PDS_VERSION_ID = PDS3 RECORD_TYPE = STREAM OBJECT = TEXT PUBLICATION_DATE = 2015-08-04 NOTE = "Description of contents of EXTRAS directory" END_OBJECT = TEXT END The EXTRAS directory contains additional files provided by data preparer for a better understanding of the data and data processing. The .AUX files in the folder ESOC, and the .LOG files in the subfolder VRA are ASCII files. More information see below. The files evolved as the mission progressed; users should refer to the files on the most recent (highest numbered) archive volume for the most up-to-date information. Files on early volumes may be only 'place-holders.' Structure of the EXTRAS directory: EXTRAS | |- ANCILLARY | | | |- ESOC - OASW | | | | | |- DATA Relevant DDS-files to describe the | | observation geometry | | (Orbit- and Attitudefiles for example). | | | | | | | |- SPICE Relevant SPICE Kernels to describe the obser- | | | vation geometry. For further details on each | | | subfolder look into AAREADME.TXT in each | | | subfolder. | | |- EK | | |- FK | | |- IK | | |- LSK | | |- ORBNUM | | |- PCK | | |- SCLK | | |- SPK | | | | | |- UNI_BW Relevant PREDICT files from the UNI BW, | | Munich. | |- VRA | | | | | |-LOGFILES These are LOGFILES which contain | | information about the level 2 Doppler and | | Ranging data processing. These filenames have | | file extension .LOG (these are text files) | | and they have except for the file | | extension the same file names as the | | corresponding Level 2 data files. | | If unfortunately no X- or S-band is available | | for one measurement (but the processing software | | requires one), a X- or S-band file from another | | day is used. Therefore, the residuals and their | | corresponding standard deviations may have strange | | values, which are not correct. This is also | | documented in the LOGFILES. | | It is possible that the differential Doppler | | has very bad values (e.g. high noise level) for | | Gravity measurements, and can therefore not be | | used for Plasma corrections. The measurement is | | then processed like an Occultation measurement | | using the Klobuchar Coefficients for correction. | | This is the reason why in the LOGFILES sometimes | | Occultation is written although this is a Gravity | | measurement. | | | | | |- SUE | | | | | |- SPICE Modified Spice kernels combined with JPL | | | | | |- DSN | | | | | |- EOP Earth Orientation Parameter files | | |- OPT Orbit propagation and timing File | | |- LIT Light time files For further information about ESOC flight dynamics orbit or attitude files and accompanying software please refer to ftp://ssols01.esac.esa.int in folder pub/data/ESOC/VEX. Additional information: ======================= EXTRAS | |- ANCILLARY | | | |- ESOC - OASW | | | | | |- DATA Relevant DDS-files to describe the | | observation geometry | | (Orbit- and Attitudefiles for example). contains ancillary data in ASCII format with extension AUX: i.e. The file format is described in the DDID Appendix H. A copy of the latest DDID Appendix H can be found in DOCUMENT/ESA_DOC/ ======================================= Spacecraft Attitude Data; reconstructed --------------------------------------- Original file name: ATNV_FDxVMx_DARyymmddhhmmss_vvvvv.VEX New Radio Science and PDS compliant file name: V00ESOCL1A_ATR_yydddhhmm_vv.AUX ======================================= Spacecraft orbit Event File --------------------------------------- Original file name: EVTV_FDxVMx_DA______________vvvvv.VEX New Radio Science and PDS compliant file name: V00ESOCL1A_EVT_yydddhhmm_vv.AUX The time information in the Radio Science file name will be set to the last time the event file contains. ======================================= HELIOCENTRIC CRUISE ORBIT FILE --------------------------------------- Original file name: ORHV_FDxVMx_DA______________vvvvv.VEX New Radio Science and PDS compliant file name: V00ESOCL1A_OHC_yydddhhmm_vv.AUX The data source identifier is set to tttt = ESOC, the data type identifier is set to sss = OHC for the heliocentric cruise orbit file. The sequence number is equal to the version number of the original file name. The extension is set to eee = AUX. ======================================= VEX VENUS CENTRIC ORBIT FILE --------------------------------------- File name Original file name: ORVV_FDxVMx_DA_yymmddhhmmss_vvvvv.VEX New Radio Science and PDS compliant file name: V00ESOCL1A_OVO_yydddhhmm_vv.AUX The data source identifier is set to tttt = ESOC, the data type identifier is set to sss = OVO for the venuscentric operational orbit file. The sequence number is not equal to the version number of the original file name. Instead they get a new chronological sequence number. OVO files always cover a month of orbit data and get frequently updated. Therefor the first file from ESOC that covers a specific file gets after renaming the sequence number _00 and when an updated OVO is received the new file will get the same file name as the first file but the sequence number is increased by one and so on. Utimately only the files with the higest version numbers will be archived since these contain the latest orbit information. The extension is set to eee = AUX. =========================================== Additional information for: | |- UNI_BW Relevant PREDICT files from the UNI BW, | | Munich. --------------------------------------------------------------------- Specification document MEX-MRS-IGM-DS-3039 or ROS-RSI-IGM-DS-3121 or VEX-VRA-IGM-DS-3014 Radio Science Predicted and Reconstructed Orbit Data: Specifications The Doppler and range predict file is provided by UniBwM and contains predicted Doppler and range for a given time span for one-way and two-way data. File name The predict file name is formatted by setting the archiving level to lll = L02 and the file type to sss = PTW or sss = PON for two-way or one-way data, respectively. The file source is set to tttt = UNBW. The predict file is always relative to a given ground station (topocentric). rggUNBWL02_sss_yydddhhmm_qq.TAB File format Two-way Doppler and range predict files column| description | unit |resolution ======================================================== 1 |sample number -------------------------------------------------------- 2 |year (t_TWRD) -------------------------------------------------------- 3 |UTC Time stamp in ISO |format (tTWRD) -------------------------------------------------------- 4 |UTC Time in Fractions of | | |DOY (t_TWRD) |days |1E-7 days -------------------------------------------------------- 5 |Ephemeris Time since | |J2000 (12 h 1 January 2000| |TBD) (tTWRD) |days |Integer -------------------------------------------------------- 6 |TWUL Doppler v_LOS,UL/c | |1E-14 -------------------------------------------------------- 7 |TWDL Doppler v_LOS,DL/c | |1E-14 -------------------------------------------------------- 8 |TWUL Doppler considering | |gravity fields degree and| |order l,m <= 10 | |1E-14 -------------------------------------------------------- 9 |TWDL Doppler considering | |gravity fields degree and| |order l,m <= 10 | |1E-14 -------------------------------------------------------- 10 |TW geom. range | |(r_S/C(tTWE) - r_G/S(tTWE))|km |0.1 km -------------------------------------------------------- 11 |TW range | |((r_S/C(tTWRU)-r_G/S(tTWE))+ | |((r_G/S(tTWRD)-r_S/C(tTWRU)) )|km |0.1 km -------------------------------------------------------- 12 |DLLT (t_TWRU-t_TWRD) |seconds |nsec -------------------------------------------------------- 13 |TWLT (t_TWE -t_TWRD) |seconds |nsec --------------------------------------------- One-way Doppler and range predict files column| description | unit |resolution ======================================================== 1 |sample number -------------------------------------------------------- 2 |year (t_TWRD) -------------------------------------------------------- 3 |UTC Time stamp in ISO |format (t_TWRD) -------------------------------------------------------- 4 |UTC Time in Fractions of | | |DOY (t_TWRD) |days |1E-7 days -------------------------------------------------------- 5 |Ephemeris Time since | |J2000 (12 h 1 January 2000| |TBD) (t_TWRD) |days |Integer -------------------------------------------------------- 6 |OW geom. range (r_S/C(t_OWE)| | - r_G/S(t_OWE) )| -------------------------------------------------------- 7 |One-Way Doppler v_LOS/c | |1E-14 -------------------------------------------------------- 8 |One-Way Doppler considering| |gravity fields degree and| | order l,m <= 10 | |1E-14 -------------------------------------------------------- 9 |OWLT (t_OWR - t_OWE) | seconds |nsec Nomenclature: OW one way link TW two way link UL uplink DL downlink c speed of light (c = 299,792,458 m/s) LT Light time v_LOS relative velocity between ground station and S/C (in the line of sight) r_S/C(t) Position of S/C at time t r_G/S(t) Position of ground station at time t t_OWE Time at emission of signal at S/C (one-way calculation) t_OWR Time at reception of signal at ground station (one-way calculation) t_TWE Time at emission of signal at ground station (two-way calculation) t_TWRU Time at reception of signal at S/C (two-way calculation - uplink) t_TWRD Time at reception of signal at ground station (two-way calculation - downlink) ----------------------------------------------------------------- RECONSTRUCTED DOPPLER & RANGE ORBIT FILE The Doppler and range reconstructed orbit file is provided by UniBwM and contains post-observation reconstructed Doppler and range for a given time span for one-way and two-way data. File name The orbit file name is formatted the archiving level to lll = L02 and the file type to sss = RTW or sss = RON for two-way or one-way data, respectively. The file type is set to ttt = ORB. The predict file is always relative to a given ground station (topocentric). rggUNBWL02_sss_yydddhhmm_qq.TAB The file format is the same as above =========================================== =========================================== =========================================== Additional information to | |- SUE | | | | | |- SPICE Modified Spice kernels combined with JPL | | | | | |- DSN | | | | | |- EOP Earth Orientation Parameter files | | |- OPT Orbit propagation and timing File | | |- LIT Light time files SUE |-SPICE: | Spice Kernels were produced by the ROS/MEX/VEX Flight Dynamics Team, | converted to IEEE binary format, and then distributed by the | JPL Navigation and Ancillary Information Facility (NAIF). | For more information on NAIF and SPICE see | http://pds-naif.jpl.nasa.gov/ | | The original Spice Kernels were merged with the JPL DE405 | planetary ephemeris and the ephemerides of Phobos and Deimos | for the same time interval. | DSN: Ancillary files provided by Deep Space Network |-EOP: Earth Orientation Parameter Files | | Earth Orientation Parameter files were produced by the Time | and Earth Motion Precision Observation (TEMPO) Group at JPL. | They documented and predicted Earth rotation (rate and axis). | These are ASCII files of variable length records. Each | record is delimited by an ASCII line-feed (ASCII 10). | There are both 'long'and 'short' versions. The long file covered | past motion since about 1962 and a prediction for about three | months into the future; these files have typical sizes of 1 MB. | The short file covered the most recent nine months of past motion | and a prediction for three months into the future; these files are | typically 30 kB. Each EOP file is accompanied by a PDS minimal | label | column |description |unit --------------------------------------------------------------- 1 |Modified Julian date |n/a --------------------------------------------------------------- 2 |X coordinate of polar motion |milliarcseconds --------------------------------------------------------------- 3 |Y coordinate of polar motion |milliarcseconds --------------------------------------------------------------- 4 |TAI-UT1 or TAI-UT1R |n/a --------------------------------------------------------------- 5 |TAI-UTC |seconds --------------------------------------------------------------- 6 |nutation correction dPsi |milliarcseconds --------------------------------------------------------------- 7 |nutation correction dEps |milliarcseconds --------------------------------------------------------------- |-OPT: Orbit Propagation and Timing Geometry File | |Orbit Propagation and Time Generation files contain estimates of |event timing (e.g., equator crossings) that depend on |precise knowledge of the spacecraft orbit. These are ASCII |files of variable length records. Each record is delimited |by an ASCII carriage-return (ASCII 13) line-feed |(ASCII 10) pair. File names have the form ydddeeeC.OPT where |the file name components are the same as for BCK files (above). |Each OPT file is accompanied by a PDS minimal label with file |name ydddeeeC.LBL. Typical files are based on reconstructed |spacecraft trajectories, cover a month of operation, and have |sizes less than 500 kB. | column |description |unit --------------------------------------------------------------- 1 |event title (e.g., PERIAP| |for periapsis passage) |n/a --------------------------------------------------------------- 2 |body name (e.g., MARS) |n/a --------------------------------------------------------------- 3 |spacecraft ephemeris time| | of event | |(yyyy-dddThh:mm:ss.fff format)|n/a --------------------------------------------------------------- 4 |Julian date |n/a --------------------------------------------------------------- 5 |ET-UTC |n/a --------------------------------------------------------------- 6 |orbit number |n/a --------------------------------------------------------------- 7 |time from periapsis | |(sDDDDDThh:mm:ss.fff format)|n/a --------------------------------------------------------------- 8 |Sun-Earth-probe angle |degrees --------------------------------------------------------------- |-LIT: Light Time File | |Light Time files give radio propagation time from the spacecraft to |Earth as a function of time. These are ASCII files of fixed length |records. Each record is delimited by an ASCII carriage-return |line-feed pair. File names have the form ydddeeeC.LIT where the |file name components are the same as for DKF files. An LIT file may |cover more than 365 days; so eee may be a year or more after |yddd. Each LIT file is accompanied by a PDS label. |Typical file sizes are less than 1 MB. | column |description |unit --------------------------------------------------------------- 1 |Date and time at the spacecraft| |(yy-fff/hh:mm:ss format) in UTC|n/a --------------------------------------------------------------- 2 |downlink light time (spacecraft| |to DSN station) |seconds --------------------------------------------------------------- 3 |uplink light time (DSN station | |to spacecraft) |seconds --------------------------------------------------------------- 4 |station number (03=generic) |n/a --------------------------------------------------------------- 5 |line number (starting from 1) |n/a ---------------------------------------------------------------