CCSD3ZF0000100000001NJPL3IF0PDSX00000001 PDS_VERSION_ID = PDS3 RECORD_TYPE = STREAM SPACECRAFT_NAME = MAGELLAN TARGET_NAME = VENUS OBJECT = TEXT PUBLICATION_DATE = 1994-07-01 NOTE = "MAGELLAN ALT-EDR ARCHIVE CD-WO" END_OBJECT = TEXT END MAGELLAN ALT-EDR ARCHIVE CD-WO 1. Introduction This CD-WO contains Magellan ALT-EDR (Altimeter Experiment Data Record) products. It also contains documentation files which describe the ALT- EDRs. Each ALT-EDR data directory contains the raw altimeter data returned from one orbit and the ancillary files necessary to understand the data. The ALT-EDR products archived on this volume are the exact products released by the Magellan Project. Errors and anomalies are noted where detected. Supporting documentation and label files conform to the Planetary Data System (PDS) Standards, Version 3.0, Jet Propulsion Laboratory (JPL) document JPL D-7669. 2. Disk Format The disk has been formatted so that a variety of computer systems (e.g. IBM PC, Macintosh, Sun) may access the data. Specifically, it is formatted according to the ISO 9660 level 1 Interchange Standard. For further information, refer to the ISO 9660 Standard Document: RF# ISO 9660-1988, 15 April 1988. 3. File Formats Each orbit for which ALT-EDR data exist is represented by a set of 11 files: ALT.DAT - Altimeter burst buffer records CLK.DAT - SCLK/SCET conversion coefficients DCM.DAT - Decommutation and decalibration data DQS.DAT - EDR Data Quality Summary ENG.DAT - Engineering data EPH.DAT - S/C ephemeris file ERR.TXT - Errors reported by the label generator HDR.DAT - Orbit Header MON.DAT - DSN monitor records QTN.DAT - Quaternion pointing coefficients SAB.DAT - Radar header records Each file (except ERR.TXT) is paired with a detached PDS label file that describes its contents. Further information on ALT-EDR file formats and contents can be obtained from the Magellan Software Interface Specification document TPS-101, "SAR and Altimeter EDR/TEDR Tapes", Betsy Wilson, JPL, Rev. D, March 15, 1989. All document files (*.TXT) and detached label files (*.LBL) contain 80-byte fixed-length records, with a carriage return character (ASCII 13) in the 79th byte and a line feed character (ASCII 10) in the 80th byte. The first two lines are an exception: the first contains a 40-byte SFDU aggregate label, followed by a carriage return and a line feed. The second contains 36 space characters (ASCII 32) followed by a carriage return and a line feed. The first PAIR of lines is therefore 80 bytes long, and all remaining lines are offset from the start of the file by a multiple of 80 bytes. This allows the files to be read by the MacOS, DOS, Unix, and VMS operating systems. The PDS label file has the same name as the data file it describes, with the extension .LBL. PDS labels are object-oriented. The object to which the label refers (e.g. IMAGE, TABLE, etc.) is denoted by a statement of the form: ^object = location in which the carat character (^, also called a pointer in this context) indicates that the object starts at the given location. In an embedded label, the location is an integer representing the starting record number of the object (the first byte in the file is byte 1 of record 1). In a detached label, the location denotes the name of the file containing the object, along with the starting record or byte number. For example: ^TABLE = ("ENG.TAB",309) indicates that the TABLE object begins at byte 309 of the file ENG.TAB, in the same directory as the detached label file. Below is a list of the possible formats that use the ^object keyword. ^object = n ^object = n ^object = ("filename.ext",n) ^object = ("filename.ext",n) where n is the starting record or byte number of the object, counting from the beginning of the file (record 1, byte 1). indicates that the number given is in units of bytes. filename is the upper-case file name. ext is the upper-case file extension. 4. CD-ROM Contents The files on this CD-ROM are organized in one top-level directory with several subdirectories. The following table shows the structure and content of these directories. In the table, directory names are enclosed in square brackets ([]), upper-case letters indicate an actual directory or file name, and lower-case letters indicate the general form of a set of directory or file names. FILE CONTENTS Top-level directory | |- AAREADME.TXT The file you are reading. | |- ERRATA.TXT Overview of errors on this, and previous, | volumes of ALTEDRCD products. | |- VOLDESC.CAT A description of the contents of this CD-ROM | volume in a format readable by both human and | computers. | |- [CATALOG] A directory containing information about the | | Magellan ALT-EDR dataset. | | | |- CATINFO.TXT Description of contents of the CATALOG directory. | | | |- ALTEDRDS.CAT PDS dataset catalog object | | | |- INSTHOST.CAT PDS spacecraft catalog object | | | |- MISSION.CAT PDS mission catalog object | | | |- PERSONEL.CAT PDS personnel catalog object | | | |- REFS.CAT PDS reference catalog object | | | `- RDRSINST.CAT PDS instrument catalog object | |- [DOCUMENT] A directory containing document files relating | | to this disk. | | | |- DOCINFO.TXT Description of contents of the DOCUMENT directory. | | | |- ALTEDRCD.TXT A machine readable version of the MIT-MGN-ALTEDRCD | | SIS document describing the format and content of | | the Magellan ALT-EDR Archive CD-WO data files. | | | |- ALTEDRCD.LBL Description of ALTEDRCD.PS. | | | `- ALTEDRCD.PS A copy of ALTEDRCD.TXT in PostScript format, | suitable for previewing on a high-resolution | graphics terminal or direct printing on a | laser printer or photo-typesetter. | |- [INDEX] A directory containing information about the | | contents of this CD-WO volume. | | | |- CUMINDEX.LBL Description of CUMINDEX.TAB. | | | |- CUMINDEX.TAB Cumulative index of all ALT-EDR archive data files. | | | |- INDEX.LBL Description of INDEX.TAB. | | | |- INDEX.TAB Index of ALT-EDR archive data files on this volume. | | | `- INDXINFO.TXT Description of the contents of the INDEX directory. | `- [Annnn_vv] Directories containing ALT-EDR data files for | orbit `nnnn', version `vv'. | |- ALT.DAT Altimeter burst record file |- CLK.DAT SCLK/SCET conversion coefficients |- DCM.DAT Documentation and decalibration data |- DQS.DAT EDR Data Quality Summary |- ENG.DAT Engineering data |- EPH.DAT S/C ephemeris file |- ERR.TXT Errors reported by the label generator |- HDR.DAT Orbit Header |- MON.DAT DSN monitor records |- QTN.DAT Quaternion pointing coefficients |- SAB.DAT Radar burst header records `- nnn.LBL PDS labels for the DAT files 5. Whom to Contact for Information For questions concerning this volume set: Peter G. Ford Center for Space Research Building 37 Room 601 Massachusetts Institute of Technology 70 Vassar Street Cambridge, MA 02139 Telephone: 617-253-6485 Datafax: 617-253-0861 Internet: pds-requests@space.mit.edu URL: http://delcano.mit.edu/ 6. Cognizant Persons Magellan Dr. Raymond Arvidson Archive Project Washington University Coordinator St. Louis, MO ALT-EDR Data Dr. Peter Ford MIT 37-601 Volume generation, Peter Ford and Joan Quigley validation, labels, MIT catalog templates, Cambridge, MA documentation This disk was produced at MIT by Peter Ford and Joan Quigley.