(SONAR);
+		PLOG(COMPASS);
 		#undef PLOG
 	}
 
@@ -137,6 +138,7 @@ select_logs(uint8_t argc, const Menu::arg *argv)
 		TARG(CMD);
 		TARG(CURRENT);
 		TARG(SONAR);
+		TARG(COMPASS);
 		#undef TARG
 	}
 
@@ -404,6 +406,40 @@ static void Log_Write_Current()
     DataFlash.WriteBlock(&pkt, sizeof(pkt));
 }
 
+struct PACKED log_Compass {
+    LOG_PACKET_HEADER;
+    int16_t mag_x;
+    int16_t mag_y;
+    int16_t mag_z;
+    int16_t offset_x;
+    int16_t offset_y;
+    int16_t offset_z;
+    int16_t motor_offset_x;
+    int16_t motor_offset_y;
+    int16_t motor_offset_z;
+};
+
+// Write a Compass packet. Total length : 15 bytes
+static void Log_Write_Compass()
+{
+    Vector3f mag_offsets = compass.get_offsets();
+    Vector3f mag_motor_offsets = compass.get_motor_offsets();
+    struct log_Compass pkt = {
+        LOG_PACKET_HEADER_INIT(LOG_COMPASS_MSG),
+        mag_x           : compass.mag_x,
+        mag_y           : compass.mag_y,
+        mag_z           : compass.mag_z,
+        offset_x        : (int16_t)mag_offsets.x,
+        offset_y        : (int16_t)mag_offsets.y,
+        offset_z        : (int16_t)mag_offsets.z,
+        motor_offset_x  : (int16_t)mag_motor_offsets.x,
+        motor_offset_y  : (int16_t)mag_motor_offsets.y,
+        motor_offset_z  : (int16_t)mag_motor_offsets.z
+    };
+    DataFlash.WriteBlock(&pkt, sizeof(pkt));
+}
+
+
 static const struct LogStructure log_structure[] PROGMEM = {
     LOG_COMMON_STRUCTURES,
     { LOG_ATTITUDE_MSG, sizeof(log_Attitude),       
diff --git a/APMrover2/config.h b/APMrover2/config.h
index facd7d4213..894ad92ee4 100644
--- a/APMrover2/config.h
+++ b/APMrover2/config.h
@@ -427,55 +427,16 @@
 # define LOGGING_ENABLED		ENABLED
 #endif
 
-#ifndef LOG_ATTITUDE_FAST
-# define LOG_ATTITUDE_FAST		DISABLED
-#endif
-#ifndef LOG_ATTITUDE_MED
-# define LOG_ATTITUDE_MED 		ENABLED
-#endif
-#ifndef LOG_GPS
-# define LOG_GPS 				ENABLED
-#endif
-#ifndef LOG_PM
-# define LOG_PM 				DISABLED
-#endif
-#ifndef LOG_CTUN
-# define LOG_CTUN				ENABLED
-#endif
-#ifndef LOG_NTUN
-# define LOG_NTUN				ENABLED
-#endif
-#ifndef LOG_MODE
-# define LOG_MODE				ENABLED
-#endif
-#ifndef LOG_IMU
-# define LOG_IMU				DISABLED
-#endif
-#ifndef LOG_CMD
-# define LOG_CMD				ENABLED
-#endif
-#ifndef LOG_CURRENT
-# define LOG_CURRENT			DISABLED
-#endif
-#ifndef LOG_SONAR
-# define LOG_SONAR			    ENABLED
-#endif
+#define DEFAULT_LOG_BITMASK     \
+    MASK_LOG_ATTITUDE_MED | \
+    MASK_LOG_GPS | \
+    MASK_LOG_PM | \
+    MASK_LOG_NTUN | \
+    MASK_LOG_MODE | \
+    MASK_LOG_CMD | \
+    MASK_LOG_SONAR | \
+    MASK_LOG_COMPASS
 
-// calculate the default log_bitmask
-#define LOGBIT(_s)	(LOG_##_s ? MASK_LOG_##_s : 0)
-
-#define DEFAULT_LOG_BITMASK \
-		LOGBIT(ATTITUDE_FAST)	| \
-		LOGBIT(ATTITUDE_MED)	| \
-		LOGBIT(GPS)				| \
-		LOGBIT(PM)				| \
-		LOGBIT(CTUN)			| \
-		LOGBIT(NTUN)			| \
-		LOGBIT(MODE)			| \
-		LOGBIT(IMU)				| \
-		LOGBIT(CMD)				| \
-		LOGBIT(SONAR)			| \
-		LOGBIT(CURRENT)
 
 
 //////////////////////////////////////////////////////////////////////////////
diff --git a/APMrover2/defines.h b/APMrover2/defines.h
index 0a3f98139e..a0c580a259 100644
--- a/APMrover2/defines.h
+++ b/APMrover2/defines.h
@@ -135,6 +135,7 @@ enum gcs_severity {
 #define LOG_SONAR_MSG 		    0x07
 #define LOG_ATTITUDE_MSG        0x08
 #define LOG_MODE_MSG            0x09
+#define LOG_COMPASS_MSG         0x0A
 
 #define TYPE_AIRSTART_MSG		0x00
 #define TYPE_GROUNDSTART_MSG	0x01
@@ -151,6 +152,7 @@ enum gcs_severity {
 #define MASK_LOG_CMD			(1<<8)
 #define MASK_LOG_CURRENT		(1<<9)
 #define MASK_LOG_SONAR   		(1<<10)
+#define MASK_LOG_COMPASS   		(1<<11)
 
 // Waypoint Modes
 // ----------------