• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.28 no.10
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• pp.802-809
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• 2017

This paper presents a novel apnea detection and respiration rate estimation method using impulse-radio ultra-wideband (IR-UWB) radar. The proposed method utilizes amplitude, time of arrival, and power in the selected band. The experimental results show that respiration rate can be estimated accurately using proposed method. And, it is shown that the selectivity between apnea and respiration can be improved more than 50 dB using the proposed method.

• Proceedings of the KSRS Conference
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• 2007.10a
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• pp.254-257
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• 2007

This paper presents an examination of the spatial integration method for extracting the RCS of a trihedral corner reflector from SAR images for SAR external calibration. An exact external radiometric calibration technique is required for extracting an exact calibration constant. Therefore, we examine the accuracy of the spatial integration method, which is commonly used for the SAR external radiometric calibration. At first, an SAR image for a trihedral corner reflector is simulated with a high-resolution SAR impulse response with a known theoretical RCS of the reflector, and a background clutter image for the high resolution SAR system is also generated. Then, a SAR image in a high resolution is generated for a trihedral comer reflector located on a background clutter by superposition of the two SAR images. The radar cross section of a trihedral corner reflector in the SAR image is retrieved by integrating the radar signals of the pixels adjacent to the reflector for various size of the integration area. By comparison of the measured RCS by the integration method and the theoretical RCS of the reflector, the effect of the size of the integration area on the extraction of the calibration constant is examined.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.10 no.6
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• pp.889-899
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• 1999

A technique to obtain an exact frequency characteristics of desired targets in radar measurements is presented. The pulsing network composed of two RF switches was installed between the Network Analyzer and the antenna, and the backscattering from a metal sphere was measured at X-band. It is shown that the pulsing effectively eliminated undesired returns from antenna and other circuitry of the systems. The antenna return was suppressed by more than 60 dB, and the signal-to-noise ratio was improved drastically. The pulsed frequency data were processed to extract the responses of the desired target. The result agrees well with the theoretical backscattering characteristics of the sphere. The methods presented here are applicable to RCS measurements in compact ranges, and also to the backscattering measurements of distributed targets outdoors.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.11 no.4
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• pp.565-574
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• 2000

A new ground penetrating radar imaging method for the estimation of buried artificial structures location and their approximate shapes in dispersive lossy ground is investigated. Fundamental idea is based on estimating delayed time and amplitude retrieval coefficients from scattered signals by buried scatterers. Using absolute value integration of each scanning site not only improve the accuracy of measured scattered signal, but also offers convenient ways to extract the image of buried structures. Multi-term Debye model was employed to describe a dispersive and lossy ground medium. We used the finite difference time domain method to discretize the wave equation in continuous form into the machine suitable form. This imaging method uses a new wave path tracing technique in time domain, which is helpful to identify the exact position of buried structures against the ground surface fluctuations.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.10a
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• pp.754-756
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• 2013

The modern Electronic Warfare Receivers are required to the current radar technologies like the Low Probability of Intercept(LPI) radars to avoid detection. LPI radars have features of intra-pulse modulation differ from existing radar signals. This features require counterworks such as signal confirmation and identification. Hence this paper presents a study on intra-pulse modulation recognition. The proposed method automatically recognizes intra-pulse modulation types such as LFM and NLFM using classifiers extracted from the features of each intra-pulse modulation. Several simulations are also conducted and the simulation results indicate the performance of the given method.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.20 no.4
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• pp.35-41
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• 2020

The small tracking radar is a very important component of the wire harness design because the components are organically connected. In addition, the cable connected to the signal processing unit and the servo unit having a large number of digital signals should be prepared to prevent the CPU of the signal processing unit from malfunctioning due to electromagnetic noise. Cables for signal transmission in the ◯◯ GHz band must reflect the design of temperature, vibration, and shock. To design a wire harness in a small space, the size of the connector must be minimized. The issues to be considered are described and the design plan is presented.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2017.05a
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• pp.733-734
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• 2017

Ultrasonic, infrared, and CCD cameras are typically used to obtain location information, but the error range is large depending on the surrounding environment. However, IR-UWB can be used for distance and location measurement both indoors and outdoors, Technology. It is possible to determine the existence and distance of an object by emitting a short signal width in units of 1 ns and using a reflected signal and a time delay. It is also possible to measure the exact position within the cm error irrespective of the environmental conditions. Since it processes a large number of reflection signals, we try to measure three-dimensional spatial coordinates by improving the noise by using the mean value of the signal, the band pass filter and the FFT.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.5C
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• pp.555-560
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• 2009

A vehicle radar has been studied to avoid the collision of vehicles. A vehicle radar using direct sequence-ultra wideband (DS-UWB) measures the distance between a vehicle and an objective with a sufficient time margin. Therefore, the receiver should estimate the distance by processing the short UWB pulse rapidly. There have been several investigations for distance measuring based on DS-UWB signals. In this paper, we propose a novel method for rapid measuring processing time. Simulation results show that the proposed method has a shorter processing time than the conventional method.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.9
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• pp.1999-2005
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• 2015

A wind velocity is measured in a weather radar as well as the strength of return echoes from rain clouds. These wind velocities are obtained through estimation of Doppler frequencies in return signals. This kind of Doppler frequency estimation method is called as a correlation method. It is widely used in most weather radars because of less computation time. However, it may cause serious errors if a spectrum is not symmetric. Therefore, in this paper, it is shown that the improved method using 3^rd order phase estimation model yields the more accurate estimation of the average Doppler frequency using various simulated weather data.

• The Journal of the Korea institute of electronic communication sciences
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• v.13 no.6
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• pp.1191-1198
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• 2018

The wind profiler radar provides a standing profile of the wind vector and the atmospheric physical signal for the fixed point. Since the wind vector is calculated by the manufacturer's data processing program, the quality control of the date is limited. Therefore, understanding and exploiting the raw spectrum data need to improve the quality of the wind vector. The raw data of the wind vector is the power spectral density stored in binary form. In this study, an algorithm was completed to transform the raw data into the real spectral density, and the use of raw data was evaluated by retrieving zero-order and first-order moments of the spectral based on the spectrum quality control.