ISAS/JAXA Tracking station

Usuda Deep Space Center Diameter 10m –AE 44% expected Feed & Receiver –Ka-band Trx < 50K expected –cooled LNA –Tsys 140 K (fine condition)

Feed DIP TX- AMP U/C D/CLNA H-Maser DDS O/EE/O O/E LO O/EE/O U/C DDS LO D/C LO DEMPD FMT CLK GEN LO Mark5B Cooled VSOP-2 Ground System (Based on halca method) PC OBS Simulator CMD/MON Freq, Phase Controller 40.0 GHz 37.5 GHz 100MHz (±2MHz) 100MHz 1100MHz 100MHz (±2MHz) 500 MHz 5,900MHz 7,000MHz 26,000MHz 4,500MHz 7,000MHz 6,500MHz 100MHz 500MHz 100MHz10MHz VSI-H 1PPS 100MHz 400MHz Freq, Phase Control 26,000MHz Software Spectro- scope Ether Freq, Phase Control Network Ether 7,000MHz EtherGP-IB Antenna RoomOperation Center U/C 1,000MHz LO FIFO Carrier track

Feed DIP TX- AMP U/C D/CLNA H-Maser O/EE/O O/E LO O/EE/O LO D/CDEMPD FMT LO Mark5B Cooled VSOP-2 Ground System (w/o Doppler Comp.) PC OBS Simulator CMD/MON Freq, Phase Controller 40.0 GHz 37.5 GHz 100MHz 500 MHz 7,000MHz 26,000MHz 4,500MHz 7,000MHz 6,500MHz 100MHz 500MHz 100MHz10MHz VSI-H 1PPS 26,000MHz Software Spectro- scope Ether Network Ether 7,000MHz EtherGP-IB Antenna RoomOperation Center LO FIFO

Doppler compensation needed? Related Matters –Band mismatch –PLL Loop stress –Phase characteristics of onboard instruments –Correlator capability –System construction cost

Band mismatch Doppler shift: ~1MHz (f=40GHz, rr=7km/s) Band-mismatch: 126 MHz (128 – 2 MHz) Degradation of SNR ： 0.99 (√126/ 128)

PLL Loop stress Relation between Doppler rate and PLL : Natural angular frequency of second order loop(rad/sec) : Rate of change of angular frequency (rad/sec2) : Phase error of Phase Lock Loop, threshold ( ~12deg.)

Phase characteristics of instruments Phase fluctuation dφ by df : Easy estimation –H up (f)- H down (f)=2πfτ –Group delay characteristicsτ: ～ 1nsec –Phase fluctuation dφ ～ 0.36 deg (df~1MHz) Phase characteristics measurements needed before launch

Data Storage Storage Terminal with VSI –Mark5B (Haystack) –K5-VSI (NiCT) –Clock fluctuation compensated by FIFO? Corrlator interface –VLBA correlatorMark5 –ENV correlatorMark5 –EAVN* correlatorMark5, K5, VERA terminal *EAVN (East Asia VLBI Network)

East Asia VLBI Network Correlator Korea-Japan Joint VLBI Correlator (KJJVC) –KVN and NAOJ KVN, VERA, JVN, VSOP-2 Seoul 16 stations Data buffer Data rate –Max. 8 Gbps/st

Summary UDSC 10m antenna is expected to VSOP- 2 GTS Doppler compensation system depends on cost. Several VSI storages are available –Mark5B is better for operational easiness at three correlators.