IVS GM sekido NAVI

VLBI Observation for Spacecraft Navigation (NOZOMI) – Data Processing and Analysis Status Repot: 

VLBI Observation for Spacecraft Navigation (NOZOMI) – Data Processing and Analysis Status Repot M.Sekido, R.Ichikawa,H.Osaki, T.Kondo,Y.Koyama(CRL) M.Yoshikawa,T.Ohnishi(ISAS), W.Cannon, A.Novikov (SGL), M.Berube(NRCan), NOZOMI VLBI group(CRL,ISAS,NAOJ,GSI,…)

Spacecraft Navigation with VLBI: Motivation: 

Spacecraft Navigation with VLBI: Motivation Required for increased accuracy for future space missions: For landing, orbiting, & saving energy

NOZOMI’s Earth Swing-by : 

NOZOMI’s Earth Swing-by NOZOMI was launched in July 1998. Due to some troubles, new orbit plan with Earth swing-by was proposed. R&RR observations were difficult in some period

Slide4: 

Mizusawa (NAO) Kashima (CRL) Koganei (CRL) Usuda (ISAS) Yamaguchi (Yamaguchi Univ.) Gifu (Gifu Univ.) Kagoshima(ISAS) (uplink) Tomakomai (Hokkaido Univ.) Tsukuba (GSI) Algonquin SGL & NRCan Japanese and Canadian VLBI Stations participated in NOZOMI VLBI observations. ISAS,CRL,NAOJ, GSI,Gifu Univ, Yamaguchi Univ. Hokkaido Univ. SGL, NRCan supported.

For astrometry of S.C.Tasks to be done are: 

For astrometry of S.C. Tasks to be done are VLBI for Finite distance radio source A New VLBI delay Model corresponding to the CONSENSUS model. Narrow band width signal Group delay or Phase delay Delay Resolution: (nano/pico seconds) Ambiguity problem Data Processing and Analysis software IP-sampler boards recording to HD Software correlation & Analysis software

VLBI delay model for finite distance radio source: 

VLBI delay model for finite distance radio source VLBI for finite distance radio source Normal VLBI (Fukuhisma 1993 A&A)

VLBI delay model for finite distance radio source: 

VLBI delay model for finite distance radio source CONSENSUS MODEL (M.Eubanks 1991) Finite Distance VLBI MODEL (Sekido & Fukushima 2003)

Analysis Procedure: 

Analysis Procedure Compute a priori (delay, rate) (C) and partials We modified CALC9 for our use(finite VLBI). (Thanks to NASA/GSFC group for permission to use) Extracting Observable (tg, dtg/dt, tp)(O) with software correlator. Computing O-C and least square parameter estimation

Group Delay(Post-fit Residual): 

Group Delay(Post-fit Residual) Rate residual Delay Residual

Group Delay(Domestic Baselines): 

Orbit motion Group Delay (Domestic Baselines) 6/4(VLBI) 6/4(R&RR) May 27 June 4 Origin is Orbit on May 27, which was Determined by ISAS with R&RR Origin is Orbit on June 4.

Phase delay: 

Phase delay

Phase Delay Analysis: 

Phase Delay Analysis Post Fit Delay Residual (sec) 4 June 2003

The OD(ISAS) is correct?: 

The OD(ISAS) is correct? True delay rate is obtainable from Doppler data. Then, is XYZ(OD) really correct? Or remaining bugs in our analysis ?.

Summary: 

Summary NOZOMI VLBI observations were performed with domestic and intercontinental baselines. Finite VLBI delay model was derived. An analysis software is developed with that delay model based on CALC9. Preliminary astrometric SC coordinates were obtained with Group/Phase delay observables. Problem of inconsistency in the coordinates need to be solved. Solution with full baselines have to be obtained. Next step:SC Astrometry-> Orbit estimation

Space: 

Space Orbit of NOZOMI

Group Delay(Range signal): 

Group Delay (Range signal) Closure Observation mode = 2MHz, 2bit

Spacecraft Navigation with VLBI : Motivation: 

Spacecraft Navigation with VLBI : Motivation Required for increased accuracy for future space missions: For landing, orbiting, & saving energy JPL/NASA has been employed Japanese Space Agency (ISAS+NASDA=JAXA) NOZOMI(Japanese Mars Explorer) Needs to support orbit determination with VLBI. Mission as our own Project

Spacecraft Navigation: 

Spacecraft Navigation

Observation：IP-VLBI Sampler board: 

Observation：IP-VLBI Sampler board Sampling rate:40k-16MHz Quantization bit: 1-8bit 4ch/board 10MHz,1PPS inputs K5　VLBI　System