diff --git a/PlaneGcsSdk_Shared/CommunicationManagement/CommModuleGenerateMavLink.cs b/PlaneGcsSdk_Shared/CommunicationManagement/CommModuleGenerateMavLink.cs
index 30ea88f..3833b94 100644
--- a/PlaneGcsSdk_Shared/CommunicationManagement/CommModuleGenerateMavLink.cs
+++ b/PlaneGcsSdk_Shared/CommunicationManagement/CommModuleGenerateMavLink.cs
@@ -198,6 +198,23 @@ namespace Plane.CommunicationManagement
             return packetNum;
         }
 
+
+        /// <summary>
+        /// 读取参数
+        /// </summary>
+        /// <param name="paramname"></param>
+        /// <param name="copters"></param>
+        /// <returns></returns>
+        public async Task ReadParamAsnyc(string paramname, IEnumerable<ICopter> copters = null)
+        {
+            short copterId = 0;
+            byte[] batchPacket = null;
+            GetCopterIds(copters, out copterId, out batchPacket);
+
+            byte[] packet = GetParam2Async(paramname);
+            await WriteCommPacketAsync(copterId, MavComm.COMM_DOWNLOAD_COMM, packet, batchPacket).ConfigureAwait(false);
+        }
+
         /// <summary>
         /// 起飞测试
         /// </summary>
@@ -235,6 +252,9 @@ namespace Plane.CommunicationManagement
             await WriteCommPacketAsync((short)copterId, MavComm.COMM_DOWNLOAD_COMM, packet, batchPacket).ConfigureAwait(false);
         }
 
+
+       
+
         /// <summary>
         /// 获取版本
         /// </summary>
@@ -338,13 +358,48 @@ namespace Plane.CommunicationManagement
             await WriteCommPacketAsync(copterId, MavComm.COMM_DOWNLOAD_COMM, packet, batchPacket).ConfigureAwait(false);
         }
 
+        /// <summary>
+        /// 校准加速计
+        /// </summary>
+        /// <param name="copterId"></param>
+        /// <returns></returns>
+        public async Task DoStartPreflightCompassAsync(short copterId)
+        {
+            byte[] packet = DoCommandAsync(MAVLink.MAV_CMD.PREFLIGHT_CALIBRATION, 0, 0, 0, 0, 1, 0, 0);
+            await WriteCommPacketAsync(copterId, MavComm.COMM_DOWNLOAD_COMM, packet).ConfigureAwait(false);
+        }
 
+        /// <summary>
+        /// 校准加速计下一步
+        /// </summary>
+        /// <param name="copterId"></param>
+        /// <returns></returns>
+        public async Task DoNextPreflightCompassAsync(short copterId)
+        {
+            MAVLink.mavlink_command_ack_t req = new MAVLink.mavlink_command_ack_t();
+            req.command = 1;
+            req.result = 1;
+
+            byte[] packet = GeneratePacket(MAVLink.MAVLINK_MSG_ID_COMMAND_ACK, req);
+            await WriteCommPacketAsync(copterId, MavComm.COMM_DOWNLOAD_COMM, packet).ConfigureAwait(false);
+        }
+
+        /// <summary>
+        /// 校准指南针
+        /// </summary>
+        /// <param name="copterId"></param>
+        /// <returns></returns>
         public async Task DoCalibrationCompassAsync(short copterId)
         {
             byte[] packet = DoCommandAsync(MAVLink.MAV_CMD.DO_START_MAG_CAL, 0, 1, 1, 0, 0, 0, 0);
             await WriteCommPacketAsync(copterId, MavComm.COMM_DOWNLOAD_COMM, packet).ConfigureAwait(false);
         }
 
+        /// <summary>
+        /// 放弃校准指南针
+        /// </summary>
+        /// <param name="copterId"></param>
+        /// <returns></returns>
         public async Task DoCancelCalibrationCompassAsync(short copterId)
         {
             byte[] packet = DoCommandAsync(MAVLink.MAV_CMD.DO_CANCEL_MAG_CAL, 0, 0, 1, 0, 0, 0, 0);
@@ -557,6 +612,22 @@ namespace Plane.CommunicationManagement
             return GeneratePacket((byte)MAVLink.MAVLINK_MSG_ID_PARAM_SET, req);
         }
 
+        private byte[] GetParam2Async(string paramname)
+        {
+            var paramId = Encoding.ASCII.GetBytes(paramname);
+            Array.Resize(ref paramId, 16);
+
+            var req = new MAVLink.mavlink_param_request_read_t
+            {
+                param_index = -1,
+                target_system = 1,
+                target_component = 1,
+                param_id = paramId
+            };
+
+            return GeneratePacket(MAVLink.MAVLINK_MSG_ID_PARAM_REQUEST_READ, req);
+        }
+
         private byte[] DoLEDCommandAsync()
         {
             MAVLink.mavlink_msg_id_led_control led = new MAVLink.mavlink_msg_id_led_control();
diff --git a/PlaneGcsSdk_Shared/Copters/CopterImplSharedPart.cs b/PlaneGcsSdk_Shared/Copters/CopterImplSharedPart.cs
index 7d5cab4..0c88891 100644
--- a/PlaneGcsSdk_Shared/Copters/CopterImplSharedPart.cs
+++ b/PlaneGcsSdk_Shared/Copters/CopterImplSharedPart.cs
@@ -614,10 +614,20 @@ namespace Plane.Copters
             protected set { Set(nameof(SatCount), ref _SatCount, value); }
         }
 
+        public float RetainInt
+        {
+            get { return BitConverter.ToSingle(Retain,0); }
+        }
+
+
         public byte[] Retain
         {
             get { return _Retain; }
-            protected set { Set(nameof(Retain), ref _Retain, value); }
+            protected set
+            {
+                Set(nameof(Retain), ref _Retain, value);
+                RaisePropertyChanged(nameof(RetainInt));
+            }
         }
 
         public CopterState State
diff --git a/PlaneGcsSdk_Shared/Copters/EHCopter.InternalCopterEventHandlers.cs b/PlaneGcsSdk_Shared/Copters/EHCopter.InternalCopterEventHandlers.cs
index 5ba365e..c07b5cb 100644
--- a/PlaneGcsSdk_Shared/Copters/EHCopter.InternalCopterEventHandlers.cs
+++ b/PlaneGcsSdk_Shared/Copters/EHCopter.InternalCopterEventHandlers.cs
@@ -31,7 +31,7 @@ namespace Plane.Copters
                         GpsHdop = _internalCopter.gpshdop;
                         Altitude = _internalCopter.gpsalt;
                         Retain = BitConverter.GetBytes(_internalCopter.retain);
-                        Windows.Messages.Message.Show("_internalCopter.retain = " + _internalCopter.retain.ToString());
+                        
                         Voltage = _internalCopter.battery_voltage;
                         CommModuleMode = (FlightMode)_internalCopter.commModuleMode;
                         CommModuleVersion = _internalCopter.commModuleVersion;
diff --git a/PlaneGcsSdk_Shared/Copters/PlaneCopter.cs b/PlaneGcsSdk_Shared/Copters/PlaneCopter.cs
index 1d275de..ea9390b 100644
--- a/PlaneGcsSdk_Shared/Copters/PlaneCopter.cs
+++ b/PlaneGcsSdk_Shared/Copters/PlaneCopter.cs
@@ -58,7 +58,7 @@ namespace Plane.Copters
         public byte gpsstatus { get; set; }
         public float gpshdop { get; set; }
         public byte satcount { get; set; }
-        public int retain { get; set; }
+        public float retain { get; set; }
         public float groundspeed { get; set; }
         public float groundcourse { get; set; }
         public double lat { get; set; }
diff --git a/PlaneGcsSdk_Shared/Protocols/MavCommTypes.cs b/PlaneGcsSdk_Shared/Protocols/MavCommTypes.cs
index 92a91fc..1006063 100644
--- a/PlaneGcsSdk_Shared/Protocols/MavCommTypes.cs
+++ b/PlaneGcsSdk_Shared/Protocols/MavCommTypes.cs
@@ -144,7 +144,7 @@ namespace Plane.Protocols
             public Int32 control_mode;
             public UInt32 lat;
             public UInt32 lng;
-            public Int32 retain;
+            public float retain;
             public Int32 alt;
 
             public Int16 gps_status;