Cesium high resolution

var viewer = new Cesium.Viewer('cesiumContainer', {
    shadows : true
});
// When true, the sphere will have an elevation occlusion effect (there will also be an elevation occlusion effect when there is no terrain) 
viewer.scene.globe.depthTestAgainstTerrain = true ;

var viewModel = {
    height: 0
};

Cesium.knockout.track(viewModel);
// Get the toolbar in the upper left corner 
var toolbar = document.getElementById('toolbar' );
Cesium.knockout.applyBindings(viewModel, toolbar);
// Add 3D Tiles, the url is the path 
var tileset = new Cesium.Cesium3DTileset({ url: Cesium.IonResource.fromAssetId(3883 ) });
 // The root of the tileset is ready 
tileset.readyPromise.then( function (tileset) {
     // Add tileset to the scene 
    viewer.scene.primitives.add(tileset);
     // zoomTo (target, offset) target and offset 
    viewer.zoomTo(tileset, new Cesium.HeadingPitchRange(0.0, -0.5, tileset.boundingSphere.radius * 2.0 ));
}).otherwise( function (error) {
     // If the loading is not successful, it will prompt an error 
    console.log(error);
});

Cesium.knockout.getObservable(viewModel, 'height').subscribe(function(height) {
    height = Number(height);
    if (isNaN(height)) {
        return;
        }
//地理位置
    var cartographic = Cesium.Cartographic.fromCartesian(tileset.boundingSphere.center);
    var surface = Cesium.Cartesian3.fromRadians(cartographic.longitude, cartographic.latitude, 0.0);
    var offset = Cesium.Cartesian3.fromRadians(cartographic.longitude, cartographic.latitude, height);
    var translation = Cesium.Cartesian3.subtract(offset, surface, new Cesium.Cartesian3());
    tileset.modelMatrix = Cesium.Matrix4.fromTranslation(translation);
});