https://blog.gongquiz.com/2021/07/02/%ef%b8%8f-gps-%ec%9c%84%ec%b9%98%ec%b6%94%ec%a0%81-%ec%96%b4%ed%94%8c-%ec%97%86%ec%9d%b4-%ec%83%81%eb%8c%80%eb%b0%a9-%ed%95%b8%eb%93%9c%ed%8f%b0-%ec%9c%84%ec%b9%98%ec%b6%94%ec%a0%81-%ed%95%98/