上海天文台 shanghai astronomical observatory 4th ivs general meeting spacecraft tracking with...
TRANSCRIPT
4th IVS General Meeting
上海天文台Shanghai Astronomical Observatory
Spacecraft Tracking with
Chinese VLBI Network
Xiuzhong Zhang and Chinese VLBI Network Team
Shanghai Astronomical
Observatory
Chinese Academy of Sciences
上海天文台Shanghai Astronomical Observatory
Outline
1. introduction
2. Configuration of tracking test system
3. Some test observation results
4. Plan of VLBI spacecraft tracking in China
上海天文台Shanghai Astronomical Observatory
VLBI system with highest resolution technique is used for astronomers in radio wave domain; e-VLBI has got rapid progress in the past 4-5 years; More and more computing power with a
single IC chip; With these characteristics, VLBI system
becomes to possible to make real time tracking for spacecraft orbiting application.
1. Introduction
上海天文台Shanghai Astronomical Observatory
Huygens VLBI tracking team (abbreviated)
JIVE ESA-ESTEC NASA-JPL NRAOI.M.Avruch C.. van’t Klooster S.Asmar W.BriskenH.Bignall J.-P.Lebreton W.Folkner F.GhigoA.Brunthaler R.A.Preston G.LangstonR.M.Campbell J.RomneyM.A.Garrett L.I.Gurvits, R.OerlemansS.V.Pogrebenko
ASTRON ATNF U Tasmania NICT (CRL)A.R.Foley J.Lovell G.Cimo T.Kondo
C.Phillips. S.Elingsen
U Bonn J. Reynolds B.ReidM.Bird R.Sault.
T.Tzioumis
NAO China Helsinki U ISAST.An (ShAO) A.Mujunen R.DodsonX.Hong (ShAO) J.RitakariS.Huang (ShAO)D.Jiang (ShAO)X.Liu (UAO)
12 institutes and international 12 institutes and international organizations in 7 countriesorganizations in 7 countries
上海天文台Shanghai Astronomical Observatory
Spacecraft TT&C Signal Characteristics
Narrow bandwidth
several hundred KHz
Relative strong signal to noise rate
Special signal spectrum
with special structure
The dynamic range of signal amplitude relative large
上海天文台Shanghai Astronomical Observatory
CVN started spacecraft tracking science 2001
Different orbit spacecraft have been observed with VLBI system. i.e. GEO, TC-1, TC-2, SMART-1, deep space probe
VLBI tracking of the Venus balloon
Many system equipment have been improved
Prepare to do the orbiting of CE-1
Study of spacecraft tracking method
Spacecraft tracking with VLBI in China
上海天文台Shanghai Astronomical Observatory
工艺设备——上海测站子系统(天线改造后)
Up: New S band feedback
Left : New S/X band feedback
上海天文台Shanghai Astronomical Observatory
Test Observations in March 17 – 20, 2005
SH(25m), UR(25m), KM(3m telescope)
CVN Disk Array recorder
S Band for TC-1, S/X Band for Radio Source8 MHz Bandwidth for TC-1 and Radio Sour
ce
Radio Source : 3C454.3, 3C84 for correct the difference of station clocks
上海天文台Shanghai Astronomical Observatory
Test observations in Mar. 17 – 20, 2005 with TC-1
Apogee : > 80000Km
上海天文台Shanghai Astronomical Observatory
Orbiting result with VLBI Resuduals delay: 1.5624m(mean), 12.4448m(RMS)
上海天文台Shanghai Astronomical Observatory
SMART-1 TT&C downlink signalRight Above : sheshan stationRight Down : Urumqi station
上海天文台Shanghai Astronomical Observatory
Observation of Smart-1 (SH – UR)
Sept. 22, 2004 UTC, the distance between Smart-1 and the earth is more than 280,000Km . Used 0.5 second data via FTP for fringe checking, with these data, the delay accuracy is 0.6ns and delay rate accuracy is 1.8ps/s.
上海天文台Shanghai Astronomical Observatory
Smart-1 orbiting with VLBI Observation
Observe time (UT) : March 20, 2005 10h30m 16h50m
Orbit of Smart-1 : polar orbit, apogee 2833Km , perigee 498Km , period 4.95 hours
station : Seshan ( 25m ), Nanshan ( 25m ), Kunming ( 3m )。
Frequetion of carrie wave : 2235.10 MHz
Observe frequency : 2230.992238.99 MHz
Bandwidth : 8.0 MHz 。Radio source : 3C84 , 4C39.25 , 3C279 。MK5A recorder, 16 Mbps ,Data processing : Shanghai VLBI data processing center
Integration time : 4s
上海天文台Shanghai Astronomical Observatory
Smart-1 S Band (2.2GHz) downlink Signal
dB
dB
MHz
MHz
Wide Band mode
Narrow Band mode
上海天文台Shanghai Astronomical Observatory
The compare results of delay and delay rate between
VLBI observe and ESA Smart-1 reconstruction orbit
Resuduals Delay Resuduals delay rate
SH - UR
KM - SH
KM - UR
SH - UR
KM - SH
KM - UR
上海天文台Shanghai Astronomical Observatory
Future Plans
Develop and create a 4 stations VLBI network for astronomy and spacecraft tracking
Prepare to do the near real time orbit tracking of CE-1 (Chinese lunar project, will be launched in 2007)
Study the method of Deep space spacecraft tracking