

GSFC VLBI Software
The GSFC VLBI group maintains many programs. Four major packages
are available for distribution.
SKED  creation of geodetic schedules
Field System  operation of VLBI stations
Calc/Solve  VLBI data analysis package
nuSolve  newest VLBI data analysis package
These programs fit into the chain of generating and analyzing geodetic sessions as follows:
 SKED is used to schedule a VLBI observing session.
 The Field System is used to control the equipment
(e.g., a station's antenna) that takes the observations during the
session.
 Correlator hardware and software is used to process the recorded
signals and to compute arrays of the complex crosscorrelation
function.
 The Haystack Observatory Postprocessing System (HOPS) is used to
process these arrays, find fringes, and calculate VLBI
observables for each scan, for each processed baseline:
the narrowband group delay, the wideband group delay,
and the phase and the amplitude of the coherence function.
 Calc/Solve is used to archive the output of HOPS into databases,
compute theoretical delays and delay rates, find adjustments to the
parameters of models by least squares estimation,
calculate solution statistics, and generate tables and plots of the
final results. Used to process single or multiple sessions.
 nuSolve is being developed as a replacement for Calc/Solve.
Currently it handles single sessions.
