def get_home(self):
        '''get home location'''
        if 'HOME_POSITION' in self.master.messages:
            h = self.master.messages['HOME_POSITION']
            return mavutil.mavlink.MAVLink_mission_item_message(self.target_system,
                                                                self.target_component,
                                                                0,
                                                                0,
                                                                mavutil.mavlink.MAV_CMD_NAV_WAYPOINT,
                                                                0, 0, 0, 0, 0, 0,
                                                                h.latitude*1.0e-7, h.longitude*1.0e-7, h.altitude*1.0e-3)
        if self.wploader.count() > 0:
            return self.wploader.wp(0)
        return None
get home location