// Update is called once per frame
    void Update()
    {
        systemMilSec = systemMilSec + Time.deltaTime;
        if (UPDATE_TIME_GAP < systemMilSec)
        {
            systemMilSec = 0;
            gpsLastLoc   = gpsManager.GetLastLocationData();
            AppendLogger("lat: " + gpsLastLoc[0] + " long: " + gpsLastLoc[1] + " state: " + gpsLastLoc[2]);
            SubwayDataDetailModel subwayDataDetailModel = subwayManager.FindNearestSubwayStation(gpsLastLoc[0], gpsLastLoc[1]);
            if (subwayDataDetailModel == null)
            {
                AppendLogger("cannot find nearest station");
                SetNearestSubwayLocation(null);
            }
            else
            {
                AppendLogger("station name: " + subwayDataDetailModel.station_nm);
                Debug.Log("nearest station: " + subwayDataDetailModel.station_nm);
                SaveNearestStation(subwayDataDetailModel);

                SetNearestSubwayLocation(subwayDataDetailModel);
            }
        }
    }