http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Tsujii, Toshiaki,Fujiwara, Takeshi,Kubota, Tetsunari,Satirapod, Chalermchon,Supnithi, Pornchai,Tsugawa, Takuya,Lee, Hungkyu Korean Society of Surveying 2012 한국측량학회지 Vol.30 No.6
Ionospheric anomaly is one of the major error sources which deteriorate the GNSS performance. In the equatorial region, effects of the ionospheric plasma bubbles are of great interest because they are pretty common phenomena, especially in the period of the high solar activity. In order to evaluate the GNSS performance under circumstance of the bubbles, an ionospheric scintillation monitor has been developed and installed in Bangkok, Thailand. Furthermore, a model simulating the ionospheric delay and scintillation due to the bubbles has been developed. Based on these developments, the effects of the simulated plasma bubbles are analyzed and their agreement with the real observation is demonstrated. An availability degradation of the GPS ground based augmentation system (GBAS) caused by the bubbles is exampled in details. Finally, an integrated GPS/INS approach based on the Doppler frequency is proposed to remedy the deterioration.
Measuring Multipath Error of a Pseudo Quasi-Zenith Satellite
Toshiaki Tsujii,Hiroshi Tomita,Yoshinori Okuno,Ivan Petrovski,Masahiro Asako,Kazuki Okano 한국항해항만학회 2006 한국항해항만학회 학술대회논문집 Vol.2 No.-
Japan has been investigating a new satellite based positioning system called Quasi-Zenith Satellite System (QZSS). Since the improvement of positioning availability in urban area is one of the most important advantages of the QZSS, multipath mitigation is a key factor for the QZSS positioning system. Therefore, Japan Aerospace Exploration Agency (JAXA) and GNSS Inc. have commenced the R&D of a pseudolite, which transmits the next-generation signal such as BOC(1,1), in order to evaluate the effect of multipath on the new signal. A prototype BOC pseudolite was developed in 2005, and ground tests showed a capability of generating proper pseudorange. Also, preliminary flight experiments using a pseudo quasi-zenith satellite, a helicopter on which the pseudolite is installed, were conducted in early 2006, and the BOC-type correlation function was monitored in real time.
Development of INS-aided GPS Tracking Loop and Preliminary Flight Test
Toshiaki Tsujii,Takeshi Fujiwara,Yoshimitsu Suganuma,Hiroshi Tomita,Ivan Petrovski 제어로봇시스템학회 2009 제어로봇시스템학회 국제학술대회 논문집 Vol.2009 No.8
Robust tracking of GNSS signal in a harsh environment such as a severe ionospheric scintillation is achallenge for civil aviation. The use of inertial sensor would improve the tracking performance since the Doppler frequency caused by aircraft dynamics could be compensated by the inertial measurements. In order to evaluate such an aiding, an INS aided GPS tracking loop was developed by using a software receiver, and a preliminary flight test was conducted. Off-line analyses showed a reduced carrier phase error and a possible reduction of noise band width in tracking loop, which would result in positioning accuracy improvement.
Improvement of a Low Cost MEMS-based GPS/INS, Micro-GAIA
Takeshi Fujiwara,Toshiaki Tsujii,Hiroshi Tomita,Masatoshi Harigae 한국항해항만학회 2006 한국항해항만학회 학술대회논문집 Vol.1 No.-
Recently, inertial sensors like gyros and accelerometers have been quite miniaturized by Micro Electro-Mechanical Systems (MEMS) technology. JAXA is developing a MEMS-based GPS/INS hybrid navigation system named Micro-GAIA. The navigation performance of Micro-GAIA was evaluated through off-line analysis by using flight test data. The estimation errors of the roll, pitch, and azimuth were 0.03°, 0.05°, and 0.33° (1ο), respectively. The horizontal position errors after 60-second GPS outages were reduced to 25m CEP. The attitude errors and position errors are nearly half of ones reported previously[2]. Furthermore, using the adaptive Kalman filters, the robustness against the uncertainty of the measurement noise was improved. Comparing the innovation-based and residual-based adaptive Kalman filters, it was confirmed that the latter is robuster than the former.