研究者詳細 - 山田　寛喜

論文 - 山田　寛喜

分割表示 893 件中 141 - 160 件目／全件表示 >>

DOA Estimation of Multi-band Signals Using a Compressed Sensing Technique 査読

Terada, Tsubasa, Nishimura, Toshihiko, Ogawa, Yasutaka, Ohgane, Takeo, Yamada, Hiroyoshi

2014 INTERNATIONAL WORKSHOP ON ANTENNA TECHNOLOGY: "SMALL ANTENNAS, NOVEL EM STRUCTURES AND MATERIALS, AND APPLICATIONS" (IWAT) 359 - 362 2014年

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：IEEE

Much attention has been paid to direction of arrival (DOA) estimation using a compressed sensing technique. In our previous study, we have proposed a method to estimate DOAs of multi-band signals using an array antenna at a receiver. As a result, we have produced an improvement of the probability of correct estimation. Moreover, the method can deal with waves exceeding the degrees of freedom of the array. However, we have assumed that incident waves have multi-bands where complex amplitudes are the same. First, in this paper, we propose a method that allows the estimation of DOAs when only the phases at the bands are different using not the complex amplitudes but powers of the signals. Second, we extend the technique in such a way that it can estimate DOAs of the signals having different amplitudes among bands.

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X-BAND 30 CM RESOLUTION FULLY POLARIMETRIC SAR IMAGES OBTAINED BY Pi-SAR2 招待査読

Y. Yamaguchi, G. Singh, S. Kojima, M. Satake, M. Inami, S. Park, Y. Cui, H. Yamada, R. Sato

2014 IEEE INTERNATIONAL GEOSCIENCE AND REMOTE SENSING SYMPOSIUM (IGARSS) 2014年

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：IEEE

This paper presents very high resolution (30 cm) and fully polarimetric images acquired with a new airborne Polarimetric Interferometric Synthetic Aperture Radar 2 (Pi-SAR2) system operating at the X-band. Pi-SAR2 is a successive version of the former X-band Pi-SAR aiming at exploring the possibility of fully polarimetric SAR. In collaborative works among NICT and research institutions in Japan, data acquisition flights over Niigata have been carried out on August 25 and November 17, 2013. Some imaging results with interesting phenomena are shown using polarimetric scattering power decomposition.

DOI： 10.1109/IGARSS.2014.6946350

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DOA Estimation of Correlated Wideband Signals by using Multi-band EM Algorithm 査読

Yamada, Hiroyoshi, Shirai, Satoshi, Nishimura, Toshihiko, Ogawa, Yasutaka, Ohgane, Takeo, Yamaguchi, Yoshio

2014 USNC-URSI RADIO SCIENCE MEETING (JOINT WITH AP-S SYMPOSIUM) 205 - 205 2014年

A Study on Detecting Man-made Objects Using Correlation Coefficients in Circular Polarization Basis 査読

Motoki Masaka, Yoshio Yamaguchi, Hiroyoshi Yamada, Ryoichi Sato

2014 IEEE INTERNATIONAL WORKSHOP ON ELECTROMAGNETICS (IEEE IWEM): APPLICATIONS AND STUDENT INNOVATION COMPETITION 44 - 45 2014年

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：IEEE

This paper shows efficacy of an algorithm detecting man-made objects area by measuring and analyzing wave scattering from its models. The algorithm uses the co-polarized correlation coefficient in LR circularization basis and its normalized one, and switch these coefficients for detecting the man-made objects not only normally but also obliquely alignment to the radar illumination direction. For setting parameters in the algorithm appropriately, we carry out a polarimetric scattering measurement for man-made objects models in anechoic chamber.

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Wideband DOA Estimation Technique for Correlated Sources 査読

Hiroyoshi Yamada, Satoshi Shirai, Yoshio Yamaguchi

2014 INTERNATIONAL SYMPOSIUM ON ANTENNAS AND PROPAGATION (ISAP) 27 - 28 2014年

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：IEEE

Recently, researches on the wideband wireless system becomes important increasingly due to growth of the requirements on the high-speed broadband communications. Direction of arrival estimation of such a wideband sources with array also important for radio propagation estimation and/or surveillance. DOA estimation of wideband sources is one of the difficult problem because suitable element separation of the array essentially determined by the wavelength of the wave(s). In this report, we propose a new wideband DOA estimation technique that is available depending on the signal correlations.

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DOA Estimation of Wideband Signals Using Extended Virtual Array 招待査読

Hiroyoshi Yamada, Satoshi Shirai, Yoshio Yamaguchi

PROCEEDINGS OF 2014 3RD ASIA-PACIFIC CONFERENCE ON ANTENNAS AND PROPAGATION (APCAP 2014) 802 - 805 2014年

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：IEEE

Recently, researches on wideband wireless communications have been investigated intensively. With the progress of wideband wireless communications, DOA estimation technique for wideband incident waves has been also required. The history of high-resolution wideband DOA estimation started several decades ago. However its standard technique is not developed yet. In this report, we have proposed a new wideband DOA estimation technique using the Khatri-Rao matrix product. This method enables a wideband DOA estimation by using a simple conversion of sub-frequency band signals. In addition this technique realizes enhancement of the degrees-of-freedom of the array as well as high DOA resolution property. In this paper, performance of the proposed technique is reported by computer simulations.

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Human Motion Detection and Extraction by Using FM-CW Range-Doppler Radar 査読

Shinya Fukushima, Hiroyoshi Yamada, Hirokazu Kobayashi, Yoshio Yamaguchi

2014 INTERNATIONAL SYMPOSIUM ON ANTENNAS AND PROPAGATION (ISAP) 173 - 174 2014年

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：IEEE

Sensing technology using radio wave has been attracting attention for various applications such as office/home security and surveillance. Classification of human motion has been extensively studied in these applications. They often utilize micro-Doppler signature, or Doppler frequency signature occurred by human motion. In this paper, 4 type of range-Doppler signatures in human motion at a certain range are studied, and difference of the motions is confirmed experimentally. Moreover, extraction technique for range-Doppler signature with several moving humans are studied. Experimental results show that we can easily suppress the undesired target responses and extract the desired target response by using range-Doppler filtering scheme.

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Khatri-Rao変換を用いた広帯域信号DOA推定に関する検討査読

白井智士, 山田寛喜, 西村寿彦, 小川恭孝, 山口芳雄

電子情報通信学会技術研究報告 AP2013-131 ( 12 ) 35 - 40 2013年12月

周波数特性を有するマルチバンド信号の到来方向推定に関する検討査読

寺田翼, 西村寿彦, 小川恭孝, 大鐘武雄, 山田寛喜

電子情報通信学会技術研究報告 AP2013-116 ( 11 ) 93 - 98 2013年11月

屋内人物位置推定におけるSTAPの有効性に関する検討査読

佐藤, 山田,山口

2013年度電子情報通信学会信越支部大会 ( 4A-3 ) 2013年10月

MIMOセンサにおける相関係数の統計的性質に関する実験的検討査読

板橋, 山田,山口

2013年度電子情報通信学会信越支部大会 ( 4C-1 ) 2013年10月

Kinect を利用した自由走査式イメージングレーダシステムの検討査読

山田, 山田,山口

2013年度電子情報通信学会信越支部大会 ( 4B-1 ) 2013年10月

Khatri-Rao 変換を用いた広帯域信号DOA推定における周波数特性補正査読

白井, 山田,山口

2013年度電子情報通信学会信越支部大会 ( 4A-1 ) 2013年10月

高分解能海洋レーダにおける相関行列の対角平均化について査読

小沢,山田, 山口, 平野,伊藤

2013年度電子情報通信学会信越支部大会 ( 4C-2 ) 2013年10月

DOA推定におけるスパース信号再構成アルゴリズムの比較検討査読

龍川, 山田,山口

2013年度電子情報通信学会信越支部大会 ( 4A-2 ) 2013年10月

植生領域におけるPOLSAR画像散乱モデル分解法の特性比較査読

佐藤,渡邊, 山田,山口

2013年度電子情報通信学会信越支部大会 ( 4A-4 ) 2013年10月

Angular Resolution Improvement of Ocean Surface Current Radar Based on the Khatri-Rao Product Array Processing 査読

Hiroyoshi Yamada, Naoki Ozawa, Yoshio Yamaguchi, Keizo Hirano, Hiroyuki Ito

IEICE TRANSACTIONS ON COMMUNICATIONS E96B ( 10 ) 2469 - 2474 2013年10月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG

Ocean surface current radar is a Doppler radar to observe oceanographic information using the Bragg scattering resonance mechanism. In this paper, we consider angular resolution improvement of the radar. The radar employs an antenna array with FMICW operation, then it can resolve angular distribution by Digital Beam Forming (DBF) and distance by Fourier transform of the beat signal obtained by the FMICW radar. In order to obtain sufficient angular resolution, large array length or aperture with increasing the number of elements is needed, that is often difficult to realize in the HF/VHF ocean surface current radar. In this paper we propose to apply the Khatri-Rao (KR) product array processing to the radar. To verify effectiveness of the KR product array processing in angular resolution enhancement for the ocean surface current radar, we apply the KR product array to actual experimental data set of the radar, and show that the method is available to angular resolution enhancement and Doppler spectrum improvement.

DOI： 10.1587/transcom.E96.B.2469

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A Novel DOA Estimation Error Reduction Preprocessing Scheme of Correlated Waves for Khatri-Rao Product Extended-Array 査読

Satoshi Shirai, Hiroyoshi Yamada, Yoshio Yamaguchi

IEICE TRANSACTIONS ON COMMUNICATIONS E96B ( 10 ) 2475 - 2482 2013年10月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG

In this paper, we study on direction-of-arrival (DOA) estimation error reduction by Khatri-Rao (KR) product extended array in the presence of correlated waves. Recently, a simple array signal processing technique called KR product extended array has been proposed. By using the technique, degrees-of-freedom of an array can be easily increased. However, DOA estimation accuracy deteriorates when correlated or coherent waves arrive. Such highly correlated waves often arrive for radar application, hence error reduction technique has been desired. Therefore, in this paper, we propose a new method for error reduction preprocessing scheme by using N-th root of matrix. The N-th root of matrix has a similar effect to the spatial smoothing preprocessing for highly correlated signals. As a result, DOA estimation error due to signal correlation will be reduced. The optimal order of N depends on the data itself. In this paper, a simple iterative method to obtain adaptive N is also proposed. Computer simulation results are provided to show performance of the proposed method.

DOI： 10.1587/transcom.E96.B.2475

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広帯域信号を用いたDOA推定における推定可能到来波数の改善査読

白井智士, 山田寛喜, 山口芳雄

電子情報通信学会ソサイエティ大会 ( B-1-205 ) 2013年9月

Theoretical Study of Backscatter from Rice Paddy Using Discrete Scatterer Model 査読

M.Arii, H.Kitta, T.Watanabe, H.Yamada

Proc. Asia Pacific Synthetic Aperture Radar Conference (APSAR 2013) 2013年9月

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