• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.4
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• pp.707-714
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• 2016

Active driving safety systems for vehicle, such as the front collision avoidance, lane departure warning, and lane change assistance, have been popular to be adopted to the compact car. For improving performance and competitive cost, FMCW radar has been researched to adopt a phased array or a multi-beam antenna, and to integrate the front and the side radar. In this paper we propose several efficient methods to implement the signal processing module of FMCW radar system using low cost DSP. The pulse width modulation (PWM) based analog conversion, the approximation of time-eating functions, and the adoption of vector-based computation, etc, are proposed and implemented. The implemented signal processing board shows the real-time performance of 1.4ms pulse repetition interval (PRI) with 1024pt-FFT. In real road we verify the radar performance under real-time constraints of 10Hz update time.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.20 no.3
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• pp.121-127
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• 2020

The small tracking radar targets the target in a real-time, fast-moving, fast-moving target against aircraft with a large RCS that is maneuvering at low speed and a small RCS aircraft maneuvering at high speed (fighters, drones, helicopters, etc.) It is a pulsed radar that detects and tracks. Performing a performance test on a tracking radar in a real environment is expensive, and it is difficult to quantitatively measure performance in a real environment. Describes the composition of the laboratory environment's comprehensive performance test facility and the main requirements and implementation of each configuration.Anechoic chambers to simulate the room environment, simulation target generator to simulate the signal of the room target, target It is composed of a horn antenna driving device to simulate the movement of a vehicle and a Flight Motion Simulatior (FMS) to simulate the flight environment of a tracking radar, and each design and implementation has been described.

• Korean Journal of Construction Engineering and Management
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• v.12 no.1
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• pp.85-96
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• 2011

The access monitoring and control system of vehicles involved in construction logistics has been evolved from paper-based through bar code-based and to RFID-based management with pursuing automatic data collection and management. However, existing management methods have a limit that they still need manpower allocation for access control of vehicles. Therefore this research has proposed an framework that includes devices and an information system for effective and efficient data collection for access control of vehicles for construction logistics. And the proposed framework has been verified through a laboratory test using a prototype system developed in this research. It is expected that the installation methods of RFID antenna and tag for the framework could be applied to not only the access control of construction site but also various RFID applications at construction sites.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.37 no.6
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• pp.805-814
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• 2013

A hydraulic dipod platform is used for tracking and stabilizing an antenna system to designate a satellite on a moving vehicle. The 2-DOF controller is very well suited to this controller design object because it is more flexible than the 1-DOF controller when the design object is not only the consideration between stabilizing and tracking but also the trade-off between performance and robustness. The 2-DOF controller synthesis based on the $H_{\infty}$ framework is divided into two design procedures. In this hydraulic dipod platform example, the single-step method shows better performance whereas the two-step method shows better robustness. The difference between these two synthesis results is compared using the structural property of the interconnection system matrix.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.42 no.4
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• pp.703-715
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• 2017

In this paper, we analyze the channel characteristics of the long distance air-ground wideband common data link and we propose a mathematical method to analyze the effect of narrowband and wideband interference of air-ground channel on the received signal of wideband data link. In this paper, we analyze the reception performance according to the communication distance using the proposed performance analysis method, and found out that the communication distance is limited by the narrowband and wideband interference of ground reflection wave. As a result of the performance analysis of the method of controlling the receiving antenna upward, not only the narrow band but also the wideband interference is effectively reduced, so that the communication distance is increased even in the existing wideband data link not including the equalizer.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.1
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• pp.99-107
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• 2008

Recently route guiding system using GPS is spread widely. In the parking management system of complex mall, RFID is mainly used to control status of parking lots. However, in a case that a vehicle only with RFID tag enters into small market-populated district with service of parking lots, there is no parking route guiding system optimized with information of real tine status of parking lots and the system only with GPS can't provide a function of using real time status of parking lots. This paper proposes a location recognizing method of RFID tag object for parking control system to integrated several parking lots in the business district and database-linked route guiding system optimized for parking. The proposed location recognizing method makes the search of optimized parking route possible by abstracting decoding order of tag and antenna number and recognizing direction of tag linked with database. Ihe implemented system that is composed of RFID tag, reader, middleware, server, parking lot clients and mobile clients shows that the proposed method works well and it will be useful for integrated parking control system.

• Journal of the Korean GEO-environmental Society
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• v.23 no.8
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• pp.17-22
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• 2022

To reduce the bump of bridge/earthwork transition area caused by the settlement of the soft ground during public use, the road agencies have been continuously overlay or repavement at those areas. In this study, the vehicle-mounted ground penetrating radar with 1GHz air-coupled antenna was used to estimate the settlement amount of those areas for nine bridges built in the soft ground. Results shows that it is possible to effectively measure the thickness of pavement up to a depth of 1 m on an asphalt road with ground penetrating radar technology that can inspect under the road surface. Distinctively deformation of the road surface, the variation in the thickness of the pavement measured at bridge/earth transition areas is equivalent to a minimum of 50 mm and a maximum of 600 mm, and there is a risk of cavity in the ground. The difference in the increased pavement thickness is 50~250 mm for each bridge connection, which may cause the differential settlement. In this study, by using the result of the ground penetration radar, a plan for improving drivability and maintenance of the settlement is suggested and applied to the field.

• The Journal of the Convergence on Culture Technology
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• v.9 no.5
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• pp.517-522
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• 2023

Existing radars have been developed by applying RF sub-array algorithms, and recently, fully digital Multiple-Input Multiple-Output (MIMO) radar algorithms have been implemented for vehicle radars. In this paper, the radar algorithm applying the Phased MIMO method to the hardware of the RF sub-array method, which is an unsecured technology, was implemented and verified in real time. In order to secure RF sub-array Phased MIMO algorithm technology, a hardware structure for FPGA-based real-time signal processing was presented, and performance was first predicted through design and simulation. Through this, the digital signal of FPGA-based broadband MIMO FMCW radar The processing hardware was developed, and the Phased MIMO radar algorithm of the RF sub-Array method was finally implemented and verified in real time. Based on this, it is judged that it will be possible to secure and apply core technologies necessary for terahertz band radar in the future.

• Korean Journal of Remote Sensing
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• v.30 no.2
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• pp.293-302
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• 2014

Radar systems are used in remote sensing mainly as space-borne, airborne and ground-based Synthetic Aperture Radar (SAR), scatterometer and Doppler radar. Those systems are composed of expensive equipments and require expertise and professional skills for operation. Because of the limitation in getting experiences of the radar and SAR systems and its operations in ordinary universities and institutions, it is difficult to learn and exercise essential principles of radar hardware which are essential to understand and develop new application fields. To overcome those difficulties, in this paper, we present the construction and experiment of a low-cost educational radar system based on the blueprints of the MIT Cantenna system. The radar system was operated in three modes. Firstly, the velocity of moving cars was measured in Doppler radar mode. Secondly, the range of two moving targets were measured in radar mode with range resolution. Lastly, 2D images were constructed in GB-SAR mode to enhance the azimuth resolution. Additionally, we simulated the SAR raw data to compare Deramp-FFT and ${\omega}-k$ algorithms and to analyze the effect of antenna positional error for SAR focusing. We expect the system can be further developed into a light-weight SAR system onboard a unmanned aerial vehicle by improving the system with higher sampling frequency, I/Q acquisition, and more stable circuit design.

• International Journal of Computer Science & Network Security
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• v.23 no.10
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• pp.1-10
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• 2023

This paper proposes a method to extend Inter-Carrier Interference (ICI) canceling Orthogonal Frequency Division Multiplexing (OFDM) receivers for 5G mobile systems to spatial multiplexing 2×2 MIMO (Multiple Input Multiple Output) systems to support high-speed ground transportation services by linear motor cars traveling at 500 km/h. In Japan, linear-motor high-speed ground transportation service is scheduled to begin in 2027. To expand the coverage area of base stations, 5G mobile systems in high-speed moving trains will have multiple base station antennas transmitting the same downlink (DL) signal, forming an expanded cell size along the train rails. 5G terminals in a fast-moving train can cause the forward and backward antenna signals to be Doppler-shifted in opposite directions, so the receiver in the train may have trouble estimating the exact channel transfer function (CTF) for demodulation. A receiver in such high-speed train sees the transmission channel which is composed of multiple Doppler-shifted propagation paths. Then, a loss of sub-carrier orthogonality due to Doppler-spread channels causes ICI. The ICI Canceller is realized by the following three steps. First, using the Demodulation Reference Symbol (DMRS) pilot signals, it analyzes three parameters such as attenuation, relative delay, and Doppler-shift of each multi-path component. Secondly, based on the sets of three parameters, Channel Transfer Function (CTF) of sender sub-carrier number n to receiver sub-carrier number l is generated. In case of n≠l, the CTF corresponds to ICI factor. Thirdly, since ICI factor is obtained, by applying ICI reverse operation by Multi-Tap Equalizer, ICI canceling can be realized. ICI canceling performance has been simulated assuming severe channel condition such as 500 km/h, 8 path reverse Doppler Shift for QPSK, 16QAM, 64QAM and 256QAM modulations. In particular, 2×2MIMO QPSK and 16QAM modulation schemes, BER (Bit Error Rate) improvement was observed when the number of taps in the multi-tap equalizer was set to 31 or more taps, at a moving speed of 500 km/h and in an 8-pass reverse doppler shift environment.