• Journal of electromagnetic engineering and science
• /
• v.12 no.1
• /
• pp.70-76
• /
• 2012

We compare the detection probabilities of the time-reversal(TR) detection system and the conventional radar system. The target is assumed to be hidden inside a random medium such as a forest. We propose a TR detection system based on the SAR(Synthetic Aperture Radar) algorithm. Unlike the conventional SAR images, the proposed TR-SAR system has an interesting property. Specifically, the target-related signal components due to the time-reversal refocusing characteristics, as well as some of clutter-related signal components are concentrated at the time-reversal reference point. The remaining clutter-related signal components are scattered around that reference point. In this paper, we model the random media as a collection of point scatterers to avoid unnecessary complexities. We calculate the detection probability of the TR radar system based on the proposed simple random media model.

• Proceedings of the IEEK Conference
• /
• 2008.06a
• /
• pp.973-974
• /
• 2008

As radar signal environments become denser and more complex, the capability of high-speed and accurate signal analysis is required for ES(Electronic warfare Support) system to identify individual radar signals at real-time. In this paper, we propose the new novel clustering algorithm of radar pulses to alleviate the load of signal analysis process and support reliable analysis. The proposed algorithm uses KDE(Kernel Density Estimation) and its CDF(Cumulative Distribution Function) to compose clusters considering the distribution characteristics of pulses. Simulation results show the good performance of the proposed clustering algorithm in clustering and classifying the emitters.

• Journal of the Korea Institute of Military Science and Technology
• /
• v.16 no.4
• /
• pp.514-522
• /
• 2013

In this paper, we present signal processing procedure and carry out performance analysis of FMCW(Frequency Modulation Continuous Wave) radar for Autonomous Unmanned Vehicle(AUV). In order to detect range profile and velocity of the unknown target, we must implement two step FFT(Fast Fourier Transform) procedure. And the DBF(Digital Beam Forming) algorithm has to be performed to obtain the angle information of the unknown target. To verify the performance of manufactured autonomous unmanned ground vehicle FMCW radar, we use the data of the real corner reflecter target.

• Journal of Korea Multimedia Society
• /
• v.19 no.8
• /
• pp.1297-1309
• /
• 2016

In this paper, an efficient connected component labeling (CCL) method was proposed. The proposed method is based on GPU parallelism. The CCL is very important in various applications where images are analysed. However, the label of each pixel is dependent on the connectivity of adjacent pixels so that it is not very easy to be parallelized. In this paper, a GPU-based parallel CCL techniques were proposed and applied to the analysis of radar signal. Since the radar signals contains complex and large data, the efficiency of the algorithm is crucial when realtime analysis is required. The experimental results show the proposed method is efficient enough to be successfully applied to this application.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.35 no.6A
• /
• pp.611-621
• /
• 2010

When an enemy platforms transmit electronic jamming or tracking interference signal to a friendly ship's radar, the radar have to avoid the jamming and to track targets continually without losing the targets with the electronic protection techniques. Electronic protection is an essential key for a platform to survive in electronic warfare, for this purpose, jamming simulator was developed to provide electronic warfare environments for the test and evaluate the effectiveness of radar's electronic protection techniques. Jamming simulator has ability to generate a variety of deception and noise jamming signals using the DRFM which minimize phase distortions of 1GHz broadband radar signal with the phase sampling method. This paper presents the design contents of the jamming simulator to process the analysis of broadband radar signal and generate jamming signal, also proposes the algorithms of the deception and noise jamming and verifies the effectiveness of the simulator by field trial.

• Journal of the Korea Institute of Military Science and Technology
• /
• v.25 no.4
• /
• pp.347-354
• /
• 2022

The synthetic aperture radar(SAR) is an equipment that can acquire images in all weathers day and night based on radar signals. The on-board processor of satellite SAR generates transmission signal by digital signal processing, converts it into an analog signal and transmits to antenna. Until the transmission signal generated by on-board processor is output, the signal passes the transmission cables and analog devices. At this time, these hardware distort the signal and makes SAR performance worse. To improve the performance, pre-distortion technique is used. But, general pre-distortion using taylor series is not sufficient to compensate for the distortion. This paper suggests transmit signal design method with improved pre-distortion. This paper uses envelop sampling method and interpolation filter for frequency domain compensation. The proposed method accurately compensates the hardware distortion and reduces resource usage of FPGA. To analyze proposed method's performance, IRF characteristics are compared when the proposed method applies to signal with errors.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.19 no.11
• /
• pp.1204-1212
• /
• 2008

The paper proposes a new signal model which is revised from the commonly used signal model. Recently, many research institutions had a research about CW bio-radar for detecting he heartbeat and respiration. However, when the bio-radar detects the heartbeat using the previous signal model, the bio-radar has a disadvantage of weakness about he residual phase and AWGN. Also, the model is inappropriate in ergonomics because this signal model supposes hat the heart and lung are located at a same place. In this paper, the modified signal model, which is appropriate n ergonomics, is proposed. This paper analyzes and compares with the performance for detecting the heartbeat and respiration using the previous model and revised model in AWGN and multi-path environment.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.15 no.9
• /
• pp.1840-1846
• /
• 2011

It is necessary to estimate the Doppler spectrum for each range cell for the extraction of useful information from the return echoes in radar systems used for the remote sensing purpose such as detection of moving targets and weather surveillance. The signal amplitude in the beat frequency band is the important parameter in the detection and tracking of targets. However, strong clutter echoes do exist in most radar operation environments and the system phase noise spreads both the clutter and signal echoes of the target. In this paper, the effects of this system phase noise are analyzed concerning the clutter and the signal beat spectrum. It is shown that the separation capability of adjacent beat signal depends on the degree of spread in the clutter and beat signal caused by the radar system phase noise

• Journal of Satellite, Information and Communications
• /
• v.12 no.2
• /
• pp.1-10
• /
• 2017

In this paper we propose three existing reflection removal algorithms and one proposed algorithm to estimate accurate targets in near field using IR-UWB (Impulse-Radio Ultra Wideband) radar. The received signal includes unnecessary reflected wave signals to the target signal. A reflective cancellation algorithm was used to remove unnecessary signals and estimate only the correct target signal. The location of the targets is estimated in real time with one transmitting antenna and one receiving antenna. In order to overcome the disadvantages of the existing three reflection removal algorithms, we propose a new reflection removal algorithm and estimate the most accurate target. Also we used DSP(Digital Signal Processor) to install the external mounting of vehicles. This paper will contribute to the study of the future reflections.

• International Journal of Highway Engineering
• /
• v.18 no.6
• /
• pp.61-67
• /
• 2016

OBJECTIVES : The objective of this study is to detect road cavities using multi-channel 3D ground penetrating radar (GPR) tests owned by the Seoul Metropolitan Government. METHODS : Ground-penetrating radar tests were conducted on 204 road-cavity test sections, and the GPR signal patterns were analyzed to classify signal shape, amplitude, and phase change. RESULTS : The shapes of the GPR signals of road-cavity sections were circular or ellipsoidal in the plane image of the 3D GPR results. However, in the longitudinal or transverse direction, the signals showed mostly unsymmetrical (or symmetrical in some cases) parabolic shapes. The amplitude of the GPR signals reflected from road cavities was stronger than that from other media. No particular pattern of the amplitude was found because of nonuniform medium and utilities nearby. In many cases where road cavities extended to the bottom of the asphalt concrete layer, the signal phase was reversed. However, no reversed signal was found in subbase, subgrade, or deeper locations. CONCLUSIONS : For detecting road cavities, the results of the GPR signal-pattern analysis can be applied. In general, GPR signals on road cavity-sections had unsymmetrical hyperbolic shape, relatively stronger amplitude, and reversed phase. Owing to the uncertainties of underground materials, utilities, and road cavities, GPR signal interpretation was difficult. To perform quantitative analysis for road cavity detection, additional GPR tests and signal pattern analysis need to be conducted.