The successor to the aforementioned ngCordova:
Ionic Native is a curated set of ES6/TypeScript wrappers for Cordova/PhoneGap plugins that make adding any native functionality you need to your Ionic, Cordova, or Web View mobile app easy.
import {Geolocation} from 'ionic-native';
Geolocation.getCurrentPosition().then(pos => {
console.log('lat: ' + pos.coords.latitude + ', lon: ' + pos.coords.longitude);
});
let watch = Geolocation.watchPosition();
watch.subscribe(pos => {
console.log('lat: ' + pos.coords.latitude + ', lon: ' + pos.coords.longitude);
});
// to stop watching
watch.unsubscribe();