说明：  The actual version requires the following MATLAB toolboxes: - Mapping toolbox (for elevation()) - Image Processing Toolbox (for imshow()) A providing of toolbox independent functions would be greatly acknowledged. You may tweak the sourcecode to adjust the following information: - Receiver Position - Receiver Time offset to GMT - Path of ephemerides file - Path for satellite track recordings Ephemerides are taken from http://www.celestrak.com/NORAD/elements/galileo.txt and should be updated from time to time The satellite position calculation (calc_satposition_ecef.m) is based on a program from the Institute of Systems Optimization (ITE) at the University of Karlsruhe, Germany (http://www.ite.uni-karlsruhe.de/).