SCE Contact:
Dr. Michael K. Bird
Radioastronomisches Institut
Universitaet Bonn
Auf dem Huegel 71
53121 Bonn
Germany
Phone: (49) 228-733651
Telefax: (49) 228-733672
E-mail: mbird@astro.uni-bonn.de
Ulysses Solar Corona Experiment (SCE)
The Ulysses dual-frequency radio subsystem was utilized by the Ulysses
Solar Corona Experiment (SCE) to measure the electron content
(column density) and its variations during the first solar conjunction
(C1) of the Ulysses mission in the summer of 1991 as well as the fourth
solar conjunction (C4) in the winter of 1995. In the nominal mode for
radio-sounding observations [BIRDETAL1992A], both downlinks (S-band:
f_s = 2.3 GHz; X-band: f_x = 8.4 GHz) are phase coherent with the uplink
(S-band: f_u = 2.1 GHz). The dual-frequency radio-sounding technique
exploits the dispersive nature of ionized media on the propagation of
the two downlinks. The tiny Doppler shift due to plasma moving in and
out of the ray path is greater at S-band than at the higher frequency
X-band. Similarly, because the group velocity of waves propagating in
ionized media is smaller for lower frequencies, the round-trip time of
propagation for coded range signals between the spacecraft and the
ground station will be longer at S-band than at X-band.
SCE Data Types
The SCE data are obtained from the Radio Science Support group at JPL
[ASMAR&RENZETTI1993; ASMARETAL1995]. There are basically two types of
data: ranging and Doppler (Frequency), recorded at the tracking sites
of the NASA Deep Space Network (DSN) as a function of UT Ground Received
Time [DSN810-5]. The raw data are delivered in special binary files
called ATDFs (Archival Tracking Data Files), containing ranging and
Doppler data from the standard DSN tracking receivers. There are high
time resolution Doppler data from special radio science receivers
(so-called 'open loop' data) as well. These are in files called ODRs
(Original Data Records).
ATDFs are files of radiometric data produced by the Network Operations
Control Center (NOCC) Navigation Subsystem (NAV). They are derived
from Intermediate Data Records by NAV and contain all radiometric
measurements received from the DSN station including signal levels
(`AGC' = automatic gain control in dBm), antenna pointing angles,
frequency (often referred to simply as `Doppler'), range, and residuals.
Doppler data are often used to infer spacecraft radial motion relative
to the tracking antenna. Data values in ATDFs are reported at rates no
higher than 10 per second. For the Ulysses solar conjunction C1 the
received frequencies at S-Band and X-band were recorded at a nominal
sample time of one per second. Ranging data were recorded nominally at
intervals of ca. 10 minutes. Each ATDF data record contains 117
parameters, stored in records of 288 bytes. The ATDF is described in
section TRK-2-25 of the JPL Document 820-13 [DSN820-13].
SCE Data Recording Opportunities
The ranging data from the ATDFs have been analyzed for the solar
conjunction C1 and a number of publications describe the results
[PAETZOLDETAL1992; BIRDETAL1994; WOOETAL1995A; WOOETAL1995B; WOO1996;
PAETZOLDETAL1997]. Ranging results from the geometrically unique fourth
Ulysses solar conjunction (C4) are also available [PAETZOLDETAL1995;
BIRDETAL1996; WOO&HABBAL1997; PAETZOLD&BIRD1998; WOO&HABBAL1998].
Coronal velocities as a function of solar distance were derived
from the C1 Doppler data using a correlation technique between
uplink and downlink [WOHLMUTHETAL1997] and between two simultaneously
tracking ground stations [JANARDHANETAL1999]. Differences in the
spectral characteristics of electron density fluctuations observed
in coronal holes vs. corona streamers were reported from analyses of
the C4 Doppler data [PAETZOLDETAL1996; KARLETAL1997]. The Ulysses
radio subsystem was utilized during the Jupiter encounter to measure
the columnar electron density of the Io Plasma Torus [BIRDETAL1992B;
BIRDETAL1993]. These data, together with all Ulysses results from
the Jupiter encounter, are archived at the Planetary Data System (PDS).
SCE Ranging Data Processing
Data files have been generated which contain the ranging data at an
advanced stage of processing. After stripping the ranging data from
the ATDFs and weeding out obviously bad data, tables of the measured
data plus physically relevant quantities were produced for the archive
as function of time.
Ranging data during the Ulysses solar conjunctions C1 (7 August to 5
September 1991) and C4 (23 February to 14 March 1995) have been provided
to this archive in the RANGE_C1.DAT and RANGE_C4.DAT files.
As an example, the first few lines of RANGE_C1.DAT are as follows:
year mo dd hh:mm:ss set no dss difrng econt
1991- 8- 7T 1:11:23.712Z 1 1 43 557 2227
1991- 8- 7T 1:21:24.192Z 1 2 43 555 2219
1991- 8- 7T 1:31:24.672Z 1 3 43 567 2267
1991- 8- 7T 1:41:24.288Z 1 4 43 575 2299
1991- 8- 7T 1:51:23.904Z 1 5 43 578 2311
1991- 8- 7T 2: 1:23.520Z 1 6 43 574 2295
1991- 8- 7T 2:11:24.000Z 1 7 43 567 2267
1991- 8- 7T 2:21:23.616Z 1 8 43 575 2299
1991- 8- 7T 2:31:23.232Z 1 9 43 584 2335
1991- 8- 7T 2:41:23.712Z 1 10 43 570 2279
1991- 8- 7T 2:51:24.192Z 1 11 43 572 2287
1991- 8- 7T 3: 1:24.672Z 1 12 43 582 2327
1991- 8- 7T 3:11:24.288Z 1 13 43 591 2363
1991- 8- 7T 3:31:23.520Z 1 14 43 596 2383
1991- 8- 7T 3:41:24.000Z 1 15 43 588 2351
where:
year : 1991
mo : month of year
dd : day of month
hh:mm:ss : hours, minutes seconds (UT, ground received)
set : running no. for each DSN tracking pass during C1, C4, resp.
no : running no. for range measurement within each tracking pass
dss : DSN station number
difrng : differential range delay in `range units' (RU) [DSN810-5]
econt : electron content in `hexems' [BIRDETAL1992A; BIRDETAL1994]
note: difrng (RU) and econt (hexems) are given to the nearest
respective unit. The estimated accuracy of a differential
range measurement is of the order of 50 range units.
The following table gives information about the size and coverage of
the Ulysses SCE ranging data set from the two solar conjunctions:
Conj Year start stop ascii size gzip size
mo:dd:hh:mm mo:dd:hh:mm (kB) (kB)
C1 1991 08:07:01:11 09:05:17:55 88 20
C4 1995 02:23:05:06 03:14:14:06 145 33
SCE Doppler Data Processing
Data files have been generated from the ATDFs which contain the
quantities of interest for analysis of the Ulysses downlink frequencies.
The data set for the first solar conjunction C1 in 1991 from DOY 218-248
(6 August to 5 September) consists of the following files :
DOP91218-063.gz DOP91227-012.gz DOP91235-043.gz DOP91242-014.gz
DOP91219-043.gz DOP91227-043.gz DOP91235-063.gz DOP91242-043.gz
DOP91219-061.gz DOP91227-063.gz DOP91236-014.gz DOP91243-014.gz
DOP91220-043.gz DOP91228-014.gz DOP91236-043.gz DOP91243-063.gz
DOP91221-014.gz DOP91228-063.gz DOP91237-014.gz DOP91244-014.gz
DOP91221-043.gz DOP91229-014.gz DOP91237-063.gz DOP91244-063.gz
DOP91221-143.gz DOP91229-043.gz DOP91238-014.gz DOP91245-014.gz
DOP91222-014.gz DOP91229-063.gz DOP91238-043.gz DOP91245-063.gz
DOP91222-043.gz DOP91230-014.gz DOP91238-063.gz DOP91246-014.gz
DOP91223-014.gz DOP91230-063.gz DOP91239-014.gz DOP91246-043.gz
DOP91223-043.gz DOP91231-014.gz DOP91239-043.gz DOP91247-014.gz
DOP91224-014.gz DOP91231-063.gz DOP91239-063.gz DOP91248-014.gz
DOP91224-063.gz DOP91232-014.gz DOP91240-014.gz DOP91248-043.gz
DOP91225-014.gz DOP91233-014.gz DOP91240-063.gz datalist_c1.txt
DOP91225-063.gz DOP91234-014.gz DOP91241-012.gz
DOP91226-014.gz DOP91234-043.gz DOP91241-043.gz
DOP91226-063.gz DOP91234-063.gz DOP91241-063.gz
The data set for the fourth solar conjunction C4 in 1995 from DOY 53-73
(22 February to 14 March) consists of the following files :
DOP95053-042.gz DOP95057-042.gz DOP95063-042.gz DOP95069-012.gz
DOP95054-012.gz DOP95057-061.gz DOP95063-061.gz DOP95069-042.gz
DOP95054-061.gz DOP95057-142.gz DOP95064-061.gz DOP95069-061.gz
DOP95054-161.gz DOP95057-161.gz DOP95065-042.gz DOP95070-042.gz
DOP95055-042.gz DOP95058-061.gz DOP95065-061.gz DOP95070-061.gz
DOP95055-061.gz DOP95059-042.gz DOP95065-142.gz DOP95071-012.gz
DOP95055-142.gz DOP95059-061.gz DOP95066-042.gz DOP95071-042.gz
DOP95055-161.gz DOP95060-042.gz DOP95066-061.gz DOP95071-061.gz
DOP95056-012.gz DOP95060-061.gz DOP95067-012.gz DOP95072-042.gz
DOP95056-042.gz DOP95061-012.gz DOP95067-042.gz DOP95072-061.gz
DOP95056-061.gz DOP95061-042.gz DOP95067-061.gz DOP95073-042.gz
DOP95056-161.gz DOP95062-042.gz DOP95068-012.gz DOP95073-061.gz
DOP95057-012.gz DOP95062-061.gz DOP95068-042.gz datalist_c4.txt
The "gz" suffex means that these files have been compressed with the
UNIX gzip utility. They can be expanded to ascii tables with the
analog gunzip utility. Each file contains dual-frequency Doppler
data at a sample rate of 1 point per second from each tracking pass.
The filename provides the day-of-year (doy) and ground tracking station
(dss) according to the scheme "DOPyydoy-dss", where the year number is
yy = 91 (C1) or 95 (C4). The doy given to each file applies to the
start of the data recording. The deep space stations of the NASA Deep
Space Network (DSN) used for SCE are:
DSS 12 : Goldstone 34-m
DSS 14 : Goldstone 70-m
DSS 42 : Canberra 34-m
DSS 43 : Canberra 70-m
DSS 61 : Madrid 34-m
DSS 63 : Madrid 70-m
Some tracking passes, especially at the Canberra stations, continue on
into the next doy. Normally, a "0" preceeds the dss number. The few
cases with a "1" rather than "0" are a separate tracking pass at the
same dss later on the same doy. The files "datalist_c1.txt" and
"datalist_c4.txt" contain listings of each tracking pass with such
information as date, ATDF number, start and end times of pass, start
and end times of data recording, pass duration, station overlaps, etc.
Each file contains 15 columns per data point defined as follows:
column explanation
1-4 : time tag (UT, ground received)
1 : DOY in 1991 (C1) or 1995 (C4)
2 : HH
3 : MM
4 : SS
5 : DSS
6 : uplink frequency [Hz]
7-10 : S-band receiver parameters
7 : agc [dBm]
8 : downlink frequency [Hz]
9 : downlink frequency residual [Hz]
10 : total slipped cycles during count
11-14 : X-band receiver parameters
11 : agc [dBm]
12 : downlink frequency [Hz]
13 : downlink frequency residual [Hz]
14 : total slipped cycles during count
15 : differential Doppler from Counts
A more detailed explanation of the parameters is given in section
TRK-2-15 of the JPL Document 820-13 [DSN820-13].
The total volume of validated SCE Doppler data in the archive is
given for both conjunctions in the following table.
conjunction # passes # hours # hours total MB total MB
total overlap (ASCII) (binary compressed)
C1
ingress 30 169.4 12.2 74.0 14.9
egress 34 201.0 14.4 87.8 17.5
total 64 370.4 26.6 161.8 32.4
C4
ingress 27 188.2 5.1 73.8 14.8
egress 24 194.0 7.5 76.0 15.2
total 51 382.2 12.6 149.8 30.0
----------------------------------------------------------------------
C1+C4 115 752.6 39.2 311.6 62.4
References
ASMARETAL1995
Asmar, S.W., R.G. Herrera, and T. Priest, Radio Science Handbook,
JPL D-7938 Volume 6, Jet Propulsion Laboratory, Pasadena, CA, 1995.
ASMAR&RENZETTI1993
Asmar, S.W., and N.A. Renzetti, The Deep Space Network as
an Instrument for Radio Science Research, Jet Propulsion
Laboratory Publication 80-93, Rev. 1, 15 April 1993.
BIRDETAL1992A
Bird, M.K., S.W. Asmar, J.P. Brenkle, P. Edenhofer, M. Paetzold,
and H. Volland, The coronal-sounding experiment,
Astron. Astrophys. Supp. Ser. 92, 425-430, 1992a.
BIRDETAL1992B
Bird, M.K., S.W. Asmar, J.P. Brenkle, P. Edenhofer, O. Funke,
M. Paetzold, and H. Volland, Ulysses radio occultation observations
of the Io plasma torus during the Jupiter encounter,
Science 257, 1531-1535, 1992b.
BIRDETAL1993
Bird, M.K., S.W. Asmar, P. Edenhofer, O. Funke, M. Paetzold,
and H. Volland, The structure of Jupiter's Io plasma torus
inferred from Ulysses radio occultation observations,
Planet. Space Sci. 41, 999-1010, 1993.
BIRDETAL1994
Bird, M.K., H. Volland, M. Paetzold, P. Edenhofer, S,W, Asmar,
and J.P. Brenkle, The coronal electron density distribution
determined from dual-frequency ranging measurements during
the 1991 solar conjunction of the {\sl Ulysses} spacecraft,
Astrophys. J. 426, 373-381, 1994.
BIRDETAL1996
Bird, M.K., M. Paetzold, M., P. Edenhofer, S.W. Asmar, and
T.P. McElrath, Coronal radio sounding with Ulysses: solar wind
electron density near 0.1 AU during the 1995 conjunction,
Astron. Astrophys. 316, 441-448, 1996.
DSN810-5
Deep Space Network / Flight Project Interface Design Book,
Document 810-5, Jet Propulsion Laboratory, Pasadena, CA.
DSN820-13
Deep Space Network System Requirements / Detailed
Interface Design, Document 820-13,
Jet Propulsion Laboratory, Pasadena, CA.
JANARDHANETAL1999
Janardhan, P., M.K. Bird, P. Edenhofer, R. Wohlmuth,
D. Plettemeier, S.W. Asmar, M. Paetzold, and J. Karl,
Coronal velocity measurements with Ulysses: Multi-link
correlation studies during two superior conjunctions,
Solar Phys., in press, 1999.
KARLETAL1997
Karl, J., M. Paetzold and M.K. Bird, Coronal radio sounding:
Non-Gaussian turbulence in the source regions of slow and
fast solar wind,
Geophys. Res. Lett. 24, 2881-2884, 1997.
PAETZOLD&BIRD1998
Paetzold, M., and M.K. Bird, Polar plumes and fine-scale coronal
structures - On the interpretation of coronal radio sounding data,
Geophys. Res. Lett. 25, 1845-1848, 1998.
PAETZOLDETAL1992
Paetzold, M., M.K. Bird, H. Volland, P. Edenhofer, S.W. Asmar,
and J.P. Brenkle, Coronal sounding with Ulysses: Preliminary results
from the first solar conjunction, in Solar Wind Seven, E. Marsch
and R. Schwenn (eds.), Pergamon Press, Oxford, 237-240, 1992.
PAETZOLDETAL1995
Paetzold, M., M.K. Bird, P. Edenhofer, S.W. Asmar, and
T.P. McElrath, Dual-frequency radio sounding of the solar corona
during the 1995 conjunction of the Ulysses spacecraft,
Geophys. Res. Lett. 22, 3313-3316, 1995.
PAETZOLDETAL1996
Paetzold, M., J. Karl, and M.K. Bird, Coronal radio sounding with
Ulysses: Dual-frequency phase spectra in coronal holes and streamers,
Astron. Astrophys. 316, 449-456, 1996.
PAETZOLDETAL1997
Paetzold, M., B.T. Tsurutani and M.K. Bird, An estimate of
large-scale solar wind density and velocity profiles in a
coronal hole and the coronal streamer belt,
J. Geophys. Res. 102, 24,151-24,160, 1997.
WOHLMUTHETAL1997
Wohlmuth, R., D. Plettemeier, P. Edenhofer, M.K. Bird, M. Paetzold
and S.W. Asmar, Measurement of the propagation speed of plasma
inhomogeneities in the solar corona using an uplink/downlink
correlation method,
Radio Sci. 32, 617-628, 1997.
WOO1996
Woo, R., Detection of low-latitude plumes in the outer
corona by Ulysses radio ranging measurements,
Astrophys. J. 464, L95-L98, 1996.
WOO&HABBAL1997
Woo, R., and S.R. Habbal, Extension of coronal structure into
interplanetary space,
Geophys. Res. Lett. 24, 1159-1162, 1997.
WOO&HABBAL1998
Woo, R., and S.R. Habbal, Comment on: "Polar plumes and fine-scale
coronal structures - On the interpretation of coronal radio
sounding data" by Paetzold and Bird,
Geophys. Res. Lett. 25, 1849-1850, 1998.
WOOETAL1995A
Woo, R., J.W. Armstrong, M.K. Bird and M. Paetzold,
Variation of fractional electron density fluctuations
inside 40 R_s observed by Ulysses ranging measurements,
Geophys. Res. Lett. 22, 329-332, 1995a.
WOOETAL1995B
Woo, R., J.W. Armstrong, M.K. Bird and M. Paetzold,
Fine-scale filamentary structure in coronal streamers,
Astrophys. J. 449, L91-L94, 1995b.
[ SCE Index ]