Servie again restarts and timer is also get count from zero how to deal with that

Here is my code i am storing location of user after 30min but i think when i use mobile it's service is again get restarted and again 30min starts from zero so my storing location time is not perfect 30min please tell what should i have to do ? to achieve that.

public class AppService extends Service implements LocationListener {

        public void onCreate() {
            super.onCreate();
            System.out.println("Inside onCreate  Service class");
            context = this;
            dbObj = new MyDB(context, "MyDB", null, 1);
            dbObj.getWritableDatabase();

            final Handler handler = new Handler();
            timer = new Timer();
            TimerTask doAsynchronousTask = new TimerTask() {
                @Override
                public void run() {
                    handler.post(new Runnable() {
                        public void run() {
                            Log.e("run", "run");
                            System.out.println("Inside onCreate  run run");
                            RunServices();
                            // if (Utils.getNetworkStatus()) {
                            //
                            // } else {
                            saveDataToLocalDB();
                            // }
                        }
                    });
                }
            };
            timer.schedule(doAsynchronousTask, 1800000, 1800000);
            CheckLocatinData();
        }
}