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Дата изменения: Tue Nov 23 01:09:17 2004
Дата индексирования: Sat Dec 22 07:40:59 2007
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Поисковые слова: spacecraft

XMM-Newton Science Analysis System


tools (tools-1.58.1) [xmmsas_20041122_1834-6.1.0]

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tcsfix: Time Correlation Spacecraft file FIXing task

• SYNOPSIS
  
      tcsfix [clonetcs=yes|no] [rerun=yes|no]
  
• DESCRIPTION
  This task fixes a number of distinct problems in ODF time correlation data:
  1. Due to wrong ground station and spacecraft time propagation delays hardcoded in XSCS$<=$v71 all time correlation files produced with these XSCS versions contains too small UTC values. The absolute error is - depending slightly on the GS ID - of the order of 60ms. In addition some of the early TCS files do not contain the ERTIMRAW column that hold the non-propagation delay corrected earth reception times. Also, some early TCS have bogus entries with UTCDAY=0 - those rows are removed from the table.
  2. During revolutions 384 - 394 (both inclusive) the Santiago ground station clock was running exactly one second ahead of UTC. Consequently, the time correlation data show a corresponding discontinuity at the time of a station handover to Santiago (GSID==41).
  3. During several periods in 2002 timing data from the Kourou ground station showed various anomalies which manifests themselves as discontinuities at the time of a handover to/from this station.
  tcsfix does:

   ${}$

  remove rows where UTCDAY=0

   ${}$

  add the ERTTIMRAW column to the TCS unless it exists already

  C1

  if (rev < 207)

  • undo the wrong propagation delays to all UTC fields and applies the correct delays

  C2

  if (rev $>=$ 384 && rev $<=$ 394)

  • subtract 1s to UTC data from Santiago station

  C3

  if (observation start/end time lies in a Kourou bad-time window)

  • correct anomalies

   ${}$

  adds attribues
  TCSFIXED = T // this TCS has been fixed
  TCSFIXV = M.m.p // tcsfix version number
  TCSFIXC = id // numerical code of applied corrections
  

  C1 is only done if the revolution number is less than 207 (XSCS-v72 was put online at the beginning of rev 207); C2 is only done for ODFs from revolutions $[384, 394]$; C3 is only done if observation start/end time lies within affected time windows. C1/C2/C3 are not performed if the attribute TCSFIXC indicates that these corrections have been applied already in a previous run (to avoid double-correction through repeated invocations of tcsfix. Each set bit in TCSFIXC stands for one distinct applied correction, i.e. TCSFIXC=0 indicates that the data has not been modified.