• 대한임베디드공학회논문지
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• 제6권5호
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• pp.319-325
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• 2011

Recently, collision avoidance systems are under development to reduce the traffic accidents and driver comfort for automotive radar. Pulse radar can detect their range and velocities of moving vehicles using range gate and FFT(Fast Fourier Transform) of the doppler frequency. We designed the real time DSP(Digital Signal Processing) based automotive UWB(Ultra Wideband) radar, and implemented DSP to detect the range and velocity within 100ms for real time system of the automotive UWB radar. We also measured the range and velocity of a moving vehicle using designed automotive UWB radar in a real road environment.

• 대한임베디드공학회논문지
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• 제6권5호
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• pp.281-286
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• 2011

FMCW Radar sensor is commonly used for an automobile collision avoidance system for rider's safe. Systems using FMCW radar, however, would be one of expensive solutions for just simple rear obstacle detection purpose due to its high cost. In this letter, a short range rear obstacle detector using novel 24GHz AM radar sensor is presented. It can be implemented at significantly lower cost than FMCW radar for practical commercialization. The proposed AM radar sensor module is fabricated in a single aluminum housing to reduce the overall size while using single power supply voltage of 12V with 1200mA current for automotive applications. The measured detection range is up to 210cm with 10cm of distance resolution, which is suitable for a parking assistance system for automobiles.

• 대한임베디드공학회논문지
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• 제13권1호
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• pp.1-8
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• 2018

This paper proposes a low complexity super resolution algorithm for frequency modulated continuous wave (FMCW) radar systems for foreign object debris (FOD) detection. FOD radar has a requirement to detect foreign object in small units in a large area. However, The fast Fourier transform (FFT) method, which is most widely used in FMCW radar, has a disadvantage in that it can not distinguish between adjacent targets. Super resolution algorithms have a significantly higher resolution compared with the detection algorithm based on FFT. However, in the case of the large number of samples, the computational complexity of the super resolution algorithms is drastically high and thus super resolution algorithms are difficult to apply to real time systems. In order to overcome this disadvantage of super resolution algorithm, first, the proposed algorithm coarsely obtains the frequency of the beat signal by employing FFT. Instead of using all the samples of the beat signal, the number of samples is adjusted according to the frequency of the beat signal. By doing so, the proposed algorithm significantly reduces the computational complexity of multiple signal classifier (MUSIC) algorithm. Simulation results show that the proposed method achieves accurate location even though it has considerably lower complexity than the conventional super resolution algorithms.

• 제어로봇시스템학회논문지
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• 제9권6호
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• pp.420-424
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• 2003

A new adaptive filter is proposed for an aided strapdown inertial navigation system(SDINS). The proposed filter can be used to effectively estimate the time-varying variance of the measurement noise. Then, the in-flight alignment for the radar aided SDINS is designed using the additive quatermion error model. Simulation results show that the proposed adaptive filter effectively improves the performance of the radar aided SDINS.

• 대한임베디드공학회논문지
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• 제12권2호
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• pp.71-77
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• 2017

This paper proposes a low complexity frequency modulated continuous wave (FMCW) surveillance radar algorithm. In the conventional surveillance radar systems, the two dimensional (2D) fast Fourier transform (FFT) method is usually employed in order to detect the distance and velocity of the targets. However, in a surveillance radar systems, it is more important to immediately detect the presence or absence of the targets, rather than accurately detecting the distance or speed information of the target. In the proposed algorithm, in order to immediately detect the presence or absence of targets, 1D FFT is performed on the first and M-th bit signals among a total of M beat signals and then a phase change between two FFT outputs is observed. The range of target is estimated only when the phase change occurs. By doing so, the proposed algorithm achieves a significantly lower complexity compared to the conventional surveillance scheme using 2D FFT. In addition, show in order to verify the performance of the proposed algorithm, the simulation and the experiment results are performed using 24GHz FMCW radar module.

• 제어로봇시스템학회논문지
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• 제22권8호
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• pp.633-642
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• 2016

It is important for advanced active safety systems and autonomous driving cars to get the accurate estimates of the nearby vehicles in order to increase their safety and performance. This paper proposes a sensor fusion method for radar and vision sensors to accurately estimate the state of the preceding vehicles. In particular, we performed a study on compensating for the lateral state error on automotive radar sensors by using a vision sensor. The proposed method is based on the Interactive Multiple Model(IMM) algorithm, which stochastically integrates the multiple Kalman Filters with the multiple models depending on lateral-compensation mode and radar-single sensor mode. In addition, a Probabilistic Data Association Filter(PDAF) is utilized as a data association method to improve the reliability of the estimates under a cluttered radar environment. A two-step correction method is used in the Kalman filter, which efficiently associates both the radar and vision measurements into single state estimates. Finally, the proposed method is validated through off-line simulations using measurements obtained from a field test in an actual road environment.

• 한국항행학회논문지
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• 제23권2호
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• pp.134-141
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• 2019

레이다 시스템은 송신 파형에 따라 크게 PD (pulse Doppler) 레이다와 FMCW (frequency modulated continuous wave) 레이다로 구분되며, 송수신 특성에 따라 PD 레이다는 장거리 표적 검출에 유리한 반면, FMCW 레이다는 단거리 표적 검출에 적합한 특성을 갖는다. 이에 본 논문에서는 중/장거리 뿐 아니라 단거리 무인기 탐지를 위해 PD 레이다 시스템과 FMCW 레이다 시스템을 모두 지원 가능한 멀티모드 레이다 신호처리 프로세서 (RSP; radar signal processor)를 제안한다. 제안된 레이다 신호처리 프로세서는 Verilog-HDL을 이용하여 RTL 설계 후, Altera Cyclone-IV FPGA를 이용하여 구현 및 검증 되었다. 구현 결과, 총 19,623개의 logic elements, 9,759개의register, 그리고 25,190,400의 memory bit로 구현 가능함을 확인하였으며, 기존의 PD 레이다와 FMCW 레이다 신호처리 프로세서를 개별 구현한 경우에 비해 logic elements와 register 요구량이 약 43%와 39% 감소됨을 확인하였다.

• 한국군사과학기술학회지
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• 제19권4호
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• pp.443-452
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• 2016

Current low-altitude radar system often fails to detect small unmanned aerial vehicles (UAV) because of their small radar cross section (RCS) compared with larger targets. As a potential alternative, a passive bistatic radar system has been considered. We study an optimal deployment problem for the passive bistatic radar system. We model this problem as a covering problem, and develop an integer programming model. The objective of the model is to maximize coverage of a passive bistatic radar system. Our model takes into account factors specific to a bistatic radar system, including bistatic RCS and transmitter-receiver pair coverage. Considering bistatic RCS instead of constant RCS is important because the slight difference of RCS value for small UAVs could significantly influence the detection probability. The paired radar coverage is defined by using the concept of gradual coverage and cooperative coverage to represent a realistic environment.

• International Journal of Fuzzy Logic and Intelligent Systems
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• 제12권4호
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• pp.263-269
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• 2012

The ability to characterize feature objects from radar readings is often limited by simply looking at their still frame reflectivity, differential reflectivity and differential phase data. In many cases, time-series study of these objects' reflectivity profile is required to properly characterize features objects of interest. This paper introduces a novel technique to automatically track multiple 3D radar structures in C,S-band in real-time using Doppler radar and profile their characteristic reflectivity distribution in time series. The extraction of reflectivity profile from different radar cluster structures is done in three stages: 1. static frame (zone-linkage) clustering, 2. dynamic frame (evolution-linkage) clustering and 3. characterization of clusters through time series profile of reflectivity distribution. The two clustering schemes proposed here are applied on composite multi-layers CAPPI (Constant Altitude Plan Position Indicator) radar data which covers altitude range of 0.25 to 10 km and an area spanning over hundreds of thousands $km^2$. Discrete numerical simulations show the validity of the proposed technique and that fast and accurate profiling of time series reflectivity distribution for deformable 3D radar structures is achievable.

• 한국전자파학회논문지
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• 제29권12호
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• pp.976-985
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• 2018

현대의 레이다는 위상 배열 안테나로 전자기파 빔을 생성하여 여러 가지 작업을 수행한다. 레이다가 수행하는 작업으로는 목표물의 탐지와 추적, 미사일 유도 등이 있다. 다기능 레이다가 개발되기 이전에는 레이다는 한 가지 작업만을 수행할 수 있기에, 각 작업을 수행하는 독립된 레이다가 필요했다. 하지만 다기능 레이다는 다양한 작업을 총괄하여 수행할 수 있는 기능을 탑재하고 있기 때문에, 하나의 레이다로 필요한 여러 작업을 수행할 수 있다. 레이다의 한정된 시간 자원을 효율적으로 이용하기 위해 예약된 작업을 적당한 순서로 나열하는 기법을 스케줄링이라고 한다. 본 연구에서는 두 가지의 스케줄링 기법들을 파악하여 효율적인 스케줄링 기법을 제시하여 보았다.