The Haystack Observatory Postprocessing System (HOPS) is a software package
designed to analyze the data generated by DiFX VLBI correlators. It is written
in C for Linux computers, and emphasizes quality-control aspects of data
processing.  HOPS sits between the correlator and an image-processing and/or
geodetic-processing package, and performs basic fringe-fitting, data editing,
problem diagnosis, and correlator support functions. 


For more information, please see:  

  https://www.haystack.mit.edu/hops