var view = new ol.View({
        center: [0, 0],
        zoom: 4
      });

      var map = new ol.Map({
        layers: [
          new ol.layer.Tile({
            source: new ol.source.OSM()
          })
        ],
        target: 'map',
        controls: ol.control.defaults({
              attributionOptions: /** @type {olx.control.AttributionOptions} */ ({
                collapsible: false
              })
        }),
        view: view
      });



      var geolocation = new ol.Geolocation({
    projection: map.getView().getProjection(),
    tracking: true,
    trackingOptions: {
      enableHighAccuracy: true,
      maximumAge: 2000
    }
  });


  var iconStyle = new ol.style.Style({
  image: new ol.style.Circle({
          radius: 9,
          fill: new ol.style.Fill({
            color: '#9779CC'
          }),
          stroke: new ol.style.Stroke({
            color: '#fAf',
            width: 2
          })
        })
      });

// add an empty iconFeature to the source of the layer
  var iconFeature = new ol.Feature();
  var iconSource = new ol.source.Vector({
    features: [iconFeature]
  });
  var iconLayer = new ol.layer.Vector({
    source: iconSource,
    style : iconStyle
  });
  map.addLayer(iconLayer);

 geolocation.on('change', function() {
    var pos = geolocation.getPosition();
    var pos2="-5.73487946125,37.33522475130639";

    iconFeature.setGeometry(new ol.geom.Point(pos));
    view.setCenter(pos);
    //view.setZoom(18);

    // iconFeature.setGeometry(new ol.geom.Point(pos2));
  });