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Ongoing activities on Delta-DOR cooperation between JAXA and other agencies. Hiroshi Takeuchi (JAXA/ISAS). Ongoing activities with JPL. Raw-data format ICDs were exchanged between JAXA (K5 format) and JPL (VSR format).
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Ongoing activities on Delta-DOR cooperation between JAXA and other agencies Hiroshi Takeuchi (JAXA/ISAS)
Ongoing activities with JPL • Raw-data format ICDs were exchanged between JAXA (K5 format) and JPL (VSR format). • While the analytic representation (I,Q) is used in the VSR format, real-valued signals are used in the K5 format. • VSR to K5 translator is completed. • K5 to VSR translator is almost completed, but definitions of some parameters in the VSR data record header should be confirmed to complete it.
HAYABUSA Delta-DOR experiment between JAXA and JPL (March 7,2007) Usuda Goldstone Canberra • JPL have supported the OD of Japanese Hayabusa spacecraft during critical phases from its launch. • JAXA Usuda 64-m antenna joined a Delta-DOR session performed by JPL using the baseline between Goldstone and Canberra. • Raw data recorded at DSN stations were sent to JAXA.
Detected cross-correlation peak between Canberra 70m(DSN) and Usuda 64m(JAXA) • DSN VSR data was translated to K5 format. • K5 software correlator was used in order to calculate the delay for the quasar. • Obtained S/N seems to be reasonable value. • S/C delay measurement processes should be clearly defined.
Ongoing activities with ESA • An agreement for the formalisation of cooperation on delta-DOR hasbeen reached on the ESA-JAXA Meeting in June 2006 • Agreement:Both agencies should transform the raw data from each own format to the following Mark5 format. • Number of channels: 8 • Quantization: 2 bits • Data rate: 4 MS/s • BW: 2 MHz per channel • Tracks fixed (same signal in each track, no fan-in, fan-out modes active)
Current status and proposal for next step • JAXA had already developed K5–Mark5 translator, which had been operationally used in international geodetic VLBI sessions. • We can go to the next steps if the development of Mark5 - ESA translator is completed by ESA. • If the development of the ESA to Mark5 translator is not going smoothly, we propose the use of the VSR format as a standard data-exchange format between us.
Other activities with international VLBI groups • Cooperating with Japanese VLBI groups such as NICT,NAOJ,GSI for the use of ‘phase delay’ for Hayabusa spacecraft. • Cooperation with JIVE (Joint Institute for VLBI in Europe) for the POD for the Huygens descent by means of phase referencing technique. → Should we define the use of ‘phase delay’ in the green book for future expansion? • Same Beam Interferometry using MMO and MPO in BepiColombo mission is proposed from JIVE and SHAO (Shanghai observatory) to measure the gravity field of Mercury.
SELENE: Same Beam Interferometry • Launched on September 14, 2007.Now on the transfer orbit to the Moon. • VLBI and 4-way Doppler will play important role for the measurement of lunar gravity. • VLBI experiments will be performed between Japanese VLBI stations (NAOJ), Hobart(Australia), Wetzell(Germany) and Urumqi(China). Kawano(NAOJ) et al.