urn:nasa:pds:radiosci.documentation:dsn.0159-science:i070172a
1.1
Example MRO-mode RSR File - for use with documentation
1.16.0.0
Product_Observational
Simpson, R. A.
2020
Example Mars Express radio occultation data from 2018
for use with documentation explaining how to interpret
and use binary RSR files. This file contains data that
were captured in the RSR MRO mode.
2021-08-25
1.1
Updated to IM v1.16.0.0
2020-02-24
1.0
Initial version
2018-03-11T17:27:01Z
2018-03-11T17:27:04Z
Science
Raw
Example Mars Express radio occultation data from 2018
for use with documentation explaining how to interpret
and use binary RSR files. This file contains data that
were captured in the RSR MRO mode.
Mars Express
Mission
urn:nasa:pds:context:investigation:mission.mars_express
data_to_investigation
Mars Express
Host
urn:nasa:pds:context:instrument_host:spacecraft.mex
is_instrument_host
Mars Express Radio Science
Instrument
M. Pätzold, S. Tellmann, T. Andert, L. Carone, M. Fels, R. Schaa, C. Stanzel,
I. Audenrieth-Kersten, A. Gahr, A.-L. Müller, B. Stracke, D. Stupar, C. Walter,
B. Häusler, S. Remus, J. Selle, H. Griebel, W. Eidel, S. Asmar, G. Goltz, D. Kahan,
J.-P. Barriot, V. Dehant, M. Beuthe, P. Rosenblatt, Ö. Karatekin, V. Lainey,
G.L. Tyler, D. Hinson, R. Simpson, and J. Twicken.
MaRS: Mars Express Radio Science Experiment, pages 217-245,
in Mars Express: The Scientific Investigations,
European Space Agency SP-1291, June 2009.
https://sci.esa.int/documents/33745/35957/1567258041276-MaRS.pdf
The Mars Express Radio Science Experiment (MaRS) started regular operations in April 2004.
The experiment employed radio occultation during two occultation seasons in April-August 2004
and December 2004 to sound the neutral martian atmosphere to derive vertical density, pressure
and temperature profiles as functions of height, and to sound the ionosphere to derive vertical
ionospheric electron density profiles. Both profile types were monitored as functions of time
in order to determine diurnal variations and, in the case of the ionosphere, dependence on
solar wind conditions. MaRS also determined the dielectric and scattering properties of the
martian surface in specific target areas by using bistatic radar, determining gravity anomalies
during pericentre passes at altitudes of 250 km for investigations of the structure and
evolution of the crust and lithosphere, and sounding the solar corona during the superior
conjunction of Mars with the Sun from mid-August to mid-October 2004. This document provides
an overview of the observations and analysis techniques using data from April 2004 to mid-2005.
(Adapted from the paper's abstract).
Mars
Planet
urn:nasa:pds:context:target:planet.mars
data_to_target
i070172a.rsr
2020-02-24T12:00:00
24780
569f9e2c952f96434bb3ef1a91187450
Mars Express Radio Science Receiver (RSR) raw data
0
3
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 record in a PDS Table_Binary; later
SFDUs are later records. The first fields in each record 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 definitions below explain where the fields are and what the contents
represent.
The VSR is a very similar device, used for VLBI recording at the DSN.
Software developed by the JPL Radio Science Systems Group at JPL converts
VSR data into formats which are identical to those from the RSR. These
VSR-derived files may be identified by a different value (5) in the
MINOR DATA CLASS field of the PRIMARY HEADER CHDO (column 13). The
ORIGINATOR ID and the LAST MODIFIER ID should also be different. Values
in other fields (SUB-CHANNEL IDENTIFIER, DIG ADC YEAR, DIG ADC DAY OF
YEAR, and FGAIN IF BANDWIDTH) may also be different.
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.
71
1
8260
SFDU Control Authority
1
1
ASCII_String
4
An ASCII string giving the SFDU Control Authority for this data
type. Set to "NJPL", meaning the data description information for
this type of SFDU is maintained by the NASA/JPL Control Authority.
SFDU Label Version ID
2
5
ASCII_String
1
An ASCII character giving the SFDU Label Version Identifier. Set to
"2", meaning the length given in bytes 13-20 is formatted as a
binary unsigned integer.
SFDU Class ID
3
6
ASCII_String
1
An ASCII character giving the SFDU Class Identifier. Set to "I",
meaning this is a Compressed Header Data Object (CHDO) structured SFDU.
SFDU Reserved
4
7
SignedMSB2
2
These two bytes are not defined.
SFDU Data Description ID
5
9
ASCII_String
4
An ASCII string giving the SFDU Data Description Identifier. Set to
"C997", a unique identifier for the RSR data type within the NASA/JPL
Control Authority.
SFDU RSR Length Pad
6
13
UnsignedMSB4
4
The high-order 32 bits of a 64-bit unsigned binary integer giving the
number of remaining bytes in the SFDU after the 20-byte label.
Always "0" in the RSR SFDU.
SFDU RSR Length
7
17
UnsignedMSB4
4
byte
The number of remaining bytes in the SFDU after the 20-byte label.
Always less than 31000.
Header Aggregation CHDO Type
8
21
UnsignedMSB2
2
Header Aggregation CHDO Type. Set to "1", meaning this CHDO is an
aggregation of header CHDOs. The NJPL Control Authority maintains a
registry of CHDO types.
Header Aggregation CHDO Length
9
23
UnsignedMSB2
2
byte
Header Aggregation CHDO Length. Set to "232", meaning length of the
value field of the Header Aggregation CHDO is 232 bytes (bytes 25-256).
Primary Header CHDO Type
10
25
UnsignedMSB2
2
Primary Header CHDO Type. Set to to "2", meaning this CHDO is a
primary header CHDO. The NJPL Control Authority maintains a
registry of CHDO types.
Primary Header CHDO Length
11
27
UnsignedMSB2
2
byte
Primary Header CHDO Length. Set to "4", meaning length of the value
field of the Primary Header CHDO is 4 bytes (bytes 29-32).
Major Data Class
12
29
UnsignedByte
1
Major Data Class. Set to "21", meaning this SFDU contains Radio
Science data.
Minor Data Class
13
30
UnsignedByte
1
Minor Data Class. Set to "4" if these are Radio Science Receiver data from
the DSN. Set to "5" is these are VSR data which have been converted to the
RSR format.
Mission Identifier
14
31
UnsignedByte
1
Mission Identifier. Set to "0", meaning the RSR does not use this
field. The value may be changed if the Ground Data System handles
the data. If a Mission Identifier is needed, values may be found in
DSN document 820-013, OPS-6-21A, Table 3-4.
Format Code
15
32
UnsignedByte
1
Format Code. Set to "0". The RSR supports only one data format.
Secondary Header CHDO Type
16
33
UnsignedMSB2
2
Secondary Header CHDO Type. Set to to "104", meaning this CHDO is an
RSR secondary header CHDO. The NJPL Control Authority maintains a
registry of CHDO types.
Secondary Header CHDO Length
17
35
UnsignedMSB2
2
byte
Secondary Header CHDO Length. Set to "220", meaning length of the value
field of the Secondary Header CHDO is 220 bytes (bytes 37-256).
Originator ID
18
37
UnsignedByte
1
Originator Identifier. A value "48" means the data originated within the
DSN. A value "123" means these data originated in the JPL Radio Science
Systems Group.
Last Modifier ID
19
38
UnsignedByte
1
Last Modifier Identifier. A value "48" means the contents of the SFDU
were last modified by the DSN. A value "123" means these data were
last modified by the JPL Radio Science Systems Group.
RSR Software ID
20
39
UnsignedMSB2
2
RSR Software Identifier. The version of the RSR software is indicated by
an unsigned binary integer between 0 and 65535.
Record Sequence Number
21
41
UnsignedMSB2
2
The Record Sequence Number (RSN) starts at 0 for the first RSR SFDU
and increments by 1 for each successive SFDU to a maximum of
65535, after which it resets to 0 and begins incrementing again.
The RSN may be reset at other times, such as when the RSR is started or
restarted. The RSN is provided by the originator of the SFDU and should
not be changed during subsequent handling or modification.
Signal Processing Center
22
43
UnsignedByte
1
Signal Processing Center (SPC) Identifer. Valid numbers include
10 Goldstone
40 Canberra
60 Madrid
21 DTF21
Deep Space Station
23
44
UnsignedByte
1
Deep Space Station (DSS) Identifier. This is the DSS identifier listed in
the frequency predicts file used to collect the data in this SFDU. DSS
identifiers are listed in DSN document 820-013, OPS-6-3 and include
valid numbers such as 14, 15, 25, 43, 45, 54, and 63.
Radio Science Receiver
24
45
UnsignedByte
1
Radio Science Receiver (RSR) Identifier. Values can be in the
range 1-16 and specify the RSR used to collect the data in this SFDU.
For example,
RSR ID = 1 denotes RSR1A
RSR ID = 2 denotes RSR1B
RSR ID = 3 denotes RSR2A
The SPC ID and RSR ID uniquely specify the hardware used in the
data acquisition. SPC 10 has three RSR racks; SPC 40 and SPC 60 each
have two. Each rack has two receivers (A and B). Except for the
analog components in the ADCs, the end-to-end performance of every RSR
should be identical. For data derived from a VSR, the values and their
meanings are different.
Sub-channel Identifier
25
46
UnsignedByte
1
Sub-Channel Identifier. This can be in the range 1-4 and specifies the
RSR sub-channel used to acquire the the data in this SFDU. If the data
originated in a VSR, the permissible range is 0-15, assigned as follows:
0 = 1N1
1 = 1N2
2 = 1W1
3 = 1W2
4 = 2N1
...
15 = 4W2
There are two narrow band (N or NB) subchannels and two wide band (W or WB)
subchannels for each of up to 4 channels on each VSR.
Secondary Header CHDO Reserved
26
47
UnsignedByte
1
This field is not used.
Spacecraft
27
48
UnsignedByte
1
Spacecraft Identifier, as listed in the frequency predicts file used to
collect the data in this SFDU. Values are assigned by the Deep Space
Mission System (DSMS) and are in the range 0-255. Assignments are given
in DSN document 820-013, OPS-6-21A, Table 3-4.
Predicts Pass Number
28
49
UnsignedMSB2
2
Predicts Pass Number (range 0-65535) gives the DSN pass number in the
predicts file used to collect the data in this SFDU.
Uplink Frequency Band
29
51
ASCII_String
1
The Uplink Frequency Band specified in the predicts file used to collect
the data in this SFDU. Possible values include:
"S" S-Band
"X" X-Band
"K" Ka-Band
Downlink Frequency Band
30
52
ASCII_String
1
The Downlink Frequency Band specified in the predicts file used to collect
the data in this SFDU. Possible values include:
"S" S-Band
"X" X-Band
"K" Ka-Band
Tracking Mode
31
53
UnsignedByte
1
The Tracking Mode in use when the data in this SFDU were acquired.
Possible values are:
"S" S-Band
"X" X-Band
"K" Ka-Band
Uplink DSS ID for 3-Way Tracking
32
54
UnsignedByte
1
Deep Space Station (DSS) Identifier for the uplink antenna when
TRACKING_MODE=3; otherwise, undefined. DSS identifiers are
listed in DSN document 820-013, OPS-6-3 and include valid numbers
such as 14, 15, 25, 43, 45, 54, and 63.
FGAIN
33
55
SignedByte
1
deciBel per Hertz
Expected ratio of signal power to noise power in a one Hz bandwidth
when the data in this SFDU were collected. This parameter is used
to estimate the sample voltage amplitudes at the RSR output and to
compute settings of the sub-channel filter gain so that there is no
clipping of the sample values. Possible values are in the range
-127 to +128.
FGAIN IF Bandwidth
34
56
UnsignedByte
1
megahertz
IF Bandwidth expected to be in use by the RSR at the time the data in
this SFDU were acquired. This value is used to compute the settings of
the sub-channel filter gain. Values can be in the range 1-127. If the
data originated in a VSR, this value may be set to "0".
FROV Flag
35
57
UnsignedByte
1
Frequency Predicts Override Flag. Set to "0", this indicates that the
frequency predicts file was in use; any other value indicates that the
frequency specified by the FROV command was in use. The value of the
override frequency is given by PREDICTS_FREQUENCY_OVERRIDE in Column 51.
DIG Attenuation
36
58
UnsignedByte
1
RSR Digitizer Subassembly (DIG) setting. Values are in the range
0-63, which correspond to 0.5 dB increments in attenuation.
DIG ADC RMS
37
59
UnsignedByte
1
Root-mean-square amplitude of about 10000 8-bit samples taken from the DIG
ADC stream. Time of the measurement is stored in fields 39-41.
DIG ADC Peak
38
60
UnsignedByte
1
Peak amplitude from about 10000 8-bit samples taken from the DIG ADC stream.
Time for the measurement is stored in fields 39-41.
DIG ADC Year
39
61
UnsignedMSB2
2
UTC year on which the ADC data were computed. Values can range over
1900-3000. If the data originated in a VSR, this field may be set to "0".
DIG ADC Day of Year
40
63
UnsignedMSB2
2
UTC day-of-year on which the ADC data were computed. Values can range
over 1-366. If the data originated in a VSR, this field may be set to "0".
DIG ADC Second
41
65
UnsignedMSB4
4
second
UTC second of day on which the ADC data were computed. Values can
range over 0-86400.
Sample Resolution
42
69
UnsignedByte
1
bit
Bits per sample in the data in this SFDU. Valid values are 1, 2, 4, 8, and
16 and are selected by the RSR operator while it is in configure state.
Data Error Count
43
70
UnsignedByte
1
Number of hardware errors encountered while the data in this SFDU were
being recorded. Values can range over 0-255, but any value greater than 0
indicates data may have been corrupted by hardware errors.
Sample Error Rate
44
71
UnsignedMSB2
2
kilosample per second
The rate at which samples were collected in this SFDU. Sample rate
(or bandwidth) is specified by the operator while the RSR is in the
configure state.
DDC LO Frequency
45
73
UnsignedMSB2
2
megahertz
Digital Down Converter (DDC) Local Oscillator (LO) Frequency. This
specifies the downconversion applied to the signal in the DIG and DDC.
This frequency is needed to compute the sky frequency of the data in
this SFDU:
Fsky = RFtoIF_LO + DDC_LO - NCO_Freq + Fresid
where
RFtoIF_LO is in field 46,
DDC_LO is in field 45,
NCO_Freq is from fields 61-63, and
Fresid is the signal offset from DC in the RSR data.
RF-IF LO Frequency
46
75
UnsignedMSB2
2
megahertz
RF to IF Down Converter Local Oscillator (LO) Frequency. This
specifies the total downconversion applied to the signal before it
entered the RSR DIG. The value is subtracted from the RF predict
points in order to obtain the frequency of the desired signal at
IF. The RSR selects a default value based on the downlink band: 2000
(S-Band), 8100 (X-Band), or 31700 (Ka-Band). This frequency is needed
in order to reconstruct the sky frequency of the data contained in
this SFDU:
Fsky = RFtoIF_LO + DDC_LO - NCO_Freq + Fresid
where
RFtoIF_LO is in field 46,
DDC_LO is in field 45,
NCO_Freq is from fields 61-63, and
Fresid is the signal offset from DC in the RSR data.
SFDU Year
47
77
UnsignedMSB2
2
UTC year for the SFDU data and models. Values can range over 1900-3000.
SFDU Day of Year
48
79
UnsignedMSB2
2
UTC day-of-year for the SFDU data and models. Values can range over 1-366.
SFDU Second
49
81
IEEE754MSBDouble
8
second
UTC seconds of day for the SFDU data and models. Values can range over 0-86400.
Predicts Time Shift
50
89
IEEE754MSBDouble
8
The number of seconds added to the time tags of the frequency predicts
to shift them in time. This feature allows testing the RSR with old
predict files. The value should be 0.0 during normal operations.
Predicts Frequency Override
51
97
IEEE754MSBDouble
8
hertz
The value of the predicts frequency override specified by the FROV
command; this constant value is substituted for the value derived
from the predicts. The flag in field 35 indicates whether the
frequency override is active.
Predicts Frequency Rate
52
105
IEEE754MSBDouble
8
hertz/second
The frequency rate added to the RF frequency predicts as specified by
the FRR command. The allowable range is -8000 to +8000 hertz/second.
Predicts Frequency Offset
53
113
IEEE754MSBDouble
8
hertz
The total frequency added to the RF frequency predicts as specified by
the FRO command and the accumulated frequency rate as specified by the
FRR command. The allowable range is -8 to +8 MHz.
Sub-channel Frequency Offset
54
121
IEEE754MSBDouble
8
hertz
The frequency added to the frequency predicts for this sub-channel as
specified by the SFRO command.
RF Point 1
55
129
IEEE754MSBDouble
8
hertz
The radio frequency at the beginning of the second as calculated from the predicts.
RF Point 2
56
137
IEEE754MSBDouble
8
hertz
The radio frequency at the middle of the second as calculated from the predicts.
Set to IEEE NaN (hex 7FFFFFFFFFFFFFFF) if not calculable.
RF Point 3
57
145
IEEE754MSBDouble
8
hertz
The radio frequency at the end of the second as calculated from the predicts.
Set to IEEE NaN (hex 7FFFFFFFFFFFFFFF) if not calculable.
Sub-channel Frequency Point 1
58
153
IEEE754MSBDouble
8
hertz
The sub-channel frequency at the beginning of the second. This point
is used to create the sub-channel frequency and phase polynomials.
Sub-channel Frequency Point 2
59
161
IEEE754MSBDouble
8
hertz
The sub-channel frequency at the middle of the second. This point
is used to create the sub-channel frequency and phase polynomials.
Set to IEEE NaN (hex 7FFFFFFFFFFFFFFF) if not calculable.
Sub-channel Frequency Point 3
60
169
IEEE754MSBDouble
8
hertz
The sub-channel frequency at the end of the second. This point
is used to create the sub-channel frequency and phase polynomials.
Set to IEEE NaN (hex 7FFFFFFFFFFFFFFF) if not calculable.
Sub-channel Frequency Coefficient F1
61
177
IEEE754MSBDouble
8
hertz
The sub-channel frequency polynomial coefficient F1 where the frequency
over a one millisecond interval beginning at t in msec is evaluated
F(t) = F1 + F2*((t+0.5)/1000) + F3*((t+0.5)/1000)**2
The coefficients are derived from the frequency points in fields 58-60.
Sub-channel Frequency Coefficient F2
62
185
IEEE754MSBDouble
8
hertz
The sub-channel frequency polynomial coefficient F2 where the frequency
over a one millisecond interval beginning at t in msec is evaluated
F(t) = F1 + F2*((t+0.5)/1000) + F3*((t+0.5)/1000)**2
The coefficients are derived from the frequency points in fields 58-60.
Set to IEEE NaN (hex 7FFFFFFFFFFFFFFF) if not calculable.
Sub-channel Frequency Coefficient F3
63
193
IEEE754MSBDouble
8
hertz
The sub-channel frequency polynomial coefficient F3 where the frequency
over a one millisecond interval beginning at t in msec is evaluated
F(t) = F1 + F2*((t+0.5)/1000) + F3*((t+0.5)/1000)**2
The coefficients are derived from the frequency points in fields 58-60.
Set to IEEE NaN (hex 7FFFFFFFFFFFFFFF) if not calculable.
Sub-channel Accumulated Phase
64
201
IEEE754MSBDouble
8
cycle
The accumulated whole turns of the sub-channel phase at the beginning of
the present second. The phase during this second is the accumulated phase
incremented by the phase computed using the coefficients in fields 65-68.
Sub-channel Phase Coefficient P1
65
209
IEEE754MSBDouble
8
cycle
The sub-channel phase polynomial coefficient P1 where the phase
over a one millisecond interval beginning at t in msec is evaluated
P(t) = P1 + P2*((t+0.5)/1000) + P3*((t+0.5)/1000)**2 + P4*((t+0.5)/1000)**3
The coefficients are derived from the frequency points in fields 58-60.
Sub-channel Phase Coefficient P2
66
217
IEEE754MSBDouble
8
cycle
The sub-channel phase polynomial coefficient P2 where the phase
over a one millisecond interval beginning at t in msec is evaluated
P(t) = P1 + P2*((t+0.5)/1000) + P3*((t+0.5)/1000)**2 + P4*((t+0.5)/1000)**3
The coefficients are derived from the frequency points in fields 58-60.
Set to IEEE NaN (hex 7FFFFFFFFFFFFFFF) if not calculable.
Sub-channel Phase Coefficient P3
67
225
IEEE754MSBDouble
8
cycle
The sub-channel phase polynomial coefficient P3 where the phase
over a one millisecond interval beginning at t in msec is evaluated
P(t) = P1 + P2*((t+0.5)/1000) + P3*((t+0.5)/1000)**2 + P4*((t+0.5)/1000)**3
The coefficients are derived from the frequency points in fields 58-60.
Set to IEEE NaN (hex 7FFFFFFFFFFFFFFF) if not calculable.
Sub-channel Phase Coefficient P4
68
233
IEEE754MSBDouble
8
cycle
The sub-channel phase polynomial coefficient P4 where the phase
over a one millisecond interval beginning at t in msec is evaluated
P(t) = P1 + P2*((t+0.5)/1000) + P3*((t+0.5)/1000)**2 + P4*((t+0.5)/1000)**3
The coefficients are derived from the frequency points in fields 58-60.
Set to IEEE NaN (hex 7FFFFFFFFFFFFFFF) if not calculable.
SPARES
69
241
ComplexMSB16
16
cycle
These 16 bytes are undefined.
Data CHDO Type
70
257
UnsignedMSB2
2
Data CHDO Type. Set to "10", meaning this CHDO contains binary data. The
NJPL Control Authority maintains a registry of CHDO types.
Data CHDO Length
71
259
UnsignedMSB2
2
byte
Data CHDO Length. Gives the number of bytes in the value field of the Data
CHDO -- the number of bytes containing I and Q samples.
I/Q Pair
1
2000
2
0
Each ITEM contains one 32-bit sample word: quadrature (Q) sample data in
the 16 most significant bits (MSBs) followed by in-phase (I) sample data
in the 16 least significant bits (LSBs). Within each Q and I word,
individual outputs from the analog to digital converters (ADCs) are
stored as 1, 2, 4, 8, or 16 bit values in LSB to MSB time order (the sample
size is set in Column 42). For example, if the data were collected
using 8-bit samples, the arrangement would be
BYTES 1-2
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
BITS |1|2|3|4|5|6|7|8|1|2|3|4|5|6|7|8|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|-------Q2------|-------Q1------|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
BYTES 3-4
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
BITS |1|2|3|4|5|6|7|8|1|2|3|4|5|6|7|8|
|-------I2------|-------I1------|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
where (Q1,I1) is the earlier sample
and (Q2,I2) was taken later.
261
8000
Q
1
1
UnsignedMSB2
2
The imaginary part of a complex data sample
I
2
3
UnsignedMSB2
2
The real part of a complex data sample