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ASTRO-G Ground Tracking Station Plan Y.Murata (JAXA). Start from HALCA design Functions Uplink reference signal Data demodulation Data recording Telemetry Data Extraction Doppler measurement. Signal from Astronomical Objects. VSOP tracking station. LNA. ANT. - PowerPoint PPT Presentation
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ASTRO-GGround Tracking Station Plan
Y.Murata (JAXA)• Start from HALCA design
• Functions– Uplink reference signal– Data demodulation– Data recording– Telemetry Data Extraction – Doppler measurement
Signal from Astronomical Objects
Orbit Prediction
VSOP tracking station
H maser
Uplink Freq. Cntl.
Downlink Freq. Cntl.
D/C
LNA ANT
A/D
MODTX
HGA
RXLOCAL
VLBI data
SYNC (4byte)
DEMOD
2way phase residual
2way Doppler
TLM Header (8byte)
VLBI data
32M clock
1PPS gen.
1 PPS
VLBI Recording
TLM ground
15.3 GH z+Doppler CorrectionCW
14.2 GH zQPSK
1 Frame (10,000 byte / 5 ms)
Difference from HALCA tracking station
• Frequencies– Up: 40 GHz + Doppler Compensation(?)– Down: 37 – 38 GHz
• Data demodulation– 1 Gbps QPSK
• Data recording– Giga-bit recording, VSI (VERA, Mark 5, K5/VSI, …)
• Telemetry Data Extraction – Realtime / near realtime
• Doppler measurement• No Phase cal pulse
Number of Tracking stations
Number of Tracking stations
Tra
ckin
g ti
me
(%)
FAKESAT for VSOP-2
D.W.MurphyLinux/Cygwin
○Kaj Wiik,R.Dodson
Visibility of HALCA from tracking stations (ah=21,000km, i=31)
ω= 270
ω= 0
ω= 90
ω= 180
SANTMALIHARTUSUDTIDBMADRGOLDGBANK
NorthApogee
SouthApogee
Visibility of ASTRO-G from tracking stations (ah=25,000km)
ω= 270
ω= 0
ω= 90
ω= 180
SANTMALIHARTUSUDTIDBMADRGOLDGBANK
Visibility of ASTRO-G from tracking stations (ah=36,000km, i=28)
ω= 270
ω= 0
ω= 90
ω= 180
SANTMALIHARTUSUDTIDBMADRGOLDGBANK
Tracking station coverage requirements
• 3-4 tracking stations
• Uniform Longitude coverage
• Low Latitude is better