Vlbi, Data Software Approach To Study

There are two kinds of Very Long Baseline Interferometry (VLBI) correlators, hardware correlator and software correlator. Although at present, most VLBI correlators are hardware ones, the rapid progress of the general computers shows that the software correlator maybe popular in the future. In the first two chapters, the contemporary situation of the VLBI correlator, and the mathematic model of VLBI correlation are presented. In chapter 3, the data simulation algorithms are studied firstly, and then a FX type correlation program is written on the MATLAB platform. Besides, some relevant problems, such as the power spectrum estimation method, window selection, the integer and fractional sample time correction, and the fringe stopping methods are also discussed The algorithm optimization of the mathematic model and parameters are discussed in chapter 4 and 5 . The self-developed software correlator are used to process the signals of an extragalactic radio source and satellites. The situation of 3-station delay closure test based on the three Chinese VLBI network stations was successfully made by the software. When the integral time is 0. 524288s,the final delay closure error is only 9. 0072±32.983ns. Finally, in chapter 6, the feasibility of improving the software correlation speed and the potential application of the software correlator are also discussed.