diff --git a/libraries/GCS_MAVLink/include/mavlink/v1.0/ardupilotmega/ardupilotmega.h b/libraries/GCS_MAVLink/include/mavlink/v1.0/ardupilotmega/ardupilotmega.h
index d269150661..ac7accc1eb 100644
--- a/libraries/GCS_MAVLink/include/mavlink/v1.0/ardupilotmega/ardupilotmega.h
+++ b/libraries/GCS_MAVLink/include/mavlink/v1.0/ardupilotmega/ardupilotmega.h
@@ -47,6 +47,7 @@ typedef enum MAV_CMD
 	MAV_CMD_NAV_LAND=21, /* Land at location |Empty| Empty| Empty| Desired yaw angle.| Latitude| Longitude| Altitude|  */
 	MAV_CMD_NAV_TAKEOFF=22, /* Takeoff from ground / hand |Minimum pitch (if airspeed sensor present), desired pitch without sensor| Empty| Empty| Yaw angle (if magnetometer present), ignored without magnetometer| Latitude| Longitude| Altitude|  */
 	MAV_CMD_NAV_CONTINUE_AND_CHANGE_ALT=30, /* Continue on the current course and climb/descend to specified altitude.  When the altitude is reached continue to the next command (i.e., don't proceed to the next command until the desired altitude is reached. |Empty| Empty| Empty| Empty| Empty| Empty| Desired altitude in meters|  */
+	MAV_CMD_NAV_LOITER_TO_ALT=31, /* Begin loiter at the specified Latitude and Longitude.  If Lat=Lon=0, then loiter at the current position.  Don't consider the navigation command complete (don't leave loiter) until the altitude has been reached.  Additionally, if the Heading Required parameter is non-zero the  aircraft will not leave the loiter until heading toward the next waypoint.  |Heading Required (0 = False)| Radius in meters. If positive loiter clockwise, negative counter-clockwise, 0 means no change to standard loiter.| Empty| Empty| Latitude| Longitude| Altitude|  */
 	MAV_CMD_NAV_ROI=80, /* Sets the region of interest (ROI) for a sensor set or the vehicle itself. This can then be used by the vehicles control system to control the vehicle attitude and the attitude of various sensors such as cameras. |Region of intereset mode. (see MAV_ROI enum)| MISSION index/ target ID. (see MAV_ROI enum)| ROI index (allows a vehicle to manage multiple ROI's)| Empty| x the location of the fixed ROI (see MAV_FRAME)| y| z|  */
 	MAV_CMD_NAV_PATHPLANNING=81, /* Control autonomous path planning on the MAV. |0: Disable local obstacle avoidance / local path planning (without resetting map), 1: Enable local path planning, 2: Enable and reset local path planning| 0: Disable full path planning (without resetting map), 1: Enable, 2: Enable and reset map/occupancy grid, 3: Enable and reset planned route, but not occupancy grid| Empty| Yaw angle at goal, in compass degrees, [0..360]| Latitude/X of goal| Longitude/Y of goal| Altitude/Z of goal|  */
 	MAV_CMD_NAV_SPLINE_WAYPOINT=82, /* Navigate to MISSION using a spline path. |Hold time in decimal seconds. (ignored by fixed wing, time to stay at MISSION for rotary wing)| Empty| Empty| Empty| Latitude/X of goal| Longitude/Y of goal| Altitude/Z of goal|  */
diff --git a/libraries/GCS_MAVLink/include/mavlink/v1.0/ardupilotmega/version.h b/libraries/GCS_MAVLink/include/mavlink/v1.0/ardupilotmega/version.h
index 3ed9ffbdc7..81be4fdbce 100644
--- a/libraries/GCS_MAVLink/include/mavlink/v1.0/ardupilotmega/version.h
+++ b/libraries/GCS_MAVLink/include/mavlink/v1.0/ardupilotmega/version.h
@@ -5,7 +5,7 @@
 #ifndef MAVLINK_VERSION_H
 #define MAVLINK_VERSION_H
 
-#define MAVLINK_BUILD_DATE "Tue Apr 21 06:16:12 2015"
+#define MAVLINK_BUILD_DATE "Fri Apr 24 07:12:12 2015"
 #define MAVLINK_WIRE_PROTOCOL_VERSION "1.0"
 #define MAVLINK_MAX_DIALECT_PAYLOAD_SIZE 255
  
diff --git a/libraries/GCS_MAVLink/include/mavlink/v1.0/common/version.h b/libraries/GCS_MAVLink/include/mavlink/v1.0/common/version.h
index 891eeeaad1..f7e5e19af2 100644
--- a/libraries/GCS_MAVLink/include/mavlink/v1.0/common/version.h
+++ b/libraries/GCS_MAVLink/include/mavlink/v1.0/common/version.h
@@ -5,7 +5,7 @@
 #ifndef MAVLINK_VERSION_H
 #define MAVLINK_VERSION_H
 
-#define MAVLINK_BUILD_DATE "Tue Apr 21 06:16:14 2015"
+#define MAVLINK_BUILD_DATE "Fri Apr 24 07:12:15 2015"
 #define MAVLINK_WIRE_PROTOCOL_VERSION "1.0"
 #define MAVLINK_MAX_DIALECT_PAYLOAD_SIZE 255
  
diff --git a/libraries/GCS_MAVLink/include/mavlink/v1.0/mavlink_types.h b/libraries/GCS_MAVLink/include/mavlink/v1.0/mavlink_types.h
index 2f28f7ae18..7fe6297fb1 100644
--- a/libraries/GCS_MAVLink/include/mavlink/v1.0/mavlink_types.h
+++ b/libraries/GCS_MAVLink/include/mavlink/v1.0/mavlink_types.h
@@ -80,8 +80,9 @@ typedef struct param_union {
  * and the bits pulled out using the shifts/masks.
 */
 MAVPACKED(
-typedef union {
-    struct __data{
+typedef struct param_union_extended {
+    union {
+    struct {
         uint8_t is_double:1;
         uint8_t mavlink_type:7;
         union {
@@ -97,6 +98,7 @@ typedef union {
         };
     };
     uint8_t data[8];
+    };
 }) mavlink_param_union_double_t;
 
 /**