https://itmanual.net/%ec%95%84%ec%9d%b4%ed%8f%b0-%ec%82%ac%ec%a7%84-%ec%9c%84%ec%b9%98-%eb%81%84%ea%b8%b0-gps%ec%a0%80%ec%9e%a5-%eb%b9%84%ed%99%9c%ec%84%b1%ed%99%94/