Papers by Toshimichi Otsubo
Earth, Planets and Space, 2016
The aim of this study is to find an effective way to expand the ground tracking network of satell... more The aim of this study is to find an effective way to expand the ground tracking network of satellite laser ranging on the assumption that a new station is added to the existing network. Realistic numbers of observations for a new station are numerically simulated, based on the actual data acquisition statistics of the existing stations. The estimated errors are compared between the cases with and without a new station after the covariance matrices are created from a simulation run that contains six-satellite-combined orbit determination. While a station placed in the southern hemisphere is found to be useful in general, it is revealed that the most effective place differs according to the geodetic parameter. The X and Y components of the geocenter and the sectoral terms of the Earth's gravity field are largely improved by a station in the polar regions. A middle latitude station best contributes to the tesseral gravity terms, and, to a lesser extent, a low latitude station best performs for the Z component of the geocenter and the zonal gravity terms.
Advances in Space Research
Earth, Planets and Space, 2016
Instrumentation and Measurement Ieee Transactions on, Apr 1, 1993
Page 1. CENTRE-OF-MASS CORRECTION ISSUES: TOWARD MM-RANGING ACCURACY Toshimichi Otsubo (1) and Gr... more Page 1. CENTRE-OF-MASS CORRECTION ISSUES: TOWARD MM-RANGING ACCURACY Toshimichi Otsubo (1) and Graham M Appleby (2) (1) Kashima Space Research Center, National Institute of Information and Communications Technology ...
ABSTRACT In a cooperation between several Japanese institutes the multi-technique space geodetic ... more ABSTRACT In a cooperation between several Japanese institutes the multi-technique space geodetic analysis software "c5++" has been developed over the last years. The software provides consistent geodetic and geophysical models which can be accessed by single technique space-geodetic applications or can be used to combine several techniques on the observation level. Satellite Laser Ranging (SLR) and Very Long Baseline Interferometry (VLBI) stand-alone applications have been realized in the last two years. With the introduction of an option to utilize local-tie information as well as the possibility to estimate common parameters (clock, troposphere, orbits) the software enables rigorous combination of space-geodetic techniques on the observation level. Moreover, the inclusion of GNSS as a third space-geodetic technique has increased the choice of analysis strategies tremendously. We are going to discuss the advantages and drawbacks of combining space-geodetic data on the observation level and we reveal bottlenecks, which need to be handled properly in order to make this approach work well. We are going to show how single-technique based solutions at station TIGO differ from rigorously combined estimates and how this affects the interpretation of the underlying geophysical signal, especially post-seismic ground movement. In addition, it will be studied whether additional information from geometry-only techniques, like VLBI, impacts parameters that are solely related to the Earth's gravity field. Moreover, it will be discussed how common parameters have to be estimated and where biases/offsets need to be taken into account. An outlook on the future use of combination on the observation-level and the challenges that come with this approach will conclude our presentation.
Surveys in Geophysics, Aug 31, 2001
Page 1. GLONASS LASER RANGING ACCURACY WITH SATELLITE SIGNATURE EFFECT TOSHIMICHI OTSUBO1, GRAHAM... more Page 1. GLONASS LASER RANGING ACCURACY WITH SATELLITE SIGNATURE EFFECT TOSHIMICHI OTSUBO1, GRAHAM M. APPLEBY2 and PHILIP GIBBS2 NERC Space Geodesy Facility, UK (on leave from Communications ...
Advances in Space Research, 2015
40Th Cospar Scientific Assembly Held 2 10 August 2014 in Moscow Russia Abstract B0 1 74 14, 2014
Conference Proceedings. 10th Anniversary. IMTC/94. Advanced Technologies in I & M. 1994 IEEE Instrumentation and Measurement Technolgy Conference (Cat. No.94CH3424-9), 1994
ABSTRACT
The large number of satellite laser range measurements made to the GLONASS satellites during the ... more The large number of satellite laser range measurements made to the GLONASS satellites during the IGEX-98 and continuing IGLOS campaigns, as well as continuing global SLR tracking of GPS-35 and -36, presents the opportunity to make detailed independent comparisons with published navigational orbits. We make the comparisons in two complementary ways; first we determine weeklong orbits from the global sets
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Papers by Toshimichi Otsubo