The Voyager 1 Saturn reconstructed spacecraft trajectory file:

  vg1.jup.sat261.bsp

was produced by R. Jacobson of the  JPL Solar System Dynamics Group
as part of his work in improving the ephemerides of Saturn's
natural satellites. It was made using Voyager spacecraft observations
during the Saturn flyby, and also using Cassini observations of
Saturn's satellites.

NAIF has no "accuracy" information about the SPICE SPK file made
from the source file identified above.  R. Jacobson says new Voyager 1
trajectory solutions are still being frequently produced, based on new 
Cassini data, but that the changes between solutions are much smaller
than the solution uncertainties.  Jacbson has no plans for making any
kind of significantly different (better) solution.

Charles Acton/NAIF
2007 Jan 26