Google maps. How update market current position without reload map?

Ionic Framework ionic-v3
#1

Hi, i have array with markets, and my current position too, but every 3 or 4 seconds reload all map, how i can reload only my market position??? Thanks its my code=>

loadMap() {
this.geolocation.watchPosition().subscribe((position) => {
this.lng = position.coords.longitude;
this.lat = position.coords.latitude;

  console.log('loadmapa');
  console.log('this.lat' + 'this.lng');
  console.log(this.lat + '' + this.lng);
  // create a new map by passing HTMLElement
  let mapEle: HTMLElement = document.getElementById('map');
  // create LatLng object
  let myLatLng   = { lat: this.lat, lng: this.lng };
  this.myposition = { latitude: this.lat, longitude: this.lng, name: '.', icon: 'img/car-placeholderb.png' };
  //alert(JSON.stringify(myLatLng));

  this.map = new google.maps.Map(mapEle, {
    center: myLatLng,
    zoom: 12
  });

  this.http.get('assets/markers.json')
    .map((res) => res.json())
    .subscribe(data => {
   
      data.push(this.myposition);
      console.log('all data');
      console.log(data);

      for (let i = 0; i < data.length; i++) {

        google.maps.event.addListenerOnce(this.map, 'idle', () => {
          let marker = new google.maps.Marker({
            position: { lat: data[i].latitude, lng: data[i].longitude },
            map: this.map,
            icon: data[i].icon,
            label: data[i].name
          });
          mapEle.classList.add('show-map');
        });

      }

    });

}, (err) => {
  console.log(err);
});

}

#2