说明：  使用matlab编写的经纬高、东北天数据和地心坐标数据之间的转换函数文件，包含了东北天坐标系的定义说明文件以及相关的转换公式。 三个函数的调用文件名：ECEFtoENV，ECEFtoLBH，LBHtoECEF。使用说明见函数的说明。
(Prepared using matlab high latitude and longitude, northeast-day data and geocentric coordinate conversion functions between data file that contains the definition of the coordinate system Northeast day documentation and related conversion formulas. Three function calls filename: ECEFtoENV, ECEFtoLBH, LBHtoECEF. See the instructions for use function.)