| DATA_SET_DESCRIPTION |
Data Set Overview
================
The Mars Express (MEX) Radio Science (MaRS) Data
Archive is a time-ordered collection of raw and partially
processed data collected during the MEX Mission to Mars.
For more information on the investigations proposed see
the MaRS User Manual [MARSUSERMANUAL2004] in the MaRS
DOCUMENT/MRS_DOC folder.
This is a Occultation measurement covering the time
2006-01-01T08:00:29.500 to 2006-01-01T08:27:09.750.
This data set was collected during the MEX Extended Mission
Phase (EXT1) 2006-2007.
There were three types of scientific measurements conducted
during Extended Mission:
Occultation, Bistatic Radar and Gravity where one has to
distinguish between global gravity measurements which were
conducted around apocenter and target gravity measurements
which were conducted around pericenter over interesting
geophysical structures. For more information see INST.CAT or
the MaRS User Manual [MARSUSERMANUAL2004].
For all measurements if not indicated otherwise Transponder 1
onboard the s/c was used. Transponder 2 is designed to be a
backup.
Mission Phase Definition
========================
It should be noted that the Mars Express (MEX) Radio Science
(MaRS) group uses mission phases which deviate from the ones
defined in the MISSION.CAT files given by ESA in order to keep
the keywords and abbreviations consistent for Mars Express,
and Rosetta. For Venus Express other definitions are used.
Those mission phase abbreviations are also used in the data
description field of the dataset_id.
MaRS mission name | abbreviation | time span
================================================================
Near Earth Verification | NEV | 2003-06-02 - 2003-07-31
----------------------------------------------------------------
Cruise 1 | CR1 | 2003-08-01 - 2003-12-25
----------------------------------------------------------------
Mission Commissioning | MCO | 2003-12-26 - 2004-06-30
----------------------------------------------------------------
Prime Mission | PRM | 2004-07-01 - 2005-12-31
----------------------------------------------------------------
Extended Mission 1 | ENT1 | 2006-01-01 - 2007-10-31
----------------------------------------------------------------
Extended Mission 2 | ENT2 | 2007-11-01 - tbd
Data files
----------
Data files are:
The tracking files from Deep Space Network (DSN) and from
the Intermediate Frequency Modulation System (IFMS) used by
the ESA ground station New Norcia. Level 1A to level 2 data
are archived. The predicted and reconstructed Doppler and
range files Geometry files.
All Level 1A binary data files will have the file name
extension eee = .DAT
IFMS Level 1A ASCII data files will have the file name
extension eee = .RAW
Level 1B and 2 tabulated ASCII data files will have the file
name extension eee = .TAB
Binary data files will have the file name extension .DAT
Data levels
----------
It should be noted that these data levels which are also used
in the file names and data directories are PSA data levels
whereas in the PDS label files CODMAC levels are used.
PSA data level | CODMAC level
-----------------------------
1A | 1
1B | 2
2 | 3
Data Set Identifier
-------------------
The 'DATA_SET_ID' is a unique alphanumeric identifier for
the data sets.
It looks something like:
XXX-Y-ZZZ-U-VVV-NNNN-WWW
Acronym | Description | Example
--------------------------------------------------------
XXX | Instrument Host ID | MEX
--------------------------------------------------------
Y | Target ID | M (for Mars) or X for
| | other like for example
| | for sun during solar
| | conjunction measurements
--------------------------------------------------------
ZZZ | Instrument ID | MRS
--------------------------------------------------------
U | Data level (here | 1/2/3 (Data set
| CODMAC levels are used) | contains raw, edited
| | and calibrated data)
---------------------------------------------------------
VVV | MaRS mission phase |MCO
| (deviate from the |(for values see above)
| mission phases) |
---------------------------------------------------------
NNNN | 4 digit sequence number | 0123
| which is identical to |
| the Radio Science |
| Volume_id |
---------------------------------------------------------
WWW | Version number | V1.0
MaRS data were originally archived as volumes rather than data
sets. However, ESA PSA does not uses volume but data set.
To avoid confusion it was specified that one MaRS data volume
is equal one data set. Thus the data set was also assigned a 4
digit sequence number which is identical to the one used in
the volume_id. If the data_set_id is known it is automatically
specified on which volume the data set is found.
VOLUME_ID
---------
The VOLUME_ID is a unique alphanumeric identifier for volume.
The Volume ID provides a unique identifier for a single MaRS,
RSI or VeRa data volume, typically a physical CD-ROM or DVD.
The volume ID is also called 'volume label' by the various CD-
ROM recording software packages. The Volume ID is formed using
a mission identifier, an instrument identifier of 3 charac-
ters, followed by an underscore character, followed by a 4
digit sequence number. In the 4-digit number, the first one
represents the volume set, the remaining digits define the
range of volumes in the volume set. For Mars Express the first
digit is not defined after the kind of measurement (see below
for Rosetta and VEX), but after the Mission phase.
0000: Commissioning
1000: Occultation
2000: Gravity
3000: Solar Conjunction
4000: Bistatic Radar
5000: Passive/Active Checkouts
6000: Swing-bys/Fly-bys
7000: Cometary Coma Observations
It looks something like:
XXXXXX-ZZZZ
Acronym | Description | Example
--------------------------------------------------------
XXXXXX | Mission and Instrument ID | MEXMRS
--------------------------------------------------------
ZZZZ | 4 digit sequence number | 0123
Important note: the here defined ESA PSA Volume_Id is not identical
with the Radio Science Volume_Id. The Radio Science Volume_Id is a
number which is incremented measurement by measurement, independent
what kind of measurement was conducted. The Radio Science Volume_Id
belonging to one single measurement can be find in the Logbook, loca-
ted in the folder DOCUMENT/MRS_DOC.
Descriptive files
-----------------
Descriptive files contain information in order to support
the processing and analysis of data files. The following
file types are defined as descriptive files with extension
eee =
.LBL PDS label files
.CFG IFMS configuration
.AUX Ancillary files (event files, attitude files,
ESOC orbit files, products, SPICE files)
.TXT Information (text) files
File naming convention
======================
All incoming data files will be renamed and all processed data
files will be named after the following file naming convention
format. The original file name of the incoming tracking data
files will be stored in the according label file as
source_product_id.
The new PDS compliant file name will be the following:
rggttttlll_sss_yydddhhmm_qq.eee
Acronym | Description | Examples
=============================================================
r | space craft name abbreviation | M
| R = Rosetta |
| M = Mars Express |
| V = Venus Express |
-------------------------------------------------------------
gg | Ground station ID: | 43
| |
| 00: valid for all ground stations; |
| various ground stations or independent |
| of ground station or not feasible to |
| appoint to a specific ground station or |
| complex |
| |
| DSN complex Canberra: |
| --------------------- |
| 34 = 34 m BWG (beam waveguide) |
| 40 = complex |
| 43 = 70 m |
| 45 = 34 m HEF (high efficiency) |
| |
| ESA Cebreros antenna: |
| --------------------- |
| 62 = 35 m |
| |
| DSN complex Goldstone: |
| ---------------------- |
| 10 = complex |
| 14 = 70 m |
| 15 = 34 m HEF |
| 24 = 34 m BWG |
| 25 = 34 m BWG |
| 26 = 34 m BWG |
| 27 = 34 m HSBWG |
| |
| ESA Kourou antenna: |
| ------------------- |
| 75 = 15 m |
| |
| DSN complex Madrid: |
| ------------------- |
| 54 = 34 m BWG |
| 55 = 34 m BWG |
| 63 = 70 m |
| 65 = 34 m HEF |
| 60 = complex |
| |
| ESA New Norcia antenna: |
| ----------------------- |
| 32 = 35 m |
-------------------------------------------------------------
tttt | data source identifier: | TNF0
| |
| Level 1A and 1B: |
| ---------------- |
| ODF0 = ODF closed loop |
| TNF0 = TNF closed loop (L1A) |
| T000-T017 = TNF closed loop (L1B) |
| ICL1 = IFMS 1 closed loop |
| ICL2 = IFMS 2 closed loop |
| ICL3 = IFMS RS closed loop |
| IOL3 = IFMS RS open loop |
| R1Az = RSR block 1A open loop |
| R1Bz = RSR block 1B open loop |
| R2Az = RSR block 2A open loop |
| R2Bz = RSR block 2B open loop |
| R3Az = RSR block 3A open loop |
| R3Bz = RSR block 3B open loop |
| z=1...4 subchannel number |
| ESOC = ancillary files from ESOC DDS |
| DSN0 = ancillary files from DSN |
| SUE0= ancillary and information files |
| coming from Stanford University |
| center for radar astronomy |
| |
| Level 2: |
| ------- |
| UNBW = predicted and reconstructed |
| Doppler and range files |
| ICL1 = IFMS 1 closed loop |
| ICL2 = IFMS 2 closed-loop |
| ICL3 = IFMS RS closed-loop |
| ODF0 = DSN ODF closed loop file |
| T000-T017 = TNF closed loop file |
| RSR0 = DSN RSR open loop file |
| RSRC = DSN RSR open loop file containing |
| data with right circular |
| polarization (only solar |
| conjunction measurement) |
| RSRL = DSN RSR open loop file containing |
| data with left circular |
| polarization (only solar |
| conjunction measurement) |
| NAIF = JPL or ESTEC SPICE Kernels |
| SUE0 = ancillary information and |
| calibration files coming from |
| Stanford University center for |
| radar astronomy |
| GEOM = geometry file |
| |
--------|------------------------------------------|--------
lll | Data archiving level | L1A
| L1A = Level 1A |
| L1B = Level 1B |
| L02 = Level 2 |
| L03 = Level 3 |
--------|------------------------------------------|--------
sss | data type |
| |
| IFMS data files level 1A: |
| ------------------------- |
| D1X uncalibrated Doppler 1 X-Band |
| D1S uncalibrated Doppler 1 S-Band |
| D2X uncalibrated Doppler 2 X-Band |
| D2S uncalibrated Doppler 2 S-Band |
| C1X Doppler 1 X-Band equip. calibration |
| C1S Doppler 1 S-Band equip. calibration |
| C2X Doppler 2 X-Band equip. calibration |
| C2S Doppler 2 S-Band equip. calibration |
| RGX uncalibrated X-Band range |
| RGS uncalibrated S-Band range |
| MET meteo file |
| AG1 AGC 1 files |
| AG2 AGC 2 files |
| RCX X-Band range equip. calibration |
| RCS S-Band range equip. calibration |
| |
| DSN data files level 1A: |
| ------------------------- |
| ODF original orbit files (closed loop) |
| RSR radio science receiver open-loop file|
| TNF file (closed loop) |
| |
| ESOC ancillary data level 1A: |
| ----------------------------- |
| ATR attitude file, reconstructed |
| EVT orbit event file |
| OHC orbit file, heliocentric cruise |
| OMO orbit file, marscentric, operational |
| |
| DSN Calibration files level 1A: |
| ------------------------------- |
| TRO DSN tropospheric calibration model |
| MET DSN meteorological file |
| ION DSN ionospheric calibration model |
| BCL SUE Bistatic radar temperature |
| calibration |
| |
| DSN ancillary data level 1A: |
| ----------------------------- |
| DKF DSN Keyword File |
| MON DSN monitor data |
| NMC DSN Network Monitor and Control file |
| SOE DSN Sequence of Events |
| EOP DSN earth orientation parameter file |
| ENB SUE Experimenter Notebook |
| MFT SUE Manifest files |
| LIT DSN Light time file |
| HEA DSN Data collection list |
| OPT DSN Orbit and timing geometry file |
| |
| DSN Browse Plots level 1A: |
| -------------------------- |
| BRO bistatic radar 4-panel plots (browse)|
| |
| IFMS data files level 1B: |
| ------------------------- |
| D1X uncalibrated Doppler 1 X-band |
| D1S uncalibrated Doppler 1 S-band |
| D2X uncalibrated Doppler 2 X-band |
| D2S uncalibrated Doppler 2 S-band |
| C1X Doppler 1 X-band equip. calibration |
| C1S Doppler 1 S-band equip. calibration |
| C2X Doppler 2 X-band equip. calibration |
| C2S Doppler 2 S-band equip. calibration |
| RGX uncalibrated X-band range |
| RGS uncalibrated S-band range |
| MET meteo |
| AG1 AGC 1 |
| AG2 AGC 2 |
| RCX X-band range equip. calibration |
| RCS S-band range equip. calibration |
| |
| DSN ODF data files level 1B: |
| ----------------------------- |
| DPS S-band Doppler |
| DPX X-band Doppler |
| RGS uncalibrated S-Band ranging file |
| RGX uncalibrated X-Band ranging file |
| RMP uplink frequency ramp rate file |
| |
| DSN calibration data level 1B: |
| ----------------------------- |
| MET meteorological file |
| |
| IFMS data level 2: |
| ----------------- |
| D1X uncalibrated Doppler 1 X-Band |
| D1S uncalibrated Doppler 1 S-Band |
| D2X uncalibrated Doppler 2 X-Band |
| D2S uncalibrated Doppler 2 S-Band |
| RGX uncalibrated X-Band range |
| RGS uncalibrated S-Band range |
| RCX X-Band range equip. calibration |
| RCS S-Band range equip. calibration |
| |
| IFMS Browse plots level 2 |
| ------------------------- |
| B1X Quick look plots of calibrated |
| Doppler 1 X-band |
| B1S Quick look plots of calibrated |
| Doppler 1 S-band |
| B2X Quick look plots of calibrated |
| Doppler 2 X-band |
| B2S Quick look plots of calibrated |
| Doppler 2 S-band |
| |
| DSN level 2 data: |
| ----------------- |
| DPX calibrated Doppler X-band |
| DPS calibrated Doppler S-band |
| RGS calibrated S-band ranging file |
| RGX calibrated X-band ranging file |
| BSR bistatic radar power spectra |
| SRG bistatic radar surface reflection |
| geometry file |
| |
| DSN level 2 calibration data: |
| ---------------------------- |
| SRF Surface Reflection Filter Files |
| |
| orbit files level 2: |
| -------------------- |
| PTW Doppler & range prediction two-way |
| PON Doppler & range prediction on |
| RTW reconstructed Doppler & range orbit |
| file two-way |
| RON reconstructed Doppler & range orbit |
| file one-way |
| LOC heliocentric state vector file |
| |
| Constellation file Level 2: |
| --------------------------- |
| MAR Mars constellation file |
| VEN Venus constellation file |
| P67 Churyumov-Gerasimenko |
| constellation file |
| |
| SPICE kernel files level 2: |
| --------------------------- |
| BSP binary spacecraft/location |
| kernel file |
| FRM frame kernel file |
| ORB orbit numbering file |
| PBC predicted attitude kernel file |
| PCK planetary constant kernel |
| SCK space craft clock kernel |
| TLS leap second kernel file |
| |
| Science data level 3: |
| --------------------- |
| SCP solar corona science |
--------|------------------------------------------|--------
yy | Year | 04
--------|------------------------------------------|--------
ddd | Day of year | 153
--------|------------------------------------------|--------
hhmm | Sample hour, minute start time | 1135
| For IFMS files this is the ESOC |
| reference time tag which usually |
| coincides with the first sample time. |
| For IFMS Ranging files however this is |
| not true. Here the reference time tag |
| is two-way light time before the first |
| actual measurement. |
--------|------------------------------------------|--------
qq | Sequence or version number | 01
--------|------------------------------------------|--------
eee | .DAT binary files (Level 1A) | .RAW
| .TAB ASCII table data file |
| .AUX ancillary file |
| .CFG IFMS configuration file (Level 1B) |
| .LBL PDS label files |
| .TXT information files |
| .RAW ASCII data files (Level 1A) |
| .LOG Processing log files (Level 2) |
Processing (DSN)
================
TNF's are screened for 'bad' data points by the JPL Radio Metric
Data Conditioning Team (RMDCT) before the files are processed to
ODF's. The TNF's included in this archive, however, are the pre-
screened versions.
The open-loop (RSR) data in the archive have been assembled from
individual records (packets) into files. They have not
otherwise been processed.
The Level 2 radio occultation data have been processed as
follows.
The RSR samples were digitally filtered to reduce bandwidth;
in the process they were also converted from 16-bit I and
16-bit Q complex integer samples to 64-bit I and 64-bit Q
double precision complex floating point samples. The complex
floating point samples were Fourier transformed and estimates
made of the carrier amplitude and frequency and their uncer-
tainties.
The reconstructed spacecraft trajectory, planetary epheme-
rides, records of uplink and downlink tuning, and other data
were used to calculate the expected carrier frequency at the
receiving antenna.
The Level 2 products are tables of the observed amplitude, its
uncertainty, the observed frequency, its uncertainty, and the
difference between the observed and the expected frequency as
a function of time. Separate tables have been created for
each RSR.
The Level 2 bistatic radar spectra (SPC) have been processed as
follows.
The RSR samples were converted from 16-bit I and 16-bit Q
complex integer samples to 64-bit I and 64-bit Q double
precision complex floating point samples. In the process they
were digitally corrected for non-uniform spectral response of
the receiving system. This was done by computing spectra from
series of time samples and dividing each spectrum by the
square root of a power spectrum computed from many minutes of
noise. The amplitude of the samples was then adjusted so that
power spectra in each receiver channel would have an amplitude
proportional to kTsysB where k is Boltzmann's constant, Tsys
is the receiver system temperature in Kelvin, and B is the
width of one frequency bin (spectral resolution) in the power
spectrum.
Then the power spectra (e.g., XR*conj(XR)) and cross spectra
(e.g., XR*conj(XL)) were computed.
Structure of DATA Directory
===========================
Please note that the following description lists all possible
subfolders. If however there is no data to fill some of these
folders they will not be generated.
|-DATA
| |-LEVEL1A
| | |-CLOSED_LOOP
| | | |-DSN
| | | | |-ODF Orbit Data Files
| | | | |-Tracking and Navigation Files
| | | |
| | | |-IFMS
| | | |-AG1 Auto Gain Control 1 data files
| | | |-AG2 Auto Gain Control 2 data files
| | | |-DP1 Doppler 1 data files
| | | |-DP2 Doppler 2 data files
| | | |-RNG Ranging data files
| | |
| | |-OPEN_LOOP
| | | |-DSN
| | | | |-RSR Radio-Science Receiver data files
| | | |
| | |-IFMS
| | |-AG1 Auto Gain Control 1 data files
| | |-AG2 Auto Gain Control 2 data files
| | |-DP1 Doppler 1 data files
| | |-DP2 Doppler 2 data files
| | |-RNG Ranging data files
| |
| |-LEVEL1B
| | |-CLOSED_LOOP
| | | |-DSN
| | | | |-ODF Orbit Data Files
| | | |
| | | |- IFMS
| | | | |- AG1 Auto Gain Control 1 data files
| | | | |- AG2 Auto Gain Control 2 data files
| | | | |- DP1 Doppler 1 data files
| | | | |- DP2 Doppler 2 data files
| | | | |- RNG Ranging data files
| | |
| | |- OPEN_LOOP
| | | |-IFMS
| | | | |-AG1 Auto Gain Control 1 data files
| | | | |-AG2 Auto Gain Control 2 data files
| | | | |-DP1 Doppler 1 data files
| | | | |-DP2 Doppler 2 data files
| | | | |-RNG Ranging data files
| |
| |-LEVEL2
| | |- CLOSED_LOOP
| | | |- DSN
| | | | |-ODF Orbit Data Files
| | | |
| | | |- IFMS
| | | | |-DP1 Doppler 1 data files
| | | | |-DP2 Doppler 2 data files
| | | | |-RNG Ranging data files
| | |
| | |- OPEN_LOOP
| | | |-DSN
| | | | |-BSR Bistatic radar power spectra
| | | | |-SRG Bistatic radar surface reflection
| | | | | geometry file
| | | | |-DPX Doppler X-Band files
| | | | |-DPS Doppler S-Band files
| | | |
| | | |-IFMS
| | | | |-DP1 Doppler 1 data files
| | | | |-DP2 Doppler 2 data files
| | | | |-RNG Ranging data files
Files in the DATA Directory
---------------------------
Files in the DATA directory are:
Data Level 1A:
--------------
Level 1A data are incoming raw tracking data files obtained
either from ESA IFMS or DSN. All incoming data files will be
renamed after the file naming convention format defined in
section 5.1 of the MaRS File Naming Convention document
[MARSFNC2004] and get a minimal detached label file .LBL. The
original file name of the incoming tracking data files will be
stored in the according label file as SOURCE_PRODUCT_ID. These
files have the file extension .RAW if ASCII and .DAT if binary
files.
TNF's are screened for 'bad' data points by the JPL Radio Metric
Data Conditioning Team (RMDCT) before the files are processed to
ODF's. The TNF's included in this archive, however, are the pre-
screened versions.
Tracking and Navigation Files (TNF Directory)
---------------------------------------------
TNF's became available within a few hours of the completion of
a Mars Express pass.
Orbit Data Files
----------------
ODF's were typically issued daily throughout the MEX mission
with weekend data being consolidated into a single file on
Monday. Typical ODF's have sizes 15-50 kB.
All ODFs in the NEV archive have 60 second sampling. For
higher sampling rates, the user must resort to the (more
primitive) TNF products.
Radio Science Receiver Files (RSR Directory)
--------------------------------------------
Each RSR generated a stream of packets which could be
assembled into files of arbitrary length. It was decided,
after some experimentation, that files containing about 300 MB
were the largest that could be easily manipulated in the
analysis computers available in 2003. With a small number of
exceptions, this is the largest file size that will be found
in the RSR directory.
The open-loop (RSR) data in the archive have been assembled from
individual records (packets) into files. They have not other-
wise been processed.
IFMS Data Level 1B:
-------------------
Level 1B files are processed from level 1A (raw tracking data)
into an edited ASCII formatted file.
Three files are generated for each ESA IFMS Level 1A data file:
Level 1B IFMS data file (extension .TAB)
Level 1B IFMS configuration file (extension .CFG)
Level 1B IFMS label file (extension .LBL)
The label file contains the description of the .TAB as well as
of the .CFG file.
Up to eight files are generated for each DSN ODF Level 1A file:
Level 1B ODF Doppler S-Band data file + label file
Level 1B ODF Doppler X-Band data file + label file
Level 1B ODF Ranging S-Band data file + label file
Level 1B ODF Ranging X-Band data file + label file
Cologne is processing IFMS and ODF data, Stanford University
processes RSR data up to level 2 and forwards raw and processed
data to Cologne for archiving. However, for RSR there will be no
level 1B files.
Data Level 2:
-------------
Level 2 data are calibrated data after further processing. The
file format is in ASCII. This data level can be used for further
scientific interpretation. The keyword OBSERVATION_TYPE in the
Level 2 data labels indicates which kind of measurement was
done. Keyword values are: Occultation, Target Gravity, Global
Gravity, Solar Conjunction, Bistatic Radar, Commissioning and
Phobos Gravity. Commissioning covers the NEV, CR1 and partly MCO
Mission Phase where no specific measurement was done but equip-
ment on board the spacecraft and on ground station was tested.
IFMS Level 2 input files:
-------------------------
There may be several Doppler 1 X-Band files in level 1A
which will be merged on level 2. The same is true for all
other Doppler file type and Ranging X and S-Band files.
Only files with continuous sequenced numbers (the file
names are the same only the sequence number varies for
these files) are merged together. Otherwise a new Level
02 data file is created (merging data files with a new
sequence of files).
The level 2 source_product_id however gives the RAW IFMS
file names since the raw files are used for processing.
But the content of the IFMS raw files are identical to the
corresponding level 1A IFMS files in one data set, only
the file name is different. And the source_product_id of
the level 1A files gives the original raw IFMS files. In
addition the level 1A files have almost the same file name
as the corresponding level 2 files.
The corresponding level 1A files can be found in
DATA/LEVEL1A/CLOSED_LOOP/IFMS/DP1 for Doppler 1 files
DATA/LEVEL1A/CLOSED_LOOP/IFMS/DP2 for Doppler 2 files
DATA/LEVEL1A/CLOSED_LOOP/IFMS/RNG for Ranging files
----------------------------------------------------------
Example:
M32ICL1L02_D1X_040931103_00.TAB
is a level 2 Doppler 1 X-Band file
in M32ICL1L02_D1X_040931103_00.LBL
the following SOURCE_PRODUCT_ID is given:
SOURCE_PRODUCT_ID = {NN11_MEX1_2004_093_OP_D1_110358_0000,
NN11_MEX1_2004_093_OP_D1_110358_0001,
NN11_MEX1_2004_093_OP_D1_110358_0002}
which are the raw IFMS files.
The corresponding Level 1A files can be found in
DATA/LEVEL1A/CLOSED_LOOP/IFMS/DP1
Their names are:
M32ICL1L1A_D1X_040931103_00.RAW
M32ICL1L1A_D1X_040931103_01.RAW
M32ICL1L1A_D1X_040931103_02.RAW
and the corresponding label files give the
source_product_id as:
in the M32ICL1L1A_D1X_040931103_00.LBL file the
source_product_id is given as:
SOURCE_PRODUCT_ID = NN11_MEX1_2004_093_OP_D1_110358_0000
in the M32ICL1L1A_D1X_040931103_01.LBL file the
source_product_id is given as:
SOURCE_PRODUCT_ID = NN11_MEX1_2004_093_OP_D1_110358_0001
in the M32ICL1L1A_D1X_040931103_02.LBL file the
source_product_id is given as:
SOURCE_PRODUCT_ID = NN11_MEX1_2004_093_OP_D1_110358_0002
Note that in this example the three level 1A files were
merged to one level 2 files.
The file names of the level 1A files are almost identical
to the level 2 file name with three differences:
- L1A instead of L02 in the file name which tells the user
that these are level 1A and level 2 files.
- The two digit-sequence number at the end of the file can
be different.
- The level 1A files have file extension .RAW whereas
level 2 files have file extension .TAB
----------------------------------------------------------
Other inputs for Doppler and Ranging files:
-------------------------------------------
predicted orbit file (see EXTRAS/ANCILLARY/UNI_BW)
Meteorological file (see CALIB/CLOSED_LOOP/IFMS/MET)
AGC file (see DATA/1A or 1B/CLOSED_LOOP/AGC1 or AGC2)
Spacecraft orbit SPICE kernels (see EXTRAS/ANCILLARY/SPICE
can also be downloaded from
ftp://ssols01.esac.esa.int/pub/data/SPICE/MEX/kernels)
Calibration Documentation:
--------------------------
For documentation about Doppler and Ranging Calibration
please see in DOCUMENT/MRS_DOC/MEX_MRS_IGM_DS_3035 and
MEX_MRS_IGM_DS_3036
For differential Doppler:
-------------------------
If the processed level 2 file is for example Doppler 1
X-Band then information from IFMS raw Doppler 1 S-Band
files which cover approximately the same time were used
for processing as well.
For Doppler 1 S-Band information from IFMS raw Doppler 1
X-Band files were used.
Doppler 2 files were processed accordingly.
In most cases on IFMS1 and IFMS2 X-Band data were
recorded:
The corresponding raw files' names start with NN11_ or
NN12_. S-Band data were in most cases recorded at IFMS3.
The corresponding raw files' names start with NN13_.
If for some reason this configuration was changed this is
indicated either at the beginning of this description or
at the end in the anomaly report.
For Ranging in addition are used:
---------------------------------
Range calibration file (see CALIB/CLOSED_LOOP/IFMS/RCL)
Klobuchar coefficients for Earth-Ionosphere calibration
(can be downloaded from this site:
http://www.aiub.unibe.ch/download/CODE/)
The calibrated Doppler files contain observed IFMS sky
frequency,
X-band Doppler and S-band Doppler frequency shift,
residual (computed using the predict file), and the
differential Doppler.
If only a single downlink frequency was used, a differen-
tial Doppler cannot be computed and was set to -999.999999
in the output file.
The level 2 ranging files contain the observed TWLT at
X-band or S-band, the calibrated TWLT at X-band or S-band,
the TWLT delay at X-band or S-band and the differential
TWLT. If only one frequency was used, the differential
TWLT is set to -99999.9.
IFMS Level 2 output files:
--------------------------
Level 2 IFMS data file (extension .TAB)
Level 2 IFMS label file (extension .LBL)
Level 2 IFMS log file (extension .LOG).
The log files can be found in
/EXTRAS/ANCILLARY/MRS/LOGFILES and contain information
about the level 2 Doppler and Ranging data processing.
ODF Level 2 input files:
------------------------
ODF Level 1B files
Doppler and Range prediction file
or
Orbit reconstructed file
Media calibration files
The calibrated Doppler files contain observed IFMS Doppler
expressed as X-band Doppler or S-band Doppler, residual
and detrended X-band or S-band Doppler (computed using the
predict file), the detrended differential Doppler. If only
one single frequency was used, the differential Doppler
will be set to -999.999999.
The level 2 ranging file contains the observed Two-Way-
Light-Time (TWLT) at X-band or S-band, the calibrated TWLT
at X-band or S-band, the TWLT delay at X-band or S-band
and the differential TWLT. If only one frequency was used,
the differential TWLT is set to -99999.9.
Other inputs for Doppler and Ranging files:
-------------------------------------------
Predicted orbit file (see EXTRAS/ANCILLARY/UNI_BW)
Meteorological file (see CALIB/CLOSED_LOOP/ODF/MET)
Spacecraft orbit SPICE kernels (see EXTRAS/ANCILLARY/SPICE
can also be downloaded from:
ftp://ssols01.esac.esa.int/pub/data/SPICE/MEX/kernels)
RSR Level 2 data:
-----------------
There are four types of 'calibrated' data in the data set;
each is described briefly below.
Surface Reflection Filter Files
-------------------------------
SRF files contain power spectra derived from noise measure-
ments when the radio system was stable and there were no
spacecraft signals in the passband. SRF's were derived sepa-
rately for each receiver channel; but the fact that the
spectral characteristics of each receiver depended almost
entirely on digital signal processing meant that there was
little practical difference among channels when sampling
rates (output bandwidths) were the same and the SRF's were
interchangeable. SRF's were ASCII PDS SPECTRUM objects with
attached labels.
Level 2 Neutral Atmosphere Files
--------------------------------
L2N files were the calibrated output of partial processing of
RSR data collected for radio occultations. They were ASCII
tables of frequencies and amplitudes in physically meaningful
units. Separate L2N files were derived for each receiver
channel. The Level 2 radio occultation data have been
processed as follows:
The RSR samples were digitally filtered to reduce bandwidth;
in the process they were also converted from 16-bit I and
16-bit Q complex integer samples to 64-bit I and 64-bit Q
double precision complex floating point samples. The complex
floating point samples were Fourier transformed and estimates
made of the carrier amplitude and frequency and their
uncertainties.
The reconstructed spacecraft trajectory, planetary epheme-
rides, records of uplink and downlink tuning, and other data
were used to calculate the expected carrier frequency at the
receiving antenna.
The Level 2 products are tables of the observed amplitude, its
uncertainty, the observed frequency, its uncertainty, and the
difference between the observed and the expected frequency as
a function of time. Separate tables have been created for
each RSR.
Level 2 Bistatic Radar Spectra
------------------------------
SPC files were the calibrated output of partial processing of
RSR data collected for bistatic radar. They were ASCII tables
of power and cross-voltage spectra. All spectra for a single
observation were collected in a single ASCII file.
The Level 2 bistatic radar spectra (BSR) have been processed
as follows:
The RSR samples were converted from 16-bit I and 16-bit Q
complex integer samples to 64-bit I and 64-bit Q double
precision complex floating point samples. In the process they
were digitally corrected for non-uniform spectral response of
the receiving system. This was done by computing spectra from
series of time samples and dividing each spectrum by the
square root of a power spectrum computed from many minutes of
noise. The amplitude of the samples was then adjusted so that
power spectra in each receiver channel would have an amplitude
proportional to kTsysB where k is Boltzmann's constant, Tsys
is the receiver system temperature in Kelvin, and B is the
width of one frequency bin (spectral resolution) in the power
spectrum.
Then the power spectra (e.g., XR*conj(XR)) and cross spectra
(e.g., XR*conj(XL)) were computed.
Structure of CALIB Directory
============================
Please note that the following description lists all possible
subfolders. If however there is no data to fill some of these
folders they will not be generated.
|-CALIB
| |-CALINFO.TXT text description of the directory contents
| |
| |-CLOSED_LOOP
| | |-DSN Closed-loop calibration data of the DSN ground
| | | stations
| | |-IFMS
| | | |-RCL Range Calibration data files
| | | |-DCL Doppler Calibration data files
| | | |-MET Meteo data files
| |
| |-OPEN_LOOP
| | |-DSN
| | | |-BCAL System temperature calibration files
| | | |-ION Ionospheric Calibration files
| | | |-MET Meteo data files
| | | |-TRO Tropospheric Calibration files
| | | |-SRF Surface Reflection Filter Files
| | |
| | |-IFMS
| | | |-RCL Range Calibration data files
| | | |-DCL Doppler Calibration data files
| | | |-MET Meteo data files
| |
| |-UPLINK_FREQ_CORRECT Folder includes files which indicate
wrong and corrected uplink frequency
and their corresponding files.
Files in the CALIB Directory
----------------------------
Files in the CALIB directory are:
Calibration data files have in principle the same structure as
normal data files. But they do not contain scientific data but
rather reflect the behaviour of the system. These kind of data
is typically recorded at New Norcia once for every tracking
before the real measurement took place. For example: range
calibration data contain the equipment propagation delay
measurements before the tracking pass.
Note: If the uplink frequency in one of the .RAW files was
identified as wrong the folder UPLINK_FREQ_CORRECT will be
generated. It tells the user which files were affected and where
to find the corrected Level 2 data files.
Closed loop IFMS Calib data level 1A:
-------------------------------------
These Level 1A data are incoming raw tracking data files
obtained from ESA IFMS. All incoming data files will be renamed
after the file naming convention format defined in section 5.1
of the MaRS File Naming Convention document [MARSFNC2004] and
get a minimal detached label file .LBL. The original file name
of the incoming tracking data files will be stored in the
according label file as SOURCE_PRODUCT_ID. These files have the
file extension .RAW.
Closed loop IFMS Calib data level 1B:
-------------------------------------
IFMS Calib level 1B files are processed from level 1A (raw
tracking data) into an edited ASCII formatted file.
Three files are generated for each ESA IFMS Level 1A data file:
Level 1B IFMS data file (extension .TAB)
Level 1B IFMS configuration file (extension .CFG)
Level 1B IFMS label file (extension .LBL)
The label file contains the description of the .TAB as well as
of the .CFG file.
DSN METEO Files (MET directory)
-------------------------------
DSN METEO files were produced by the Tracking System
Analytic Calibration (TSAC) Group at JPL. Files give weather
calibration information for DSN complexes. These are ASCII
files of variable length records. Each record is delimited
by an ASCII line-feed (ASCII 10). METEO files were
typically released weekly and contain all weather data for the
complex since 1 January. Each METEO file is accompanied by a
PDS label. The files grow at the rate of approximately 90 kB
per month.
DSN Ionosphere Calibration Files (ION Directory)
------------------------------------------------
Ionosphere Calibration files were produced by the Tracking
System Analytic Calibration (TSAC) Group at JPL. They docu-
mented and predicted Earth ionospheric conditions. Global
Ionosphere Map (GIM) software created daily maps from Global
Positioning System (GPS) data. Each day, a final map was
created for the UT day three days previously and a preliminary
map was created for the UT day immediately before.
Also created were predict maps a couple times a week by
averaging recent 'normal' days. Then the software evaluated the
maps at the spacecraft line-of-sight and fitted the results to
a normalized polynomial versus time over each spacecraft pass.
This was done for all three modes: final, preliminary, and
predict. Then the software selected the best available cali-
bration for each pass (in priority order final > preliminary >
predict). An operator ran a plotting program to view all of
the calibrations and overrode the default selections where
desired. The mapping technique is described by
[MANNUCCIETAL1998].
They are ASCII files of variable length records. Each record is
delimited by an ASCII carriage-return line-feed pair
(ASCII 13 followed by ASCII 10). ION files were usually
released at one week intervals to cover a single month; only
final files covering a full month are included in this archive.
Each ION file is accompanied by a PDS minimal label. Typical
file sizes are approximately 50 kB.
Troposphere Calibration Files (TRO Directory)
---------------------------------------------
Troposphere Calibration files were produced by the Tracking
System Analytic Calibration (TSAC) Group at JPL. They docu-
mented and predicted Earth tropospheric conditions and were
based on measurements made using Global Positioning System
(GPS) satellites. These are ASCII files of variable length
records. Each record is delimited by an ASCII line-feed
(ASCII 10).
Surface Reflection Filter Files (SRF Directory)
-----------------------------------------------
SRF files contain power spectra derived from noise measure-
ments when the radio system was stable and there were no
spacecraft signals in the passband. SRF's were derived sepa-
rately for each receiver channel; but the fact that the
spectral characteristics of each receiver depended almost
entirely on digital signal processing meant that there was
little practical difference among channels when sampling rates
(output bandwidths) were the same and the SRF's were inter-
changeable. SRF's were ASCII PDS SPECTRUM objects with
attached labels.
System Temperature Calibration Files (BCAL directory)
-----------------------------------------------------
This table contains system temperature calibration results
from Mars Express (MEX) bistatic radar experiments. For each
receiver channel the table includes the best estimate of
system temperature with the antenna pointed to zenith (either
pre- or post-cal, or a combination of both), the associated
noise diode temperature, and the system temperature at the
mid-point of the bistatic (surface) observation.
In general there is one set of four rows for each experiment -
one for each receiver channel (X-band and S-band, right- and
left-circular polarization). The table is cumulative, growing
by four rows for each new observation. The Bistatic Radar
Calibration Log is produced by the Stanford University Element
(SUE) of the Mars Express Radio Science Team under the
direction of R.A. Simpson.
Browse Files (BROWSE Directory)
===============================
Browse files may be composite PostScript files summarizing
quick-look processing of raw RSR data. In that case each file
has a name: rggttttL1A_BRO_yydddhhmm_00.AUX. Each file has a
JPEG version with the same file name but extension .LBL. Both
files are accompanied by a single detached label of the same
file name but extension .LBL. Each PostScript file is sized to
fit on a single 8-1/2x11 inch page. Each landscape format page
includes four panels showing a histogram of raw data (12-bit)
samples (upper left), one-minute average power spectra derived
from the raw samples (upper right), one-second averages of raw
sample power versus time (lower left), and an extract of the
first few lines of the source RSR PDS label (lower right).
BRO files may be helpful in quickly scanning data to determine
which files are suitable for closer study.
IFMS Browse plot files are only available as JPEG files.
These plots are generated in order to check data quality of
IFMS Level 2 closed-loop data. The name of the files are the
same like the Level 2 data files except for the data type
identifier which is set as sss=B1X,B1S,B2X,B2S if the source
of the plots is a Doppler 1 X-Band, Doppler 1 S-Band, Doppler
2 X-Band or Doppler 2 S-Band file, and the extension will be
.JPG.
Ancillary Data
==============
An extensive set of ancillary files is needed for proper
analysis and interpretation of the radio data. These are
organized in parallel directories and stored approximately
chronologically. When a file type is not represented on a CD-
volume, the corresponding directory has been omitted.
Files in the EXTRAS/ANCILLARY Directory
---------------------------------------
Files in the EXTRAS/ANCILLARY directory are:
ESOC: Relevant DDS files to describe the observation geometry
SPICE: Relevant SPICE Kernels to describe the observation geo-
metry
UNI_BW: Relevant PREDICT files from the Uni BW Munich
MRS: Level 2 processing log files
SUE: Ancillary files coming from Stanford University
|-SPICE:
Spice Kernels were produced by the MEX Flight Dynamics
Team, converted to IEEE binary format, and then distri-
buted 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 ephemeredes 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 rota-
| tion (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 predic-
| tion 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.
|
|-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 compo-
| nents 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.
|
|-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.
Software
========
Software for parsing, reducing, and analyzing data such as
these has been developed at University of Cologne and Stanford
University.
Because such software must usually operate at the bit-level and
is written for a narrow range of platforms, it is not suitable
for general distribution. No software is included with this
archival data set.
Documents
=========
The DOCUMENT directory contains the files that provide documen-
tation and supplementary information to assist in understanding
and using the data products on the volume.
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'.
The above mentioned documents represent the maximum of available docu-
ments, but need not to be present for every measurement. For IFMS
(NNO) measurements, please refer mainly to MRS_DOC, for DSN measure-
ments to DSN_DOC.
Structure of the DOCUMENT directory:
DOCUMENT
|
|- DOCINFO.TXT Specifies the content of
| the document directory
|- MRS_DOC
| |
| |- M32ESOCL1B_RCL_021202_00.PDF Group delay stability
| | .ASC specification and
| | measurements at New Norcia.
| |
| |- M32ESOCL1B_RCL_030522_00.PDF Range calibrations at New
| | .ASC Norcia and Kourou.
| |
| |- M32UNBWL1B_RCL_030801_00.PDF Transponder group veloci-
| | .ASC ties (in German, .ASC in
| | English).
| |
| |- MEX-MRS-IGM-IS-3019.PDF MaRS Data Archive Plan.
| | MEX-MRS-IGM-IS-3019.ASC
| |
| |- MEX-MRS-IGM-IS-3016.PDF MaRS File Naming Convention
| | MEX-MRS-IGM-IS-3016.ASC
| |
| |- MEX-MRS-IGM-MA-3008.PDF MaRS User Manual.
| |
| |- MARS_OPS_LOGBOOK_04.PDF Status of all planned
| | radio science operations
| | in year 2004 (later 05,06)
| |
| |- MEX-MRS-IGM-LI-3028.PDF List of MaRS Team members.
| |
| |- MEX_MRS_IGM_DS_3035.PDF IFMS Doppler Processing and
| | Calibration Software
| | Documentation: Level 1A to
| | Level 2.
| |
| |- MEX_MRS_IGM_DS_3036.PDF IFMS Ranging Processing and
| | Calibration Software
| | Documentation: Level 1A to
| | Level 2.
| |
| |- MEX-MRS-IGM-DS-3037.PDF ODF Processing and Calibra-
| | tion Software: Level 1A to
| | Level 1B. Software Design
| | Specifications
| |
| |- MEX-MRS-IGM-DS-3038.PDF ODF Doppler Processing and
| | Calibration Software: Level
| | 1B to Level2. Software
| | Design Specifications
| |
| |- MEX-MRS-IGM-DS-3039.PDF Radio Science Predicted
| | and Reconstructed Orbit and
| | Planetary Constellation
| | Data: Specifications
| |
| |- MEX-MRS-IGM-DS-3043.PDF ODF Ranging Processing and
| | Calibration Software: Level
| | 1B to Level 2. Software
| | Design Specifications
| |
| |- MEX-MRS-IGM-TN-3045.PDF Reference Systems and Tech-
| | niques for Simulation and
| | Prediction of atmospheric
| | and ionospheric sounding
| | measurements
| |
| |- MEX-MRS-IGM-DS-3046.PDF Radio Science Geometry and
| Position Index Software
| Design Specifications
|
|- ESA_DOC
| |
| |- IFMS-OCCFTP.PDF Documentation of IFMS data
| | format.
| |
| |- MEX-ESC-ID-5003_FDSICD.PDF File format description of
| | ESOC Flight Dynamics files
| | (ancillary files).
| |
| |- MEX-ESC-IF-5003_APPENDIX_C.PDF Documentation of DDS confi-
| | guration.
| |
| |- MEX-ESC-IF-5003_APPENDIX_I.PDF Definition of XML-schema
| | for the data delivery
| | interface.
| |
| |- MEX-ESC-IF-5003_APPENDIX_H.PDF Description of content of
| | ESOC Flight Dynamics files
| | (ancillary files).
| |
| |- MEX-ESC-IF-5003.PDF Data delivery interface
| | document.
| |
| |- SOP-RSSD-TN-010.PDF Planetary Science Data
| | Archive Technical Note Geo-
| | metry and Position Informa-
| | tion
| |
| |- MEX_POINTING_MODE_DESC.TXT Description of pointing
| | modes
| |
| |- ESA-MEX-TN-4009.PDF Mars Express Archive
| Conventions
|
|- DSN_DOC
| |
| |-DSN_DESIGN_HB.PDF/.ASC
| | Technical information and near future configurations of
| | NASA Deep Space Network
| |
| |-DSN_ODF_TRK-2-18.PDF
| | Documentation of Tracking System Interfaces and Orbit Data
| | File Interface
| |
| |-HGA_CALA.ASC
| | High Gain Antenna calibration
| |
| |-HGA_SBDA.PDF
| | S-band antenna patterns
| |
| |-HGA_XBDA.PDF
| | X-band antenna patterns
| |
| |-JPL_D-16765_RSR.PDF
| | Documentation of RSR data format
| |
| |-LIT_SIS.HTM
| | Software Interface Specification: Light Time File
| |
| |-M00DSN0L1A_DKF_yydddhhmm_vv.TXT (optional)
| | DSN Keyword File derived from SOE file and models of
| | activities supported by the DSN
| |
| |-M00DSN0L1A_SOE_yydddhhmm_vv.TXT (optional)
| | Sequence of Events file
| |
| |-MggDSN0L1A_NMC__yydddhhmm_vv.TXT (optional)
| | Network Monitor and Control Logfile
| |
| |-M43SUE0L1A_MFT__yydddhhmm_vv.TXT (optional)
| | Mars Express Manifest file
| |
| |-MEDIASIS.HTM
| | Media Calibration data: formats and contents
| |
| |-MON0158.ASC/.DOC/.PDF (optional)
| | Definition of format and distribution of the real-time,
| | mission monitor data
| |
| |-NMC_SIS.TXT
| | Contents of Network Monitor and Control Log.
| |
| |-OCCLOGnn.TAB
| | Summary information of MEX radio science tests and
| | experiments. nn represents the sequence number.
| |
| |-OPTG_SIS.TXT
| | Software Interface Specification for the Orbit Propagation
| | and Timing Geometry (OPTG) file.
| |
| |-Ryddd.ASC/.DOC/.PDF (optional)
| | Set of notes describing tests before and during radio
| | science tests or operations or the progress of an
| | experiment itself. y represents the year, ddd the DOY.
| |
| |-JPEG
| | Zip-folder with 4 sets of 24 jpeg-files, each from a
| | different receiver, showing circularly polarized received
| | power spectra averaged over 60 seconds. FILENAME:
| | Rydddbca.jpg with y:year, ddd:doy, b:X- or S-band, c: Left
| | or Right-Hand circulation, a:alphabetic numbering for each
| | plot of 60s.
| |
| |-SRX.TXT (optional)
| | Software Interface Specification for Surface Reflection
| | investigation files.
| |
| |-SUE_DMP.ASC/.DOC
| | Data Management Plan
| |
| |-TNF_SIS.TXT
| | Deep Space Mission System External Interface Specification
| |
| |-TRK_2_21.TXT
| | Software Interface Specification
| |
| |-TRK_2_23.TXT / DSN_MEDIA_CAL_TRK_2_23.PDF
| | Specification of DSN media calibration data.
| |
| |-TRK_2_24.TXT / DSN_WEA_FORMAT_TRK_2_24.PDF
| | Specification of DSN weather file.
The documents are either in PDF-Format or are text files in ASCII with
variable length of characters per line. Each line is delimited with a
carriage-return (ASCII 13) line-feed (ASCII 10) pair.
Media/Format
============
The archival data set is written on CD-WO media using the
WinOn CD Creation Software or Nero Burning Rom.
The CD-WO volumes conform to ISO 9660 standards.
More general description of radio science data
==============================================
Closed-loop and Open-loop data:
================================
There are in principle two different ways to record radio
science data: Open-loop and closed-loop data.
The CLOSED-LOOP system used a phase-lock loop in the receiver to
track the downlink signal, reporting both amplitude and fre-
quency at rates typically of 1-10 times per second.
In the OPEN-LOOP system, the signal was simply converted to a
baseband frequency range; the entire passband was sampled and
recorded for later processing. Typical open-loop sampling rates
for MEX were 2000 complex samples per second.
CLOSED-LOOP data are efficient for characterizing slowly
changing signals; OPEN-LOOP data (because of their much higher
volume) are usually used when the signal is very dynamic - such
as during an occultation or bistatic radar measurement.
The data set includes four primary data types with respect to
the two different ground station systems. These systems are on
the one hand the ESA ground station in New Norcia, Australia
(NNO) and the NASA Deep Space Network (DSN).
CLOSED-LOOP data types:
|
|- ESA: Intermediate Frequency Modulation System (IFMS)
| Closed-Loop (CL)
|
| In this data set file names of data recorded at the
| New Norcia IFMS closed loop system start with the
| string 'M32_ICL'
|
| IFMS CL consists of Doppler and Ranging data at
| selected sample rates. The sample rate is usually
| 1/s.
| The only exception are occultation data where the
| sample rate should be 10/s to get a good enough
| vertical resolution of the atmosphere.
| Ranging are only recorded for gravity measurements.
|
| Thus the IFMS closed loop has three recording
| systems IFMS 1, IFMS 2 and IFMS 3
| The standard_data_product_id in the data label
| specifies on which system the data was recorded.
|
| MaRS measurements are usually done in TWO-WAY
| configuration: that is an uplink signal goes up
| (This is usually X-BAND but the uplink signal can
| also be S-Band) and the ground station receives a
| dual frequency simultaneous and coherent downlink
| signal.
|
| IFMS 1 is configured for the uplink signal. It
| receives X-Band downlink if uplink was X-Band and
| S-Band downlink if uplink was S-Band.
| IFMS 2 acts at backup.
| IFMS 3 records the second downlink signal. This is
| usually S-Band. But can also be X-Band when the
| uplink was S-Band.
| From 20.12.04:
| IFMS 1 D1 is fixed to a sample rate of 1/s
| IFMS 1 D2 is on fixed to a sample rate of 1/10s
|
| In addition each Doppler recording system has also
| two Doppler channels which can record simultaneous-
| ly and act as an additional backup system.
| Therefore for each IFMS system there should be at a
| given time two Doppler files and two Auto Gain
| Control files recorded. The file names of these
| data contain the string '_D1' or '_D2' for Doppler
| and '_G1' or '_G2' for Auto Gain control files and
| they will be on different subfolders within the
| data directory. See further down the description of
| the DATA Directory.
|
| For these data files only X-Band ranging was
| possible. Ranging data was nominally recorded on
| IFMS1.
|
|- DSN:
|-Tracking and Navigation File (TNF)
|
| The Tracking and Navigation File (TNF) is the primary out-
| put from the DSN closed-loop receiver system. These are
| large files, accumulating at the rate of approximately 3
| megabytes (MB) per hour of antenna operation. The files
| comprise nearly 20 block types, each designed to carry
| data of interest to a particular navigation, telecommuni-
| cations, or science community.
| The blocks are described by TNF_SIS.TXT in the
| DOCUMENT/DSN_DOC directory. Fields include:
| Uplink and downlink antenna numbers
| Spacecraft number
| Equipment identifiers, status flags, and calibration
| values
| Time tags and frequency bands
| Transmitted and received phase and frequency
| Transmitted and received ranging information
| Noise levels, signal-to-noise ratios, and uncertain-
| ties
|
|-Orbit Data Files (ODF)
|
| For many applications the TNF is too cumbersome. The ODF
| is an edited and partially processed version of the TNF.
| It is a smaller file, often issued in daily increments of
| about 0.2 MB. It contains the most important information
| (range and Doppler)
| needed by spacecraft navigators and investigators
| interested in determining gravitational fields of bodies
| such as Mars. Each ODF is accompanied by a full PDS label
| which describes both the content and format of the
| associated file. ODF data fields include:
| Narrowband spacecraft VLBI, Doppler mode (cycles)
| Narrowband spacecraft VLBI, phase mode (cycles)
| Narrowband quasar VLBI, Doppler mode (cycles)
| Narrowband quasar VLBI, phase mode (cycles)
| Wideband spacecraft VLBI (nanoseconds)
| Wideband quasar VLBI (nanoseconds)
| One-way Doppler (Hertz)
| Two-way Doppler (Hertz)
| Three-way Doppler (Hertz)
| One-way total count phase (cycles)
| Two-way total count phase (cycles)
| Three-way total count phase (cycles)
| PRA planetary operational discrete spectrum range (range
| units)
| SRA planetary operational discrete spectrum range (range
| units)
| RE(GSTDN) range (nanoseconds)
| Azimuth angle (degrees)
| Elevation angle (degrees)
| Hour angle (degrees)
| Declination angle (degrees)
|
| For more information please refer to document
| [DSN_ODF_TRK-2-18] in the DOCUMENT/DSN_DOC folder.
Open- Loop data types:
|
|-ESA: Intermediate Frequency Modulation System (IFMS) Open-Loop
| (OL)
|
| During the commissioning phase the IFMS Open-Loop
| recording system was not implemented, yet.
|
|-DSN: Radio- Science Receiver (RSR)
|
| The Radio Science Receiver (RSR) is a computer-
| controlled open loop receiver that digitally records a
| spacecraft signal through the use of an analog to
| digital converter (ADC) and up to four digital filter
| sub-channels. The digital samples from each
| sub-channel are stored to disk in one second records
| in real time. In near real time the one second records
| are partitioned and formatted into a sequence of RSR
| Standard Format Data Units (SFDUs) which are
| transmitted to the Advanced Multi-Mission Operations
| System (AMMOS) at the Jet Propulsion Laboratory (JPL).
| Included in each RSR SFDU are the ancillary data
| necessary to reconstruct the signal represented by the
| recorded data samples.
|
| Each SFDU is defined here as a single row in a
| PDS TABLE object; later SFDUs are later rows. The
| first fields in each row contain the ancillary data
| (time tags and frequency estimates, for example) that
| applied while the samples at the end of the record
| were being collected. The object definitions below
| explain where the fields are and what the contents
| represent.
|
| Analysis of variations in the amplitude, frequency,
| and phase of the recorded signals provides information
| on the ring structure, atmospheric density, magnetic
| field, and charged particle environment of planets
| which occult the spacecraft. Variations in the
| recorded signal can also be used for detection of
| gravitational waves.
|
| DSN open-loop receivers sample a narrow part of the micro-
| wave spectrum near the spacecraft transmitting frequency.
| For radio occultation tests, two RSR's were used - one
| each for X-RCP and S-RCP with output sampled at rates of
| 2000 (complex; 16-bit I, 16-bit Q).
| The data were examined for compliance with data acquisi-
| tion procedures and to measure the frequency/stability of
| the radiolink. Four RSR's (X-RCP, S-RCP, X-LCP, and S-LCP)
| each sample at a rate of 25000 (complex; 16-bit I,
| 16-bit Q) to test bistatic radar data acquisition.
|
| Header information accompanying each RSR record included:
|
| Date and time of the first data sample
| Sample rate and channel assignments
| Receiver local oscillator phase and frequency
| Attenuator settings
| RMS voltages at several stages in the receiving chain
|
|
| For more information please refer to document
| [JPL_D-16765_RSR] in the DOCUMENT/DSN_DOC folder.
|
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