MapXtreme+Asp.net 动态轨迹（请求大神指点）

功能简介：在MapXtreme+Asp.net的环境下实现轨迹回放功能，经过两天的努力基本实现此功能。但还有部分问题需要解决，求大神们指点迷津，问题会在结尾处提出。

客户端前台页面

<asp:ScriptManager ID="ScriptManager1" runat="server" />

        <%--该js方法写在scriptmanager之后，防止出现Sys未定义错误--%>

        <script type="text/javascript">

        //获取pagerequestmanager实例后添加事件

        //在因同步回发或因异步回发而刷新页面上所有内容后触发

        Sys.WebForms.PageRequestManager.getInstance().add_pageLoaded(TrackPlayBack);

        //轨迹回放函数

        function TrackPlayBack()

        {

            var myInput1 = document.getElementById("input1");//用来存放X坐标的控件

            var myInput2 = document.getElementById("input2");

            if(myInput1 != null && myInput2 != null)

            {

                var pointX = myInput1.value.toString();//地图上X坐标点

                var pointY = myInput2.value.toString();//地图上Y坐标点

                if(pointX != "" && pointY != "")

                {

                    var mapImage = document.getElementById("MapControl1_Image");//获取地图控件

                    if(mapImage != null)

                    {

                        //传递URL数据

                        var url = "MapController.ashx?Command=TrackPlayBack&PointX=" + pointX +"&PointY=" + pointY

                        + "&MapAlias=" + mapImage.mapAlias + "&Width=" + mapImage.width +"&Height=" + mapImage.height

                        + "&ExportFormat=" + mapImage.exportFormat + "&Ran=" + Math.random();

                        //使用Ajax局部刷新更新地图

                        var xmlHttp = CreateXMLHttp();

                        xmlHttp.open("GET",url,false);

                        xmlHttp.send();

                        mapImage.src = url;

                    }

                }

            }

         }

        </script>

        <cc1:MapControl ID="MapControl1" runat="server" Width="" Height="" ExportFormat="Jpeg" MapAlias="Map1"/>

        <asp:UpdatePanel ID="UpdatePanel1" runat="server">

            <ContentTemplate>

                <input id="input1" runat="server" type="text" style="width:200;" />

                <input id="input2" runat="server" type="text" style="width:200;" />

                <input id="input3" runat="server" type="text" style="width:200;" />

            </ContentTemplate>

            <Triggers>

                <asp:AsyncPostBackTrigger ControlID="Timer1" />

            </Triggers>

        </asp:UpdatePanel>

<asp:Timer ID="Timer1" runat="server" Enabled="true" Interval=""

            ontick="Timer1_Tick" />

客户端中调用的自定义服务器MapBaseCommand类

/// <summary>

    /// 轨迹回放

    /// </summary>

    [Serializable]

    public class TrackPlayBack : MapBaseCommand

    {

        private Catalog myCatalog = MapInfo.Engine.Session.Current.Catalog;

        /// <summary>

        /// 动画回放图层别名

        /// </summary>

        private string animationName = "动画回放";

        /// <summary>

        /// 动画回放图元Style

        /// </summary>

        private MapInfo.Styles.BitmapPointStyle trackBmpPointStyle = new MapInfo.Styles.BitmapPointStyle("TRUC1-32.BMP", MapInfo.Styles.BitmapStyles.NativeSize, System.Drawing.Color.Blue, );

        public TrackPlayBack(string _animationName, MapInfo.Styles.BitmapPointStyle  _trackBmpPointStyle)

        {

            Name = "TrackPlayBack";

            animationName = _animationName;

            trackBmpPointStyle = _trackBmpPointStyle;

        }

        public override void Process()

        {

            //获取分站坐标

            double pointX, pointY;

            double.TryParse(HttpContext.Current.Request["PointX"].ToString(), out pointX);

            double.TryParse(HttpContext.Current.Request["PointY"].ToString(), out pointY);

            //获取实现与执行各种操作的MapContorlModel实例

            MapControlModel myCtrlModel = MapControlModel.GetModelFromSession();

            try

            {

                //获取地图实例

                Map myMap = myCtrlModel.GetMapObj(MapAlias);

                if(myMap != null)

                {

                    //清空地图轨迹回放图元

                    MapInfo.Data.Table myTable = myCatalog.GetTable(animationName);

                    if(myTable != null)

                    {

                        #region 清空图元

                        SearchInfo mySearchInfo = MapInfo.Data.SearchInfoFactory.SearchWhere("");

                        IResultSetFeatureCollection myIRetFeaColl = myCatalog.Search(myTable, mySearchInfo);

                        if(myIRetFeaColl != null)

                        {

                            foreach(Feature myObj in myIRetFeaColl)

                            {

                                myTable.DeleteFeature(myObj);

                            }

                        }

                        #endregion

                        #region 添加图元

                        MapInfo.Geometry.Point myPoint = new MapInfo.Geometry.Point(myMap.GetDisplayCoordSys(), new MapInfo.Geometry.DPoint(pointX, pointY));

                        Feature myFeature = new Feature(myTable.TableInfo.Columns);

                        myFeature.Geometry = myPoint;

                        myFeature.Style = trackBmpPointStyle;

                        myTable.InsertFeature(myFeature);

                        #endregion

                    }

                }

            }

            finally

            {

                System.IO.MemoryStream ms = myCtrlModel.GetMap(MapAlias, MapWidth, MapHeight, ExportFormat);

                StreamImageToClient(ms);

            }

        }

    }

后台代码

//此处使用Timer模拟生成的点作为动态轨迹的坐标点

protected void Timer1_Tick(object sender, EventArgs e)

    {

        double pointX =  + myRandom.NextDouble() * ;

        double pointY = pointX;

        this.input1.Value = pointX.ToString();

        this.input2.Value = pointY.ToString();

    }

问题：该功能采用异步更新图元位置，并设置Timer的Interval为50ms（甚至更小），使用IE浏览器坐标点更新速度1-3次/s,使用搜狗浏览器坐标点的更新速度则更慢。怎么样才能使更新速度更快，问题出在何处？是MapXtreme异步更新本身的问题吗？