PDS_VERSION_ID = PDS3
LABEL_REVISION_NOTE   = "VERSION 1, RDR, 2006-05-22"
RECORD_TYPE = STREAM
OBJECT = TEXT
  INTERCHANGE_FORMAT  = ASCII
  PUBLICATION_DATE = 2006-05-22
  NOTE = "Description of the GEOMETRY directory contents for the HUYGENS DWE
data set"
END_OBJECT = TEXT
END

This directory contains the following files (and the associated labels):

HUYGENS_STATE.TAB: the state vector components of Huygens in the IAU-Titan
frame used for the computation of the DWE projection angles. The time column
is given as SCET, which is reconstructed from Earth Received Time of the
corresponding Doppler sample and the one-way light time between the receiving
antenna and the Titan center. As Huygens is less than 3000 km away from the
Titan center at any given time during the mission, the timing error of this
approximation is less than 0.01 sec.

ANTENNA_STATE.TAB: the state vector components of the receiving antenna used
for the computation of the DWE projection angles. The position vectors are
given in the IAU-Titan frame, to simplyfy vector addition with the Huygens
position vectors. The time column is given as Earth Received Time to account
for retardation. The velocity components are given in the J2000 frame centered
at Titan, because IAU-Titan is a non-inertial frame (co-rotating with Titan).
This velocity is used to compute the special relativistic effect on the
received sky frequency. The error induced by ignoring the velocity of Huygens
relative to Titan in this computation of the order of 10^(-13) (below
mHz-range at S-Band).

ANGLES.TAB: DWE projection angles used for the computation of the zonal wind
speed.