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Author

Tetsuji Uebo

Other affiliations: University of Tokushima
Bio: Tetsuji Uebo is an academic researcher from NEC. The author has contributed to research in topics: Standing wave & Radar. The author has an hindex of 5, co-authored 11 publications receiving 102 citations. Previous affiliations of Tetsuji Uebo include University of Tokushima.

Papers
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Journal ArticleDOI
TL;DR: This work proposes a new method for measuring distances down to zero meters without expanding the frequency range using an analytic signal, which is a complex sinusoidal signal obtained by observing the standing wave with multiple detectors.
Abstract: Various types of radars have been developed and used until now-such as Pulse, FM-CW. and Spread Spectrum. Additionally, we have proposed another type of radar which measures distances by using standing wave. We have named it as Standing Wave Radar. It has a shorter minimum detectable range and higher accuracy compared to other types. However, the radar can not measure distances down to zero meters like other types of radars. Minimum detectable range of the standing wave radar depends on a usable frequency range. A wider frequency range is required if we need to measure shorter distances. Consequently, we propose a new method for measuring distances down to zero meters without expanding the frequency range. We use an analytic signal, which is a complex sinusoidal signal. The signal is obtained by observing the standing wave with multiple detectors. We calculate distances by Fourier transform of the analytic signal. Moreover, we verify the validity of our method by simulations based on numerical calculation. The results show that it is possible to measure distances down to zero meters. In our method, measurement errors are caused by deviations of position and gain of the detectors. They are around 10cm at the largest if the gain deviations are up to ±1% and the position deviations are up to ±6% of the spacing between the detectors. Prevalent radars still have a common defect that they can not measure distances from zero to several meters. We expect that the defect will be eliminated by putting our method into practical use.

29 citations

Patent
04 Jun 2003
TL;DR: In this article, the phase difference of the two radar image functions zero-crosses and the amplitude of the radar image function becomes maximum is measured with a high resolution, and the zero cross point is a zero crosspoint of a linear function and can be identified with high resolution.
Abstract: A distance can be measured with a high resolution. A frequency controller (7) controls a voltage control oscillator (2) so as to change a signal source frequency f in a range containing two central frequencies f1 and f2 and transmits it as a progressive wave from an antenna (4) to a target (5). A reflected wave reflected by the target (5) and the progressive wave interfere each other and form a standing wave. A power detector (6) detects power corresponding to the amplitude of the standing wave and performs Fourier transform based on the two central frequencies f1 and f2 in Fourier transform means (11, 12), respectively, thereby calculating radar image functions P1(x), P2(x). The distance d to the target (5) satisfies the conditions that the phase difference of the two radar image functions zero-crosses and the amplitude of the radar image functions becomes maximum. The zero cross point of the phase difference is a zero cross point of a linear function and can be identified with a high resolution.

25 citations

Journal ArticleDOI
TL;DR: In this paper, the authors proposed a method of realization for radar using a standing wave that can measure a moving target within 2 m at a speed of 0 km/h to 100km/h in simulations, within the specification of low power radio equipment to detect moving objects at 24 GHz with a narrow bandwidth of 76 MHz.
Abstract: For automobile safety, supplemental equipment such as seat belts and air bags is used. These devices are activated after an accident. In contrast, from the point of view of accident prevention, automotive radar has been developed for collision avoidance. Presently, typical radars are the frequency-modulated type and the pulse-modulated type. It is known that measurement of an object over short range is difficult with these types of radar. Here, we propose a method of realization for radar using a standing wave that can measure a moving target within 2 m at a speed of 0 km/h to 100 km/h in simulations, within the specification of low-power radio equipment to detect moving objects at 24 GHz with a narrow bandwidth of 76 MHz. This radar is not subject to the problems of FMCW radar such as leakage of the transmitted signal and false targets due to nonlinearity of the mixer. © 2006 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 89(5): 52–60, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.20165

17 citations

Proceedings ArticleDOI
25 Jul 2004
TL;DR: In this article, the authors proposed a radar using standing wave, which does not use a time delay like usual radars but uses the amplitude of the standing wave instead of using the time delay.
Abstract: In this paper, we propose a radar using standing wave, and describe the measurement principle and experiment results. This radar does not use a time delay like usual radars but uses the amplitude of the standing wave. As a result of experiments, this radar could measure the distance and velocity of a moving target using bandwidth of only 76 MHz permitted by the specification of low-power radio equipment to detect moving objects (24 GHz band). The bandwidth of the radar is narrower than that of a millimeter wave radar.

10 citations

Patent
20 Apr 2004
TL;DR: In this paper, a distance measurement system sends an electromagnetic wave toward the measurement object as a traveling wave while changing a frequency thereof, and the measured object reflects the traveling wave to produce a reflected wave.
Abstract: A distance measuring method simultaneously measures a distance between a distance measurement system ( 10 A) and a measurement object (M), and a relative speed therebetween. In the method, the distance measurement system sends an electromagnetic wave toward the measurement object as a traveling wave while changing a frequency thereof. The measurement object reflects the traveling wave to produce a reflected wave. The traveling wave and the reflected wave interfere with each other to produce a standing wave. The distance measurement system detects the amplitude of the standing wave and produces an amplitude signal representing the amplitude of the standing wave. Based on the produced amplitude signal, the distance measuring system derives the distance and the relative speed between the distance measurement system and the measurement object.

6 citations


Cited by
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Patent
14 Jul 2006
TL;DR: In this article, a transmission unit emits an electromagnetic wave having the same frequency f as an output signal from a sending unit in a direction of a measurement axis, and a detecting unit performs synchronous detection on a reflected wave detected by a directional coupler by an in-phase signal and a quadrature signal of the transmission signal.
Abstract: A transmission unit emits an electromagnetic wave having the same frequency f as an output signal from a sending unit in a direction of a measurement axis. A detecting unit performs synchronous detection on a reflected wave detected by a directional coupler by an in-phase signal and a quadrature signal of the transmission signal, and by extracting DC component from the detection signal, detects the in-phase component and quadrature component of the reflected wave. An analysis signal generating unit mixes the in-phase component and quadrature component of the reflected wave and signals having periodicity corresponding to a prescribed distance, and using only one of the resulting side bands, generates an analysis signal. Fourier transform unit finds distance to the object of measurement from a profile obtained by Fourier transform of the analysis signal.

31 citations

Journal ArticleDOI
TL;DR: This paper fundamentally examines the distance estimation method in which acoustical standing wave is used in the research field of microwave radar and focuses its attention on audible sound.
Abstract: In the research field of microwave radar, a range finding method based on standing wave is known to be effective for measuring short distances. In this paper, we focus our attention on audible sound and fundamentally examine the distance estimation method in which acoustical standing wave is used.

26 citations

Patent
25 Aug 2006
TL;DR: In this paper, the authors provided a distance measuring device and a distance measurement method characterized by simple configuration, capability of measuring a near distance, and a small measurement error, like a measurement device using a standing wave.
Abstract: There are provided a distance measuring device and a distance measuring method characterized by “simple configuration”, “capability of measuring a near distance”, and “a small measurement error” like a distance measuring device using a standing wave. The distance measuring device includes a signal source (1) for outputting a signal having a plurality of different frequency components within a particular bandwidth, a transmission unit (2) for transmitting a signal as an undulation, s mixed wave detection unit (3) for detecting a mixed wave VC obtained by mixing a progressive wave VT transmitted and a reflected wave VRk of the progressive wave VT reflected by a measurement object (6), a frequency component analysis unit (4) for analyzing the frequency component of the mixed wave VC detected, and a distance calculation unit (5) for obtaining a distance spectrum by subjecting the analyzed data further to spectrum analysis, thereby calculating the distance to the measurement object (6).

25 citations

Patent
Walt Devensky1
23 May 2008
TL;DR: In this article, a radio altimeter with a high level of integrity is presented, which includes a processing path configured to process a return signal received from a receive antenna using a first modulation technique and a monitoring path configured to process the return signal from the receive antennas using a second modulation technique.
Abstract: A radio altimeter having a high level of integrity is presented. The radio altimeter includes a processing path configured to process a return signal received from a receive antenna using a first modulation technique and a monitoring path configured to process the return signal received from the receive antenna using a second modulation technique.

22 citations

Journal ArticleDOI
TL;DR: It has been confirmed that short distances to multiple targets, such as the distances of two targets located at 0.5 m and 1 m, can be measured by the fundamental principle of this method applied to measurement of short distance for multiple targets using sound wave.
Abstract: Distance to target is fundamental and very important information in many engineering fields. In some applications sound is often used to measure distances to targets. For this purpose, the time delay of reflected wave is typically used. This method, however, can not measure short distance because the transmitted wave, which has not attenuated enough as of reception of reflected waves, suppresses the reflected waves for short distance. Meanwhile, in the research field of microwave radar, to measure distances to multiple targets even if they are short, a novel method by using standing wave has been recently proposed. In this paper, we apply the fundamental principle of this method to measurement of short distance for multiple targets using sound wave. Specifically, we focus our attention on audible band-limited signal with random phases. To verify the validity and effectiveness of our method, we perform computer simulations and experiments. As a result, it has been confirmed that short distances to multiple targets, such as the distances of two targets located at 0.5 m and 1 m, can be measured by our method.

19 citations