• 1.1 Purpose of this manual
• 1.2 Document change history
• 1.3 References

   
1. Introduction

   
1.1 Purpose of this manual

This manual is intended to give the LWS observer all necessary information with his data products. Version 5.0 of this manual describes data that was processed through version 7 of the LWS Off Line Processing software. Data processed through version 6.X of the processing is described in IDUM issue 4.0, data processed through version 5.X of the processing is described in IDUM issue 3.0, and data that was processed through version 4.X is described in issue 2.0 of the LWS IDUM.

The LWS IDUM should make the observer familiar with the LWS instrument, its operations, the output data, the calibration and the processing. To achieve this the following subjects are addressed:

• The LWS instrument and its operations
• Some characteristics of the instrument that have implications for the data.
• The calibration of the data and the accuracy
• An overview of the data processing
• A guide to the data products
• How to start with the data
• Suggested post-processing steps

Since this manual is intended to give the observer up to date information on the processing and the calibration of the LWS instrument, it will be updated regularly. Every change in the LWS offline processing, the calibration procudures or the file descriptions will be reflected in this manual. More frequently updated information can be found on the LWS instrument page on the World Wide Web: http://www.iso.vilspa.esa.es/instr/LWS.

We would also like to invite observers who have suggestions for improvements to this manual to send an email to the ISO helpdesk (helpdesk@iso.vilspa.esa.es) with these suggestions.

   
1.2 Document change history

The following changes were made between issue 4.0 (dated May 9, 1997) and issue 5.0 (dated 1 June 1998; current issue) of this document:

Section 1.1

Updated URL fro LWS instrument page

Section 4.2

Updated text, moved theoretical discussion to appendix

Section 5.3.1.2

Updated text

Section 5.4.1.1

Updated for new time dependent grating wavelength calibration

Section 5.4.1.2

Updated for new FP calibration

Section 6.1

Updated figures 6.1 and 6.2 to reflect new processing

Section 6.3.1

Added statement on the use of the LWGH file

Section 6.3.2

Updated the list of bullets

Section 6.3.4

Entire section replaced with updated text

Section 6.3.5

Updated text

Section 6.3.6

Entire section replaced with updated text

Section 6.4.2

Entire section replaced with updated text

Section 6.4.3

Entire section replaced with updated text

Section 6.4.9

Updated text

Section 6.4.10

Added section on uncertainty calculation

Section 7.2

Deleted

Section 7.3

Deleted

Section 7.4

Entire section replaced with updated text

Section 7.5

Updated text

Section 7.7

Deleted

Section 7.11

Entire section replaced with updated text

Section 7.13

Entire section replaced with updated text

Section 8.2.3.1

Updated sample list table

Section 8.2.3.6

Entire section replaced with updated text

Section 8.2.4.1

Updated Table 8.12, replaced Table 8.13 and 8.14

Section 8.2.4.3

Entire section replaced with updated text

Section 8.2.5.1

Updated text

Section 8.2.6

Entire section replaced with updated text

Section 8.2.7.1

Updated text, updated Table 8.28, replace Table 8.29

Section 8.2.7.4

Updated text

Section 8.2.7.5

Updated text

Section 8.2.8

Updated text and Table 8.30

Section 8.2.9.3

Entire section replaced with updated text

Section 8.2.9.4

Entire section replaced with updated text

Section 9.1

Updated ISAP description, added LIA description

Section 9.2

Updated Tables 9.1 and 9.2

Section 10.3

New section

Section 10.4

Old section 10.3

Section 10.5

Old section 10.4

Section 10.6

Old section 10.5

Section 10.7

Old section 10.6

Section 10.8

Old section 10.7

Section 10.9

Old section 10.8

Appendix A

Text moved from section 4.2

Appendix B

Old appendix A, updated some acronyms

The following changes were made between issue 3.0 (dated September 30, 1996) and issue 4.0 (dated May 9, 1997; current issue) of this document:

Section 1.1

Updated first paragraph, added URL for LWS instrument page.

Section 5.3.1

Deleted mixed mode observations for grating wavelength calibration, and updated the Fabry-Perot section.

Section 5.4.1

Updated with actual accuracy figures for wavelength calibration.

Section 5.4.2

Updated with actual accuracy figures for flux calibration, and added Fabry-Perot photometric accuracy.

Section 6.1

Updated figure 6.2, updated Auto Analysis description, updated Figure 6.3.

Section 6.3.1

Added LIPD file.

Section 6.3.5

Added paragraph describing glitches on first and last point in a ramp.

Section 6.3.7

Replaced with updated text.

Section 6.4.1

Replaced with updated text.

Section 6.4.2 in version 3.0

Deleted.

Section 6.4.8

Added.

Section 6.4.9

Added.

Section 7.2

Added.

Section 7.3

Added.

Section 7.4

Added.

Section 7.5

Added.

Section 7.6

Added.

Section 7.7

Added.

Section 7.8

Added.

Section 7.13

Replaces section 7.7 in version 3.0.

Section 7.14

Added.

Section 8.1

Changed LILL to LIPD file, and added LSNR, LIAC, LSCA and LGIF files to data product list.

Section 8.2.4.1

Updated table 8.13.

Section 8.2.4.2

Changed LILL to LIPD file description, deleted tables 8.15 and 8.16.

Section 8.2.4.3

Updated keywords in table 8.16.

Section 8.2.5

Updated status word description.

Section 8.2.7 in version 3.0

Deleted.

Section 8.2.8.12 in version 3.0

Deleted.

Section 8.2.7.1 (8.2.8.1 in version 3)

Updated keywords.

Section 8.2.7.2

Added.

Section 8.2.7.3

Added.

Section 8.2.7.4

Added.

Section 8.2.7.5

Added.

Section 8.2.8 (8.2.9 in version 3)

Updated status word description.

Section 8.2.10.3 in version 3.0

Deleted.

Section 8.2.9.2 (8.2.10.2 in version 3)

Changed to LCIR description.

Section 9.2

Updated table 9.1.

Section 9.3

Updated table 9.2.

Section 10.1

Updated text, added URL for MPE and IPAC.

Section 10.7

Added.

Appendix A in version 3.0

Deleted.

Appendix A

Added AAL and SPL acronyms to list.

The following changes were made between issue 2.0 (dated May 6, 1996) and issue 3.0 (dated September 30, 1996) of this document:

Chapter 0

Deleted.

Section 1.3

Added references.

Section 3.2.1.2

Complete rewrite.

Section 3.2.2

Updated TDATA description and tables.

Section 3.2.5

Included schematic diagram of raster operations.

Section 3.2.6

Replaced pseudo code by schematic diagrams.

Section 3.2.7

Replaced pseudo code by schematic diagrams.

Section 4.2 (version 2)

Removed

Section 4.2 (section 4.3 in issue 2)

Rewritten

Section 4.3 (section 4.4 in issue 2)

Rewritten

Section 4.4 (section 4.5 in issue 2)

Rewritten

Section 5.1

Rewritten

Section 5.2

Updated and rewritten

Section 5.3

Updated and rewritten

Section 5.4

Updated with more recent figures, Tables were updated.

Section 5.5 (version 2)

Moved to Chapter 8, sections 8.2.7 and 8.2.10. Updated all file descriptions following implementation of version 5 of the LWS OLP pipeline.

Section 6.1

Updated flow diagrams for Derive-SPD and Auto Analysis, rewritten paragraph on TDF first scan/Derive-ERD.

Section 6.3

Included introduction. Rewritten all sections describing the processing, following the implementation of version 5 of the LWS OLP pipeline.

Section 6.4

Rewritten all sections describing the processing, following the implementation of version 5 of the LWS OLP pipeline. Added sections for the spectral element correction and the velocity correction.

Chapter 7

Added section 7.1 (Glitches), 7.2 (Scan direction) and 7.7 (Responsivity drift correction).

Section 8.2.4

Updated file descriptions, added general and statistical keywords

Section 8.2.5

New section describing the LSPD status words.

Section 8.2.6

New section describing the LILL status words.

Section 8.2.7 (this issue)

Updated section 5.5.1 from version 2.

Section 8.2.8 (section 8.2.5 in issue 2)

Updated file descriptions, added general and statistical keywords.

Section 8.2.9

New section describing the LSAN status words.

Section 8.2.10 (this issue)

Updated section 5.5.2 from version 2.

Section 9.1

Updated

Chapter 10

Updated, more information added

Appendix A

Updated all example file headers.

   
1.3 References

This document is based on many notes and documents describing the different subsystems of the LWS instrument, the off-line processing and the calibration. The following documents are important as reference for the observer:

• Addendum to the LWS Observers Manual; version 1.0, N.Trams et al., 5 August 1996, SAI/96-166/Dc
• Baseline Requirements Document for Off Line Processing, version 2.0, 1 February 1994, ISO-SSD-9010
• ISO Data Products Document; issue 8, R.D.Saxton, 20 August 1996
• ISO Satellite Data Users Manual; version 1, K. Leech, 1 November 1995 SAI/95-218/Dc
• LWS Observers Manual; version 1.0, P.E. Clegg et al., 6 March 1994 LWS/PEC/2038.01
• LWS Telemetry Contents; version 1, K.J.King, 8 December 1992 LWS/RAL/N/2005.04