PDS_VERSION_ID = PDS3 LABEL_REVISION_NOTE = " 2014-12-04 M. Kaelberer Modified the Interferences section to include additional sources of noise and additional documentation." RECORD_TYPE = STREAM SPACECRAFT_NAME = "CASSINI ORBITER" INSTRUMENT_NAME = "COMPOSITE INFRARED SPECTROMETER" MISSION_PHASE_NAME = "SATURN TOUR" OBJECT = TEXT INTERCHANGE_FORMAT = ASCII PUBLICATION_DATE = 2015-01-01 NOTE = "CASSINI CIRS TSDR AND SPECTRAL CUBE ARCHIVE" END_OBJECT = TEXT END Volume COCIRS_* Cassini Composite Infrared Spectrometer Data Archive AAREADME.TXT 20 June 2005 Last Updated on 15 October 2014 C.A Nixon & N. Gorius Cassini CIRS Team University of Maryland Catholic University of America NASA GSFC ======================================================================= INTRODUCTION ======================================================================= Welcome to the Cassini CIRS Archive Volume. CIRS is the Composite Infrared Spectrometer on-board the Cassini spacecraft mission to Saturn. This volume contains Cassini CIRS TSDRs (Time-Sequential Data Record), Spectral Image Cubes, and documentation which describes the TSDRs and the Cubes. Both the uncalibrated data (interferograms) and calibrated spectra are on each archive volume. Documentation includes a description of the instrument observing strategies and data-taking modes (DATASET.CAT and SSR review paper), the archive volume layout (VOLSIS.TEX), the data formats (DATASIS.TEX CUBESIS.TEX) and the calibration process. A simple database tool 'Vanilla' is normally used to access the data, which is stored in binary format. The source code (C-language) for Vanilla and sample executables are included on this volume. You do not have to use Vanilla to access the data: a description of the binary data structures is given in the DATASIS.TEX document to enable you to read the data yourself if you prefer. ======================================================================= VOLUME INFORMATION ======================================================================= top-level directory | |- AAREADME.TXT | |- ERRATA.TXT | |- VOLDESC.CAT - PDS .CAT files; ASCII text information files | relating to mission, instrument, spacecraft etc | |- [CALIB] | | | |- CALINFO.TXT | | | |- 2000_nesr_fpX_NNpNNcm-1.txt - 15 Files (X=1,3,4, NNpNN = | 0p5, 1p0, 2p8, 6p6, 15p5) | containing the spectral noise | equivalent spectral radiance | for the specified focal plane and | spectral resolution. | |- [CATALOG] | | | |- CATINFO.TXT | | | |- CIRSREF.CAT | | | |- DATASET.CAT | | | |- INST.CAT | | | |- INSTHOST.CAT | | | |- MISSION.CAT | | | |- PERSON.CAT | | | |- PROJREF.CAT | |- [DATA] - CIRS science data | | | |- DATAINFO.TXT | | | |- [TSDR] - Time Sequential Data Record | | | | | |- TSDRINFO.TXT | | | | | |- [APODSPEC] | | | | | |- [HSK_DATA] | | | | | |- [NAV_DATA] | | | | | |- [UNAPSPEC] | | | | | |- [UNCALIBR] | | | | | |- [CUBE] - Spectral Image Cube | | | |- CUBEINFO.TXT | | | |- [EQUIRECTANGULAR] | | | |- [POINT_PERSPECTIVE] | | | |- [RING_POLAR] | |- [DOCUMENT] - documentation provided by the CIRS team | | | |- DOCINFO.TXT | | | |- DATASIS.TEX/.PDF - description of the TSDR data types and formats | | | |- CIRS-USER-GUIDE.PDF - CIRS User Guide | | | |- CUBESIS.TEX/.PDF - description of the Spectral Image Cube types and | | formats | | | |- VOLSIS.TEX/.PDF - description of the volume format and layout | | | |- CIRS_FOV_OVERVIEW.TXT/.PDF - description of the CIRS fields of view | | | |- cirs_cal_equations.doc/.pdf - document describing calibration math | | | |- cirs_interferences.pdf - description of CIRS instrument interference | | sources and their handling (2005) | | | |- CirsNoise.pdf - an update on CIRS noise sources (2014) | | | |- vanilla_fields.asc - list and description of CIRS vanilla database | | fields | | | |- [*.ps/*.eps/*.tiff] - miscellaneous diagrams and drawings of CIRS: | see the DOCINFO.TXT for details. | |- [EXTRA] | | | |- EXTRINFO.TXT | | | |- [SURFTEMP] | | | | | |- [TITAN] | | | | | |- README.TXT - description of the Titan surface temperature | | | maps | | | |- [VERTPROF] | | | | | |- AAAREADME.TXT - description of the temperature, aerosol, and | | | ice profile retrievals | | | |- [CUBE_OVERVIEW] - images providing an overview of the content | | of the Spectral Image Cube | | | |- [EQUIRECTANGULAR] | | | |- [POINT_PERSPECTIVE] | | | |- [RING_POLAR] | | |- [INDEX] - PDS index files | | | |- INDXINFO.TXT | | | |- TSDR_CUMINDEX.TAB | | | |- TSDR_INDEX.TAB | | | |- CUBE_EQUI_CUMINDEX.TAB | | | |- CUBE_EQUI_INDEX.TAB | | | |- CUBE_POINT_CUMINDEX.TAB | | | |- CUBE_POINT_INDEX.TAB | | | |- CUBE_RING_CUMINDEX.TAB | | | |- CUBE_RING_INDEX.TAB | |- [SOFTWARE] - Vanilla software | | | |- SOFTINFO.TXT | | | |-[BIN] | | | |-[DOC] | | | |-[SRC} ======================================================================= QUICK START - BEGINNING TO USE THE TSDR DATA ======================================================================= For a quick start, it would be helpful to first familiarize oneself with the two SIS (Software Interface Specification) documents in the DOCUMENT directory: - the Data SIS (DATASIS.PDF) describes the TSDR data in the archive - the Volume SIS (VOLSIS.PDF) describes the layout of this volume There is a lot of other useful information in the various files in this directory. All the science data on this volume is stored in binary files, hence a tool is needed to extract into ASCII form. The usual data query and extraction tool, called Vanilla, is included in the SOFTWARE area of this volume, both as executable for several architectures, and source code. Proceed to the SOFTWARE/DOC directory and browse the Vanilla Users Guide and CIRS Vanilla Examples Documents. To begin using Vanilla, you should look at SOFTWARE/BIN and see if compatible executables exist for your system. If not, you may wish to go to SOFTWARE/SRC/VANILLA and attempt to compile Vanilla on your system. Or, you may prefer to read the binary data yourself. This is fairly straightfoward, as the binary file layouts are described in detail in the Data SIS, so it should be relatively easy to write a simple subroutine on your machine to read in binary records. Binary files occur in two types: fixed record length (.DAT type) and variable length record type (.VAR type) files. Read the Data SIS carefully before attempting to read the data, and look at some of the Vanilla source code for guidance. When interrogating the database, you will find the *_SUM.TAB files in the INDEX directory useful for determining the times of different observations. Also note that there is a utility for converting back and forth to/from SCET time and ASCII time whose source code is found in Appendix B of the Data SIS. Finally, note that the main directories all have a INFO.TXT file which describes the most important files residing there. ======================================================================= QUICK START - BEGINNING TO USE THE SPECTRAL IMAGE CUBES ======================================================================= The Spectral Image Cubes format is described in the Cube SIS (CUBESIS.PDF) located in the DOCUMENT directory. Once you have read this document, accessing the data should be fairly straightforward. Note that the Cubes are derived from the TSDR database. Therefore you may also be useful to be familiar with the Data SIS documents prior to use the Cubes. ======================================================================= DISK FORMAT ======================================================================= This disk is formatted according to the ISO-9660_LEVEL2 standard. ======================================================================= FILE FORMATS ======================================================================= CATALOG FILE FORMAT .CAT files. Found in the ROOT and CATALOG directories. Object oriented structure: `keyword = value'. All lines terminated with carriage return and line feed characters. DOCUMENT FILE FORMAT .TXT and .PDF suffixes. Found in all top-level directories. TXT-suffix files are ASCII files with embedded PDS labels. Lines are terminated with carriage return and line feed characters. PDF files are binary files written in the Portable Document Format, a proprietary format of Adobe Software Inc. PDS LABEL FORMAT PDS labels are object-oriented structures consisting of `keyword = value' statements. PDS labels are detached from the associated file ( .LBL extension). Lines are terminated with the carriage return and linefeed characters. SOFTWARE FORMAT Computer code is written in ANSI C or PERL. Executable binary files are precompiled for the Linux operating system on the i686 platform. Some programs (those related to Vanilla and other data extraction tools) are also compiled for Sun Solaris on UltraSPARC. TABULAR FILE FORMAT File suffixes are .TAB, .ASC, .DAT and .VAR. Files are either ASCII or binary. ASCII files ( .TAB and .ASC) are found in the INDEX directory. These files are formatted for direct reading into many database management systems on various operating systems. Fields are enclosed by double quotes, and separated by commas. Character fields are left justified and padded to a constant length with spaces if required (.TAB only). Numeric fields are right justified. The 'start bytes' and 'bytes' values listed in the labels count data only, not quotes, commas or external spaces. The records are fixed length and terminated by the carriage return and line-feed characters. Binary tables end in .DAT (fixed length data fields) and .VAR (variable length data fields), and are found in the DATA and CALIB directories. If a .VAR data file exists, it is always accompanied by a .DAT file, but the latter may exist alone. .DAT files contain pointers to data items in the associated variable field length data files. ======================================================================= INTERFERENCES ======================================================================= CIRS interferogram data suffers from a number of external interferences, especially: - an 8 Hz spike pattern due to spacecraft communications and also to the onboard numerical filtering. - a 1/2 Hz spike pattern due to the Bus Interface Unit, transfer of data. - a sine wave of variable frequency which appears correlated with the electronics board temperature. - scan speed fluctuations which have been traced to two mechanical vibrations on the spacecraft: (a) the MIMI LEMMS actuator (b) the reaction wheels used to turn the spacecraft. - a 1 Hz spike pattern from the analog multiplexor data readouts. - an 8.3 Hz spike pattern from an unknown source. These various effects, plus the onboard and on-ground processing done to mitigate them, are described in more detail in the cirs_interferences.pdf, CIRS-USER-GUIDE.PDF, and CirsNoise.pdf documents found in the DOCUMENT directory. ======================================================================= ERRATA AND DISCLAIMER ======================================================================= A cumulative list of anomalies and errors is maintained in the file ERRATA.TXT at the root directory of this volume. Although considerable care has gone into making this volume, errors are both possible and likely. Users of the data are advised to exercise the same caution as they would when dealing with any other unknown data set. Reports of errors or difficulties would be appreciated. Please contact one of the persons listed herein. ======================================================================= WHOM TO CONTACT FOR INFORMATION ======================================================================= For questions concerning this volume set, data products and documentation: Conor Nixon NASA Goddard Space Flight Center Code 693 Solar System Exploration Division Planetary Systems Lab Greenbelt, MD 20771 301-286-6757 conor.nixon@gsfc.nasa.gov For questions concerning the spectral image cubes and their documentation: Nicolas Gorius NASA Goddard Space Flight Center Code 693 Solar System Exploration Divsion Planetary Systems Lab Greenbelt, MD 20771 301-286-0021 nicolas.gorius@nasa.gov For questions concerning how to read the volume: James Tingley NASA Goddard Space Flight Center Code 693 Solar System Exploration Division Planetary Systems Lab Greenbelt, MD 20771 301-286-4980 james.tingley@gsfc.nasa.gov For questions concerning the PDS labels: Paul Schinder NASA Goddard Space Flight Center Code 693 Solar System Exploration Division Planetary Systems Lab Greenbelt, MD 20771 301-286-1393 paul.schinder@gsfc.nasa.gov For other PDS enquiries: Lyle Huber New Mexico State University La Cruces, NM 88003 lhuber@nmsu.edu This submission was produced by James Tingley, Conor Nixon and Nicolas Gorius with contributions from Ever Guandique, Andrei Mamoutkine, and Monte Kaelberer.