| DATA_SET_DESCRIPTION |
Data Set Overview
=================
The second Cassini Gravitational Wave Experiment (GWE2) Raw Data
Archive is a time-ordered collection of radio science raw data
acquired during the Space Science subphase of the Cassini mission.
The DATA_SET_ID 'CO-X-RSS-1-GWE2-V1.0' includes the following
components:
Instrument host (i.e., 'CO' for CASSINI ORBITER)
Target (i.e., 'X' for Other)
Instrument (i.e., 'RSS' for Radio Science Subsystem)
Data processing level number (i.e., '1')
Description (i.e., 'GWE2')
Version number (i.e., 'V1.0')
Two types of measurements were obtained; these are known
as closed-loop and open-loop recordings. The closed-loop
system uses a phase-lock loop in the receiver to track the
downlink signal, reporting both amplitude and frequency 10
times per second. In the open-loop system, the signal is
simply converted to a baseband frequency range; the entire
passband is sampled and recorded at 1000 samples per second.
The data set includes three primary data types. Archival Tracking
Data Files (ATDFs or TDFs) are the most primitive (and most
voluminous) product of the closed-loop system. Orbit Data Files
(ODFs) are compressed versions of ATDFs, specifically targeted to
spacecraft navigators and scientists interested in gravity fields.
Radio Science Receiver (RSR) files are the primary data type from
the open-loop system.
Parameters
==========
The ATDF is the primary output from the Cassini closed-loop system.
Each ATDF in the data set is accompanied by a full PDS label which
defines both the content and the format (at the bit level) of the
file. ATDF data fields include:
High- or low-rate Doppler
Range
Uplink frequencies (ramps)
Differential Range vs Integrated Doppler (DRVID)
Allan deviation
Smoothed noise
Other information in ATDF data records includes sample date and
time; spacecraft ID; ground station and its configuration;
status flags and values reported by various ground systems;
calibration values, noise estimates, and tolerances (station
delay, transmitter power, etc.); and signal strength.
The ODF is a compressed version of the ATDF. It contains the most
important information (range, Doppler and frequency ramps) needed by
spacecraft navigators, and investigators interested in determining
gravitational fields. Each ODF is accompanied by a full PDS label
which describes both the content and format of the associated file.
ODF data fields include:
One-way Doppler (Hertz)
Two-way Doppler (Hertz)
Three-way Doppler (Hertz)
SRA planetary operational discrete spectrum range (range
units)
The Radio Science Receiver (RSR) files are the primary output
from the Cassini open-loop system and they contain 16-bit samples
of receiver output. Each RSR file is accompanied by a full PDS label
which describes both the content and format of the file at the
bit level.
Processing
==========
The open-loop Radio Science Receiver (RSR) files are screened for
gaps. No gaps were found in the RSR files for GWE2.
ATDFs are screened for data/contents problems, which are corrected
if/as possible before the files are released by the JPL multimission
Radio Metric Data Conditioning Team (RMDCT).
ODFs are abstracted from subsets of ATDF data by the RMDCT.
The closed-loop Tracking Data Files (TDFs = ATDFs) and Orbit Data
Files (ODFs) for Cassini GWE2 are constructed to contain the data
for a single day (approximately). Specifically, the file for any
day consists of the Goldstone data (which started around 0-hour of
that day, but possibly as much as 2 hours earlier), the subsequent
Canberra data (which occurred around midday), and the Madrid data
(which occurred during the final several hours of the day, but
possibly into the next day) through end of track. This results
in two items that require special attention when processing the
TDF data files:
1. There are extraneous Madrid data at the beginning of the
file (which overlap Goldstone data, by about 20 minutes)
that can not be processed because the required uplink
information (ramps table) is not present -- these same
Doppler data are present, and must be processed, on the
preceding day's TDF (at the end).
2. Likewise, the 3-way Doppler for Goldstone at the beginning
of the file can not be processed because it, too, requires
the Madrid uplink information; and must, therefore, also
be processed on the preceding day's TDF (at the end).
This is presented graphically in the following diagram (where ':'
denotes station Transmitter handover):
ATDF Contents:
--------------
3-way 2-way
|-:---|----:-|
Canberra
3-way 2-way 3-way
|-:---|---------------------------:-| |-:---|...
Goldstone Goldstone
2-way 3-way 2-way
...:-| |-:---|---------------:-|
Madrid Madrid
Processing:
-----------
N-1 N+1
------>| N (^^^^^|-->
(^^^^^|----------------------------------------------------------->|
u/l ~24 hours
Primary Data
============
The primary data are stored on DVD volumes in subdirectories TDF,
ODF, and RSR in per-day directories GWE2_ddd (where ddd specifies
the day of year based on the start time of the data). Users should
refer to the INDEX/CUMINDEX.TAB listing to locate primary data files.
ATDFs are stored in the TDF directory on archival volumes.
File names are of the form sssttaayyyy_ddd_hhmmxuuwVn.TDF,
where 'sss' is the sequence/orbit id (e.g., C35), 'tt' is the
target id (e.g., EA),'aa' is the activity/experiment id (e.g., GW),
'yyyy_ddd_hhmm' is the date and time for the start of included data
(e.g., 2002_340_0330), 'xuu' is the transmitter band and uplink
station (e.g., K25), 'w' is the ground mode or 'way'
(e.g., 2 for 2-way) and Vn is the file version number (e.g., V1).
The PDS label has file name sssttaayyyy_ddd_hhmmxuuwVn.LBL.
The typical ATDF contains about 46 Mbytes.
ODFs are stored in the ODF directory on archival volumes.
File names are of the form sssttaayyyy_ddd_hhmmxuuwVn.ODF.
The PDS label has file name sssttaayyyy_ddd_hhmmxuuwVn.LBL.
The typical ODF contains about 3 Mbytes.
RSR files are stored in the RSR directory on archival volumes.
File names are of the form sssttaayyyy_ddd_hhmmxuudrrD.rcs,
where 'drr' is the downlink band and receiving station (e.g., K25)
and 'rcs' is the RSR, channel and subchannel that were used to
collect the data (e.g., 1A1). The PDS label has file name
sssttaayyyy_ddd_hhmmxuudrrD.LBL. The typical RSR contains from
about 30 Mbytes to about 165 Mbytes depending Doppler mode and
station (i.e., track duration).
Secondary Data
==============
Secondary data are needed for proper analysis and interpretation
of the radio data (file types TDF, ODF, and RSR). Secondary data
that cover a time span of less than 24 hours are stored in
subdirectories of GWE2_ddd (i.e., 158, 515, PD1, PD2 and TLM).
Secondary data that cover a time span greater than 24 hours are
provided in subdirectories CKF, EOP, ION, SPK and TRO in the
GWE2_ANCILLARY directory. Users should refer to the
INDEX/CUMINDEX.TAB listing to locate secondary data files.
0158-Monitor Files (158 Directory)
---------------------------------------------------
0158-Monitor files are ASCII files with names
sssttaayyyy_ddd_hhmm_hhmmrr.158 where 'hhmm_hhmm' is the start
and end time of the file and 'rr' is the receiving station.
They are channelized DSN Monitor Data files (new format) and
they are produced at JPL by a Query Server operating on DSN Monitor
packets stored in the JPL Telemetry Delivery System (TDS) Data
Base. Each 0158-Monitor file is accompanied by a PDS label
with file name sssttaayyyy_ddd_hhmm_hhmmrr.LBL. Typical file size
is 10 MB. The available 0158-Monitor channels, their names, and
definitions are:
0158-Monitor Name Definition
Channel #
M-0804 AZESTMP1 Average monopulse receiver estimated
azimuth error - first second
M-0805 ELESTMP1 Average monopulse receiver estimated
elevation error - first second
M-0806 AZESTMP2 Average monopulse receiver estimated
azimuth error - second second
M-0807 ELESTMP2 Average monopulse receiver estimated
elevation error - second second
M-0808 AZESTMP3 Average monopulse receiver estimated
azimuth error - third second
M-0809 ELESTMP3 Average monopulse receiver estimated
elevation error - third second
M-0810 AZESTMP4 Average monopulse receiver estimated
azimuth error - fourth second
M-0811 ELESTMP4 Average monopulse receiver estimated
elevation error - fourth second
M-0812 AZESTMP5 Average monopulse receiver estimated
azimuth error - fifth second
M-0813 ELESTMP5 Average monopulse receiver estimated
elevation error - fifth second
M-0814 AZCORMP Accumulated azimuth correction
M-0815 ELCORMP Accumulated elevation correction
M-0816 AALPHA Aberration angle off boresight
M-0817 ABETA Aberration clock angle of uplink beam
M-0818 CNSCNTYP Conscan type
M-0819 RCVSNR Monopulse Receiver SNR
M-0820 ABCX Aberration table x-position
M-0821 ABCY Aberration table y-position
M-0822 ABER Aberration correction
MON-5-15 Files (515 Directory)
---------------------------------------------------
MON-5-15 files are ASCII files with names
sssttaayyyy_ddd_hhmm_hhmmrr.515 where 'hhmm_hhmm' is the start
and end time of the file and 'rr' is the receiving station.
They are channelized DSN Monitor Data files (old format) and they
are produced at JPL by a Query Server operating on DSN Monitor
packets stored in the JPL Telemetry Delivery System (TDS) Data
Base. Each MON-5-15 file is accompanied by a PDS label with
file name sssttaayyyy_ddd_hhmm_hhmmrr.LBL. Typical file size
is 25 MB. The available MON-5-15 channels, their names,
and definitions are:
MON-5-15 Name Definition
Channel #
M-0037 SC_NUM Spacecraft Code
M-0300 ANT A ID Receiving Antenna 'A' ID
M-0301 ANT A EL VAL Parameter Descriptor Word (PDW)
Validity Field for Receiving
Antenna 'A' Elevation Angles
M-0304 ANT A EL ANG Receiving Antenna 'A' Elevation
Angle in Floating Point Format
in Units of Degrees
M-0308 A CNSCN Receiving Antenna 'A' Conscan Drive
Status
M-0309 A CNSCN LOOP Receiving Antenna 'A' Conscan
Loop Status
M-0340 A A VAL PDW Validity Field for Receiving
Antenna 'A' Receiver 'A'
M-0343 A RCVA LOCK Receiving Antenna 'A' Receiver 'A'
Lock Status
M-0344 A RCVA STAT Receiving Antenna 'A' Receiver 'A'
Status
M-0346 A RCVA BAND Receiving Antenna 'A' Receiver 'A'
Band
M-0349 A RCVA AGC Receiving Antenna 'A' Receiver 'A'
Signal Level Auto Gain Control (AGC)
M-0350 A A PPM VAL Validity Field for Receiving Antenna
'A' Precision Power Monitor (PPM) Data
M-0370 A B VAL PDW Validity Field for Receiving
Antenna 'A' Receiver 'B'
M-0373 A RCVB LOCK Receiving Antenna 'A' Receiver 'B'
Lock Status
M-0374 A RCVB STAT Receiving Antenna 'A' Receiver 'B'
Status
M-0376 A RCVB BAND Receiving Antenna 'A' Receiver 'B'
Band
M-0379 A RCVB AGC Receiving Antenna 'A' Receiver 'B'
Signal Level AGC
M-0380 A B PPM VAL Validity Field for Receiving Antenna
'A' Receiver 'B' PPM Data
M-0215 RTC2 LOCK Real-Time Telemetry Combiner (RTC)
Channel 2 Lock Status
M-0311 A C1 DOP MD Doppler Mode Antenna 'A' Channel 1,
S Band
M-0312 A C1 REQ DOP Requested Doppler Sample Rate Antenna
'A' Channel 1
M-0314 A C2 DOP MD Doppler Mode Antenna 'A' Channel 2,
X Band
M-0315 A C2 REQ DOP Requested Doppler Sample Rate Antenna
'A' Channel 2
M-0500 TXR ANT ID Transmitting Antenna ID
M-0501 L TXR VAL Validity Field for Low-Power
Transmitter Data
M-0504 L PWR TXR ID Transmitter ID
M-0509 L PWR TX PWR Transmitter Power
M-0511 H TXR VAL Validity Field for High-Power
Transmitter Data
M-0524 EXCITER FREQ Exciter Frequency
M-0600 DOP VAL Validity Field for Doppler Data from
the Metric Data Assembly (MDA) Data
M-0612 DOP BIAS X X Band Doppler Bias Frequency
M-0611 DOP NOISE X X Band Doppler Noise
M-0613 NUM SLIP X X Band # Slipped Cycles
M-0614 DOP RES X X Band Doppler Residual
M-0626 DOP CNT X X Band Doppler Count
M-0627 DOP CNT X FR Fractional Part of X Band Doppler
Count
M-0605 RNG VAL Validity Field for Range Data from the
MDA Data
M-0320 APA A VAL Validity Field for Antenna Processing
Assembly (APA) Antenna 'A' Angles
M-0305 ANT A AZ ANG Receiving Antenna 'A' Azimuth Angle
in Double Integer Format in Units
of Degrees
M-0306 ANT A AZ RES Receiving Antenna 'A' Azimuth Angle
Residual
M-0324 ANT A EL ANG Receiving Antenna 'A' Elevation Angle
in Double Integer Format in Units of
Degrees.
M-0307 ANT A EL RES Receiving Antenna 'A' Elevation Angle
Residual
M-0660 SBR MOV Subreflector Moving Message Moving
Flag
M-0663 SBR MOV TIME Time of Latest Subreflector Moving
Message Received for M-0660
M-0670 SBR FIX Subreflector Fixed Message Moving Flag
M-0673 SBR FIX TIME Time of Latest Subreflector Moving
Message Received for M-0670
M-0723 AA5 PCNO Antenna A Receiver A Block V
Receiver (BVR) Channel Signal-to-Noise
Ratio
M-0724 AA5 SNT VAL Antenna A Receiver A BVR Validity
Field for BVR System Noise Temperature
Data
M-0725 AA5 SNT Antenna A Receiver A BVR System
Noise Temperature
M-0739 AA5 LBW Antenna A Receiver A BVR Carrier
Loop Bandwidth
M-0773 AB5 PCNO Antenna A Receiver B Block V
Receiver (BVR) Channel Signal-to-Noise
Ratio
M-0774 AB5 SNT VAL Antenna A Receiver B BVR Validity
Field for BVR System Noise Temperature
Data
M-0775 AB5 SNT Antenna A Receiver B BVR System
Noise Temperature
M-0789 AB5 LBW Antenna A Receiver A BVR Carrier
Loop Bandwidth
M-0616 RNG MOD X X Band Ranging Modulation Indicator
M-0316 ANT A SRC Antenna A Source Code
M-0310 A POL S BD Antenna A Polarization, S-Band
M-0313 A POL X BD Antenna A Polarization, X-Band
Path Delay Files (PD1 and PD2 Directories)
-----------------------------------------------------------
Path Delay files are ASCII files and they are produced by the
RSSG at JPL. File names have the form
sssttaayyyy_ddd_hhmm_hhmmrr.PD1 (stored in the PD1 directory - the
'1' in 'PD1' indicates that the data have been collected from
Advanced Water Vapor Radiometer (AWVR) Unit 1) and
sssttaayyyy_ddd_hhmm_hhmmrr.PD2 (stored in the PD2 directory - the
'2' in 'PD2' indicates that the data have been collected from AWVR
Unit 2) where 'hhmm_hhmm' is the start and end time of the data
and rr is the receiving station. Each Path Delay file
is accompanied by a PDS minimal label with file name
sssttaayyyy_ddd_hhmm_hhmmrr.LBL. Typical file size is 135 KB.
Telemetry Files (TLM Directory)
---------------------------------------------------
Telemetry files are ASCII files with names
sssttaayyyy_ddd_hhmm_hhmm.TLM where 'hhmm_hhmm' is the start and
end time of the file. They are channelized DSN Telemetry Data files
and they are produced at JPL by a Query Server operating on DSN
Telemetry packets stored in the JPL Telemetry Delivery System (TDS)
Data Base. Each Telemetry file is accompanied by a PDS label
with file name sssttaayyyy_ddd_hhmm_hhmm.LBL. Typical file size
is 50 MB. The available Telemetry channels, their names and
definitions are:
Telemetry Name Definition
Channel #
S-0181 KAT_UNLOCK Ka-Band Translator (KAT)
Receiver Lock Latch
S-0182 SBT_STATE_SW S-Band Transmitter (SBT)
On/Off State
(Commanded Mode)
S-0183 KAT_STATE_SW KAT On/Off State
(Commanded Mode)
S-0185 KEX_STATE Ka-Band Exciter (KEX)
On/Off State
S-0186 KAT_STATE_HW KAT Off/On
(Actual Status)
S-0188 KTWT_SBY_HW Ka-Band Traveling Wave
Tube Amplifier (KATWTA)
Standby Enable/Inhibit
(Actual Status)
S-0189 KAT_RCVR_LCK KAT Receiver
Locked/Unlocked
S-0190 SBT_STATE_HW SBT Off/On
(Actual Status)
S-0191 SBT_REF_HW SBT Reference
(Actual Status)
S-0192 SBT_REF_SW SBT Reference
(Commanded Mode)
S-0193 KTWT_SBY_SW KATWTA Standby
Enable/Inhibit
(Commanded Mode)
S-0166 KTWT_P_IN_r KATWTA Input Power Level
(Residual)
S-0164 KTWT_P_OUT_r KATWTA Output Power Level
(Residual)
S-0100 KAT_SPE_a KAT Receiver Static Phase
Error (Telemetry Control
Unit (TCU) A)
S-0102 SBT_P_OUT_a SBT Output Power
Level (TCU A)
S-0104 KEX_P_OUT_a KEX Output Power
Level (TCU A)
S-0106 KEX_X_PWR_a KEX X-Band Power
Level (TCU A)
S-0108 KEX_PCV_a KEX Power Conv
Voltage (TCU A)
S-0112 KTWT_HLX_I_a KATWTA Helix
Current (TCU A)
S-0114 KTWT_P_OUT_a KATWTA Output
Power Level (TCU A)
S-0116 KTWT_P_IN_a KATWTA Input
Power Level (TCU A)
S-0118 KTWT_CTH_I_a KATWTA Cathode
Current (TCU A)
S-0120 KAT_TEMP_a KAT Temperature (TCU A)
S-0122 SBT_TEMP_a SBT Temperature (TCU A)
S-0124 KTWT_TEMP_a KATWTA Temperature (TCU A)
S-0126 KEX_TEMP_a KEX Temperature (TCU A)
S-0128 KTWT_CURR_a KATWTA Prime Current
(TCU A)
C-Kernel Files (CKF Directory)
---------------------------------------------------
C-Kernel Files are in transfer format and they are produced by the
Cassini Attitude and Articulation Control Subsystem team (AACS).
File names have the form sssttaayyyy_ddd_yyyy_ddd.CKF where
'yyyy_ddd_yyyy_ddd is the start and end time of the file. Each
C-Kernel file is accompanied by a PDS minimal label with file name
sssttaayyyy_ddd_yyyy_ddd.LBL. Typical file size is 18 MB.
Earth Orientation Parameter files (EOP Directory)
---------------------------------------------------
Earth Orientation Parameter files are ASCII files and they are
produced by the Kalman Earth Orientation Filter (KEOF) Group
at JPL. File names have the form sssttaayyyy_ddd_yyyy_ddd.EOP.
Each EOP file is accompanied by a PDS minimal label with file
name sssttaayyyy_ddd_yyyy_ddd.LBL. Typical file size is 24 KB.
Ionosphere Calibration Files (ION Directory)
---------------------------------------------------
Ionosphere Calibration files are produced by the Tracking
System Analytic Calibration (TSAC) Group at JPL. They provide
historical and predicted Earth ionospheric conditions.
File names have the form sssttaayyyy_ddd_yyyy_ddd.ION.
Each ION file is accompanied by a PDS minimal label with file
name sssttaayyyy_ddd_yyyy_ddd.LBL. Typical file size is 23 KB.
Spacecraft/Planetary Ephemeris (SP-Kernel) Files (SPK Directory)
----------------------------------------------------------
Spacecraft/Planetary Ephemeris Files (also known as SP kernels
or SPK files) are produced by the Cassini Navigation Team
(NAV). These files give spacecraft and planetary ephemerides.
File names have the form sssttaayyyy_ddd_yyyy_ddd.SPK. One SPK
file has been included, covering GWE2 (file size 27KB).
This SPK file is accompanied by a PDS minimal label with file name
having the form sssttaayyyy_ddd_yyyy_ddd.LBL.
Troposphere Calibration Files (TRO Directory)
---------------------------------------------------
Troposphere Calibration files are produced by the
Tracking System Analytic Calibration (TSAC) Group at JPL.
They provide historical and predicted Earth tropospheric
conditions. File names have the form sssttaayyyy_ddd_yyyy_ddd.TRO.
Each TRO file is accompanied by a PDS minimal label with file name
sssttaayyyy_ddd_yyyy_ddd.LBL. Typical file size is 120 KB.
Files in the CALIB Directory
=============================
The CALIB directory contains a Leapsecond kernel file, a Spacecraft
Clock Conversion file, and a Boresight Calibration Report. All files
in the CALIB directory are ASCII text files with variable length
records delimited by ASCII carriage-return line-feed pairs. All file
names in this directory contain the string 'yymmdd', where yy, mm,
dd indicate the year, month and day of the file creation.
Leapsecond kernel files are a record of leap seconds (past and
predicted) that allow proper conversion between ephemeris time
and UTC. File names are of the form:
LSK_yymmdd.TLS
Each file LSK_yymmdd.TLS is accompanied by a PDS detached minimal
label with name LSK_yymmdd.LBL.
Spacecraft Clock Conversion files allow time measured by the
spacecraft clock to be converted to other time systems (e.g.,
ephemeris time or UTC). File names are of the form:
TSC_yymmdd.SCK
Each file TSC_yymmdd.SCK is accompanied by a PDS detached minimal
label with name TSC_yymmdd.LBL.
The Boresight Calibration Reports are produced by the Radio Science
Systems Group (RSSG) at JPL. The naming convention for these files
is:
BORESIGHT_yymmdd.TXT
Coordinate System
=================
SPK files are produced in the J2000 inertial
reference frame. Other data types are not dependent on any
definition of a coordinate system.
Software
========
Software for parsing, reducing, and analyzing data such as
these has been developed at JPL and elsewhere. Because such
software must usually operate at the bit-level and is written
for a narrow range of platforms, it is unsuitable for
general distribution. As such, no software is included with
this archival data set.
Media/Format
============
The archival data set is written on DVD-R media. The DVD-R volumes
conform to the 'UDF_ISO-9660_BRIDGE' structure as required by PDS.
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