• 한국ITS학회:학술대회논문집
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• v.2006 no.10
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• pp.308-311
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• 2006

• Journal of the Korea Institute of Military Science and Technology
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• v.25 no.1
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• pp.23-29
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• 2022

As the application field of radar is expanded and the bandwidth increases, the number of radar sensors operating at the same frequency is continuously increasing. In this paper, we propose a method of analyzing interference when two pulse doppler radars are operated at the same frequency with different waveform which are designed independently. In addition, we show that even for a previously designed LFM waveforms, the interference can be suppressed without affecting the performance by changing the sign of the frequency slope by increasing/decreasing, or by modulating the pulses by the different codes. The interference suppression by different slopes is more effective for similar waveform and the suppression by the codes increases as the number of pulses increases. We expect this result can be extended to the cases where multiple radars are operated at the same frequency.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.46 no.1
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• pp.1-9
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• 2009

In this paper, a 2.4 GHz doppler radar system consisting of a doppler radar sensor and a baseband module were designed to detect heart beat and respiration signal without direct skin contact. The doppler radar system emits RF signal of 2.4 GHz toward human chest, and then detects phase modulation of the reflected signal so as to investigate cardiopulmonary activities. The heartbeat and respiration signals acquired from I/Q channels of the doppler radar system are applied to the pre-processing circuit, the amplification circuit, and the offset circuit of the baseband module. The designed system was tested on mouse, rabbit and mankind, which have different range of heart rates and respiration signals, to evaluate detection accuracy of the system. ECG acquisition system and respiration transducer were used to generate the reference signal. In our experiments, a performance of detection were found to be high in the case that the subject stays still. In this paper, we confirmed that non-contact heart beat and respiration detection using the doppler radar has the possibility and limitation according to distance, cardiopulmonary activities, range of heart rates and respiration.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.27 no.11
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• pp.996-1003
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• 2016

Trilateration technique using time of arrival(TOA) is generally used for single target position estimation in radar system. However, trilateration technique has limitation in case of multiple targets, since it is difficult to distinguish the measurements corresponding to the respective targets. In this study, to eliminate ambiguity of relation between measurements and targets, micromotion of each target is measured by micro Doppler which is actively studied in radar industry nowadays and these information are used to distinguish measurements used at trilateration technique. Resultingly, the trilateration technique is applied successfully for each target. The targets are considered as multiple submissiles separated from the missile. Simulation results shows the performance of the proposed algorithm.

• Journal of Biomedical Engineering Research
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• v.36 no.2
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• pp.48-53
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• 2015

Sudden infant death syndrome(SIDS) continues to be general cause of infant death. Also, apnea is supposed to be one of the main risk factor of SIDS. Therefore, Infant's respiratory monitoring and real-time apnea detection is very important to prevent SIDS. In this study, we proposed a non-contact home monitoring system for infant's respiration using Doppler radar in order to prevent SIDS. The respiration data were acquired from a commercialized baby simulator(Simbaby$^{TM}$) using a Doppler radar. To evaluate a performance of the proposed system, the simulator was placed in a supine and prone position and the chest belt was used simultaneously as a reference signal. As a result, correlation coefficients between respiration rates of Doppler radar and the chest belt in each position were 0.95(p < 0.001) and 0.98(p < 0.001), respectively. The averages of difference were $-0.29{\pm}5.21(mean{\pm}1.96{\cdot}$ standard deviation) in supine and $-0.12{\pm}3.05$ in prone from Bland-Altman analysis. The results indicated an excellent performance in detecting apnea with a sensitivity of 100% and a positive predictive value of 100% in each posture respectively. These results demonstrated that a proposed Doppler radar system is suitable for non-contact respiratory monitoring in order to prevent SIDS of infant.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.7
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• pp.815-821
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• 2012

A CW Doppler radar can measure radial velocity of an object. It detects a Doppler frequency shift that is proportioned to radial velocity of a moving object. To detect a Doppler frequency shift, FFT(Fast Fourier Transform) is conducted. In this process, the time domain received signal is transformed to a frequency domain. A number of FFT affects not only the time resolution but also signal to noise ratio of received signal. So finally it is related with a radial velocity accuracy. Therefore in this paper, it is described the relation of time resolution and the radial velocity accuracy.

• Journal of the Korea Institute of Military Science and Technology
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• v.11 no.3
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• pp.40-49
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• 2008

In this paper, we have described a Simulated Radar Target Generation Equipment(SRTGE) for evaluating the performance of a developed radar system. In order to change a simulated target range(or time delay), the variable optical delay line structure is used in SRTGE, In addition, SRTGE is required to generate a target return signal which is composed of variable amplitude and Doppler velocity. The interference such as noise jamming and clutter is also produced from SRTGE for evaluating ECCM(Electronic-Counter-Counter Measure) capability of radar.

• Journal of electromagnetic engineering and science
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• v.10 no.4
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• pp.250-255
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• 2010

This paper presents a non-contact measurement method of vital signal by the use of multiple-input multiple-output (MIMO) bio-radar system, configured with two antennas that are separated by a certain distance. The direction of arrival (DOA) estimation algorithm for coherent sources was applied to detect vital signals coming from different spatial angles. The proposed MIMO bio-radar system was composed of two identical transceivers sharing single VCO with a PLL. In order to verify the performance of the system, the DOA estimation experiment was completed with respect to the human target at angles varying between $-50^{\circ}$ and $50^{\circ}$ where the bio-radar system was placed at distances (corresponding to 50 cm and 95 cm) in front of a human target. The proposed MIMO bio-radar system can successfully find the direction of a human target.

• Journal of the Korea Institute of Military Science and Technology
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• v.13 no.6
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• pp.1139-1146
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• 2010

Simulated target generators are used to evaluate the various radar performance. Using the radar parameters such as target range(time delay), doppler frequency, target RCS, simulated target generator can be developed. Especially moving targets are simulated by control time delay and update target signal intensive for target range. Base on this concepts, in this paper, simulated target generators are designed and developed for X-band Radar performance test. Developed equipment is evaluated its performance and then tested with X-band Radar. This paper presents these design, development, and test results of developed target generator.

• Journal of the Korea Institute of Military Science and Technology
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• v.20 no.4
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• pp.482-490
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• 2017

The radar signal processing procedure is divided into the pre-processing such as frequency down converting, down sampling, pulse compression, and etc, and the post-processing such as doppler filtering, extracting target information, detecting, tracking, and etc. The former is generally designed using FPGA because the procedure is relatively simple even though there are large amounts of ADC data to organize very quickly. On the other hand, in general, the latter is parallel processed by multiple DSPs because of complexity, flexibility and real-time processing. This paper presents the radar signal processor design using FPGA which includes not only the pre-processing but also the post-processing such as doppler filtering, bore-sight error, NCI(Non-Coherent Integration), CFAR(Constant False Alarm Rate) and etc.