Session Notes for rd1409 (OCEL03) - prepared by Ruediger Haas
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PURPOSE AND GENERAL NOTES
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===> OCEL - Observations of the Chang'E-3 lander with VLBI <===
This information is distributed via email to
Badary: Elena Skurikhina <sea@ipa.nw.ru>
Andrey G. Mikhailov <agm@ipa.nw.ru>
HartRAO: Jonathan Quick <jon@hartrao.ac.za>
Marisa Nickola <marisa@hartrao.ac.za>
Hobart: James Lovell <Jim.Lovell@utas.edu.au>
Lucia Plank <Lucia.Plank@utas.edu.au>
AuScope Operations <auscope-operations@postoffice.utas.edu.au>
Matera: Giovanni Nettis <vlbi@hp835.mt.asi.it>
Colucci Giuseppe <giuseppe.colucci@e-geos.it>
Matera vlbi <vlbi@hp835.mt.asi.it>
Ny-AAlesund: Moritz Sieber <moritz.sieber@kartverket.no>
VLBI Ny-lesund <vlbi@kartverket.no>
Shanghai: Xia Bo <bxia@shao.ac.cn>
Wettzell: Christian Pltz <ploetz@fs.wettzell.de>
Alexander Neidhardt <neidhardt@fs.wettzell.de>
RT-20m Wettzell <vlbi@fs.wettzell.de>
Urumqi: Wengjun Yan <yangwj@xao.ac.cn>
Xiang Liu <liux@xao.ac.cn>
Zelenchukskaya: Elena Skurikhina <sea@ipa.nw.ru>
Andrey G. Mikhailov <agm@ipa.nw.ru>
NASA/NVI: "Behrend, Dirk (GSFC-698.0)[NVI INC]" <dirk.behrend-1@nasa.gov>
"Cynthia C. Thomas" <Cynthia.C.Thomas@nasa.gov>
Ed Himwich <Ed.Himwich@nasa.gov>
UBonn: Axel Nothnagel <nothnagel@uni-bonn.de>
Alessandra Bertarini <abertari@mpifr-bonn.mpg.de>
Laura la Porta <laporta@mpifr-bonn.mpg.de>
BAAC: Tang Geshi <tanggeshi@bacc.org.cn>
Onsala: Rdiger Haas <rudiger.haas@chalmers.se>
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a) Background:
--------------
Tang Geshi and several co-PIs proposed in May 2014 to observe the Chinese Lunar Lander
Chang'E-3 with VLBI. This proposal was accepted by the IVS PC and a series of
RD-sessions was allocated for this purpose.
The scheduling is done by R. Haas (Chalmers University of Technology, Sweden),
the Lunar Lander apriori positions are provided by Tang Geshi (BAAC, China),
the primary correlation will be done by the Bonn correlator and special correlation
issues will be looked into by the correlators at BAAC (China) and Onsala (Sweden).
The data will be analyzed by the proposing consortium (PIs), and the data have a
one year data hold.
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b) Schedule:
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The 3rd OCEL-session is on October 7/8 when the Chang'E-3 lander will be actively
sending on several X-band channels, among them a data channel and several
DOR tones. However, the lander will only be active during parts of the 24 h session.
During the active period of the lander, alternating geodetic and phase-referencing
observations will be performed, in intervals of 30 min each.
The station network consists of 9 stations:
Badary, HartRAO, Hobart26, Matera, Nyales20, Seshan25, Urumqi, Wettzell, Zelenchk
This time there are a number of constraints, though:
- The lunar lander is switched off October 7, 19:30-20:00, to avoid overheating.
- The lunar lander is switched off October 7, 23:38, since the moon sets for the Chinese stations.
- The lunar lander will be switched on again on October 8, 09:42 when the moon rises for the Chinese stations.
- During the lunar eclipse on October 8, 08:49-12:49, the lunar lander will send only the DOR signal.
- Seshan25 sleeves the session on October 8, 08:30, due to an EVN session.
The schedule looks as follows:
17:30-18:00 GEO
18:00-18:30 PHAREF LL/RS: 0119+115 and 0048-097
18:30-19:00 GEO
19:00-19:30 PHAREF LL/RS: 2318+049
19:30-20:00 GEO
20:00-20:30 PHAREF LL/RS: 0119+115 and 2355-106
20:30-21:00 GEO
21:00-21:30 PHAREF LL/RS: 0119+115 and 2355-106
21:30-22:00 GEO
22:00-22:30 PHAREF LL/RS: 0119+115 and 2318+049
22:30-23:00 GEO
23:00-23:30 PHAREF LL/RS: 0119+115 and 0048-097
23:30-12:00 GEO
12:00-12:30 PHAREF LL/RS: 2318+049 and 2355-106
12:30-13:00 GEO
13:00-13:30 PHAREF LL/RS: 2318+049
13:30-14:00 GEO
14:00-14:30 PHAREF LL/RS: 2318+049 and 2355-106
14:30-15:00 GEO
15:00-15:30 PHAREF LL/RS: 2318+049 and 2355-106
15:30-16:00 GEO
16:00-16:30 PHAREF LL/RS: 2318+049 and 2355-106
16:30-17:00 GEO
17:00-17:30 PHAREF LL/RS: 2318+049 and 0119+115
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c) Preparation at the stations:
-------------------------------
The schedule files were provided in form of individual vex-files. The files are individual per
station since the lunar lander has slightly different apriori ra/dec coordinates as seen
from the different participating stations, since the Moon is in the near field. The vex files are
rd1409_bd_new.vex
rd1409_ho_new.vex
rd1409_ht_new.vex
rd1409_ma_new.vex
rd1409_ny_new.vex
rd1409_sh_new.vex
rd1409_ur_new.vex
rd1409_wz_new.vex
rd1409_zc_new.vex
The stations should use their individual vex file, copy it to the name rd1409.vex and then drudg it
in order to produce snap-file and procedure-file. The FS version 9.11.6 appears necessary. There
might though be some complaints by drudg, however, the resulting snp and prc-files should be correct
and working.
Stations that do not have FS 9.11.6 can get assistance by Ed Himwich who can provide them
with the necessary *.snp and *.prc files.
There are three setups in the session, setup01, setup02 and setup03. The first setup is a standard
setup usually used for narrow-band T2-sessions, while the second setup and third setups are special
lunar lander setups. For the latter two, the X-band frequencies are modified in order to correspond
to the lunar lander sending frequencies. There are setup02 and setup03 in order to make it possible
for stations that do not have automatic gain control, to use special and individual attenuation
when observing the lunar lander and natural radio sources in phase-referencing mode.
All lunar lander center frequencies are between 8450 MHz and 8496 MH, with bandwidth of 2 to 5 MHz.
The data channel with center frequency 8496 MHz is rather strong with an EIRP of about 16 W.
The DOR channels are located at 8470 MHz and tones at +/- 19.2 MHz and +/- 3.85 MHz and these channels
have an EIRP of about 1 W. Due to the rather strong signals, the received signal strength is on the
order of 10-30 dB stronger than normal natural radio sources. Thus, additional attenuation has to be
implemented in the lunar lander setup. Stations with Mark4 racks should prepare to add on the order
of 10-30 dB, and then monitor and adapt the attenuation correspondingly. This can be done in the beginning
of the experiment when the first observations of the lunar lander signals are performed.
The frequency distribution for the lunar lander observations is as follows:
BBC 1 8466.99 MHz (DOR central tone - 1 Mhz, USP)
BBC 2 8492.99 MHz (Data channel - 1 Mhz, USP)
BBC 3 8448.99 MHz (DOR - 19.2 MHz, USP)
BBC 4 8463.99 MHz (DOR - 3.85 MHz, USP)
BBC 5 8467.99 MHz (DOR central tone, USP)
BBC 6 8471.99 MHz (DOR + 3.85 MHz, USP)
BBC 7 8486.99 MHz (DOR + 19.2 MHz, USP)
BBC 8 8497.99 MHz (Data channel, LSP)
An approximate summary of the session is given below. The amount of data to be recorded is just less
than 1 TB per station. The stations should transfer (e- or ship) the data to the Bonn correlator
after the session is done.
SKED Summary from file /home/mk5_2014/sched/ocel03.skd for experiment OCEL03
(all scans with at least one subnet station)
Calculating rise/set times:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40
41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78... done.
Average number of obs. per baseline per source(normalized by up-time) = 8.0
Min = 0.0 Max = 134.6 (Baseline Bd-Ur on OCEL.03 ) RMS = 15.1
Total time: 1439 minutes ( 24.0 hours).
Key: Ny=NYALES20 Sh=SESHAN25 Bd=BADARY Zc=ZELENCHK Ma=MATERA
Ur=URUMQI Wz=WETTZELL Ht=HART15M Ho=HOBART26
Ny Sh Bd Zc Ma Ur Wz Ht Ho Avg
% obs. time: 43 25 27 23 45 49 35 32 25 34
% cal. time: 4 3 5 5 4 4 5 4 3 4
% slew time: 18 17 51 52 26 27 11 18 37 29
% idle time: 34 54 15 19 24 19 48 45 33 33
total # scans: 365 226 454 439 379 381 414 372 298 369
# scans/hour : 15 9 19 18 16 16 17 16 12 15
Avg scan (sec): 101 97 51 45 102 110 74 75 73 80
# data tracks: 16 16 16 16 16 16 16 16 16
# Mk5 tracks: 16 16 16 16 16 16 16 16 16
Total TBytes: 0.7 0.4 0.4 0.4 0.7 0.8 0.6 0.5 0.4 0.5
Total TB(M5): 0.6 0.3 0.4 0.3 0.6 0.7 0.5 0.4 0.3 0.5
# OF OBSERVATIONS BY BASELINE
| Ny Sh Bd Zc Ma Ur Wz Ht Ho Total
-------------------------------------------------------
Ny| 151 262 271 268 242 307 119 34 1654
Sh| 190 138 125 169 136 60 74 1043
Bd| 308 207 344 246 114 124 1795
Zc| 271 258 310 187 51 1794
Ma| 214 340 176 23 1624
Ur| 229 131 114 1701
Wz| 168 20 1756
Ht| 147 1102
Ho| 587
Number of 2-station scans: 306
Number of 3-station scans: 178
Number of 4-station scans: 98
Number of 5-station scans: 56
Number of 6-station scans: 67
Number of 7-station scans: 107
Number of 8-station scans: 37
Number of 9-station scans: 7
Total number of scans: 856
Total number of obs: 6528
Total integrated obs-time: 450885
Average obs-time: 69.1
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