RTKLIB provide the following general purpose Cfunctions callable from user AP (application program).User can use these function to develop user original positioning APs.(1) Matrix and vector functions 矩阵与向量函数(2) Time and string functions 时间和字符串函数(3) Coordinates transformation and geoid model坐标变换和大地水准面模型(4) Navigation processing 导航处理(5) Positioning models (troposphere, ionosphere, antenna PCV) 定位模型（对流层，电离层，天线PCV）(6) SBAS DGPS/DGNSS correction DGPS / SBAS DGNSS校正(7) Single point po
