International VLBI tracking of SELENE N.Kawano, H.Hanada and K.Matsumoto NAOJ.
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International VLBI track ing of SELENE N.Kawano, H.Hanada and K.Matsum oto NAOJ
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Transcript of International VLBI tracking of SELENE N.Kawano, H.Hanada and K.Matsumoto NAOJ.
International VLBI tracking of SELENE
N.Kawano, H.Hanada and K.MatsumotoNAOJ
Main Sat.
V-star
R-starConcept of SELENE
By T. Iwata
( JAXA)
VLBI satellite (Vstar)
Solar Cell
Spin Stabilizer
Co-linear antenna
Existence of core ? Internal structure ?
Given by Gusev and Kawano
RSAT/VRAD
Relay satellite100km×2400km
Lunar orbiter100km±25km
JAXA/ISAS UDSC
JAXA new GN VRAD satellite100km×800km
radio source
transponder
transponder
radio source
NAOJ VERA foreign sites
Quasar
Gravity field of lunar limb (VRAD) far-side (RSAT)
TLM/CMD
From T.iwata
Doppler data coverage of main satellite
●2-way Doppler●4-way Doppler
Near-sideFar-side
By K.Matsumoto
VLBI obs. is effective in “Face-on”
Edge-on
Face-on
Gravity
Line of sight
Improvement by VLBI
Spherical harmonics
By Rstar. By VLBI
VERA Network for SELENE
Baseline~2000km
0 1 day
Sep. 2007 Aug.2008
0 30 days
8 hours
Nominal VLBI observation for SELENE
Regular obs.
~12days
~12days/month x 12
Total: ~1200 hours
El>15deg.
International VLBI Network
15 20 25 30 35 40
10
20
30
40
50
60
70
80
15 20 25 30 35 40
10
20
30
40
50
60
70
80
15 20 25 30 35 40
10
20
30
40
50
60
70
80
25 30
10
20
30
40
50
60
70
80
25 30
10
20
30
40
50
60
70
80
25 30
10
20
30
40
50
60
70
80
MizusawaUrumqiWettzell
Time (day) From August 1215 20 25 30 35 40
Ele
vati
on (
deg)
Time (day)
80
60
40
20
25 3027.5
0 1 day
0 4 days
Sep. 2007 Aug.2008
0 30 days
4 hours x4
3~4 days x 2
4 hours
1 month x 2 , “Face-on”
Intensive international VLBI observation
Extended obs.
~12days
~12days/month x 2
Total: 64 hours Total: ~100 hours
Core obs. Extended Obs.
Center frequency 2212 MHz 2218 MHz 2287 MHz 8456 MHz
Band width CW CW CW CW
Sample rate 200 ksps 200 ksps 200 ksps 200 ksps
Recording Hard disc
EIRP 24 mW 24 mW 24 mW 250 mW(Rstar)
38 mW(Vstar)
Polarization RHCP RHCP RHCP RHCP
Specifications of signals from Vstar and Rstar
Orbits of three satellites Main orbiter Perilune Apolune Inclination Period
Main orbiter 100 km 100 km 90 deg. ~120 min.
Vstar 100 km 800km 90 deg. ~153 min.
Rstar 100 km 2400 km 90 deg. ~240 min.
Thank you for your attention.
