BARREL 4C Ephemeris (EPHM) Geographic and Magnetic Coordinates, Level 2, 4 s Data

Geographic and Magnetic Coordinates: The ephemeris data products, which include the balloon epoch time, latitude, longitude, and altitude, are each returned from the payload once every 4s. Geographic coordinates are obtained from an onboard Global Positioning System, GPS, unit. Magnetic coordinates are derived by using the International Radiation Belt Environment Modeling, IRBEM, FORTRAN library.地理与地磁坐标：包含气球探测历元时间、纬度、经度及海拔高度的星历数据产品，均由有效载荷每4秒返回一次。其中地理坐标通过机载全球定位系统（Global Positioning System，GPS）设备获取，地磁坐标则借助国际辐射带环境建模（International Radiation Belt Environment Modeling，IRBEM）FORTRAN程序库推导得到。