• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.20 no.6
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• pp.580-588
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• 2009

A Missile Warning Radar is an essential sensor for active protection system to detect antitank missile in all weather environments. This paper presents the design, development, and test results of L-band pulsed Doppler radar system for main battle tank. This radar system consists of 3 LRUs, which include antenna unit, transmitter and receiver unit and radar signal & data processing unit. The developed core technologies include the patch antenna, SSPA transmitter, coherent I/Q detector, DSP based Doppler FFT filter, adaptive CFAR, SIW tracking capability, and threat decision. The design performance of the developed radar system is verified through various ground fixed and moving vehicle test.

• Aerospace Engineering and Technology
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• v.1 no.1
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• pp.135-140
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• 2002

The position and trajectory of in-flight rocket are important informations to determine the flight safety of rocket. In general tracking system, radar and transponder are used to acquire position information. Rocket position and trajectory can be determined by using RF communication between ground station and in-flight rocket and antenna position data. Onboard transponder system is composed of RF receiving part, RF transmitting one, decoder and single TX/ RX antenna. Therefore circulator is necessary for minimizing RF signal interference. In this paper, the radar transponder system was developed to track the trajectory and position of KSR-Ⅲ by using radar.

• Proceedings of the KSRS Conference
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• 2003.11a
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• pp.1009-1011
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• 2003

The procurement of mobile microwave scatterometer involve the consideration to ensure vehicle and equipment selection full-filled technical requirement and safety standard in Malaysia. Designing, and modification works involve engineering methodology in determining and selecting a suitable hydraulic telescopic boom that suit a selected vehicle available from the market. The vehicle is also a delivery system for microwave remote sensing equipment and other accessories to any locations in Malaysia. Total loading to be carried by the vehicle is about 4500 kg and its overall weight must be 16,000 kg as recommended by hydraulic telescopic boom manufacturers. The telescopic boom will elevate microwave scatterometer system and antenna to a maximum height of 27 m, and can also be rotated through 360$^{\circ}$. A mechanism is incorporated in the system to enable tracking or monitoring angular movement of the hydraulic telescopic boom when positioned towards required target.

• Journal of the Korea Institute of Military Science and Technology
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• v.25 no.2
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• pp.117-124
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• 2022

Single-ring circular array antennas can be applied to direction finding systems in order to use nose-section in other purposes, and the interferometry is a proper direction finding method to those systems. We usually make the interferometer baseline long enough to achieve good angular accuracy. However, an interferometer with baseline longer than a half-wavelength has the ambiguity problem. In this paper, we present a novel method for solving the ambiguity problem in interferometry systems. This technique is based on the amplitude comparison method and the space division table, and it can place a target within the angular region in which the ambiguity problem does not occur by roughly estimating direction-of-arrival. The Monte Carlo simulation results show that proposed method can effectively remove the ambiguity problem in the system.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.39 no.3
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• pp.140-149
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• 2002

This paper describes the characteristics of beam-tilting slot away waveguide antennas for mobile DBS reception. As a basic study of slotted waveguide array, design for 16 slot elements located on a broad-wall waveguide is considered. Design parameters such as slot length, space between each slot and cross slot angle of antennas with the beam-tilting characteristics are calculated by method of moments. Based on these results, the radiation waveguide antennas with 16-element $\times$16-array are designed and fabricated. The measured main beam direction angles of the fabricated antennas are 48$^{\circ}$to 50$^{\circ}$depending on the measured frequencies and it shows good agreement with prediction. The measured 3 dB beam width of elevation pattern is about 13$^{\circ}$, and the axial ratio and the gain measured at DBS band are observed 2.8 dB below and 24 dBi above, respectively. In order to evaluate a performance of the fabricated waveguide planar antenna, it is combined with the satellite tracking control system and the field performance test of antenna mounted on a mobile vehicle is carried out at highway. During the measurement, it was possible to watch television without a break signal in a driving vehicle and an excellent performance of the proposed antennas was demonstrated.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.37 no.7
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• pp.851-856
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• 2013

Recently, as the tactical environment has changedto one of network-centric warfare, where all components are connected through a network, much emphasis has been placed on the use of an artificial satellite for achieving high communication speeds. To provide a high-quality artificial satellite link, stabilization is very important in a platform. Previous stabilization control techniques used PI control, which is commonly used for vessels. However, for ground terminals that require a higher communication speed, the antenna should move faster to track an artificial satellite within a short period of time. Moreover, the terminals must be equipped with proper sensors and algorithms so that they can detect and compensate for external disturbances while tracking the artificial satellite. In this study, through the analysis of the dynamic model of an antenna system, a stabilization algorithm for ground terminals was proposed;this algorithm shows high isolation performance in the low-frequency range and includes $PI^2$ control.

• Journal of the Korean Society for Precision Engineering
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• v.25 no.11
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• pp.90-94
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• 2008

Recently, a great deal of research is focused on the printed electronics. One of their mainly concerned products is printed RFID tag. RFID technology has attracted researchers and enterprises as a promising method for automatic identification, and they are expected to replace conventional bar codes in inventory tracking and management. The key to successful RFID technology lies in developing low-cost RFID tags and the first step in applying printing technology to RFID systems is to replace antennas that are conventionally produced by etching copper or aluminum. However, due to the printing quality variations, errors, and lower conductivity, the performance of the printed RFID antennas is lower than that of antennas manufactured by conventional etching methods. In this paper, the effect of variations in the printing conditions on the antenna performance is investigated. Three levels for each condition parameter is assumed and effect on the resonant frequency are examined experimentally based on orthogonal array. The most serious factor that affects the resonant frequency of the antenna is the non-uniformity of the edge and the resonant frequency is found to be lower as the non-uniformity increases.

• Journal of the Korea Institute of Military Science and Technology
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• v.15 no.6
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• pp.812-819
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• 2012

Interference and jamming are becoming increasing concern to a radar system nowdays. AESA(Active Electronically Steered Array) antennas and adaptive beamforming(ABF), in which antenna beam patterns can be modified to reject the interference, offer a potential solution to overcome the problems encountered. In this paper, we've developed a planar active phased array radar system, in which ABF, target detection and tracking algorithm operate in real-time. For the high output power and the low noise figure of the antenna, we've designed the S-band TRMs based on GaN HEMT. For real-time processing, we've used wavelenth division multiplexing technique on fiber optic communication which enables rapid data communication between the antenna and the signal processor. Also, we've implemented the HW and SW architecture of Real-time Signal Processor(RSP) for adaptive beamforming that uses SMI(Sample Matrix Inversion) technique based on MVDR(Minimum Variance Distortionless Response). The performance of this radar system has been verified by near-field and far-field tests.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.10C
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• pp.984-994
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• 2003

This paper proposes a novel blind adaptive algorithm for computing the weight vector of an antenna array system. The new technique utilizes a Generalized On-Off algorithm to obtain the weight vector maximizing the SINR(Signal to Interference plus Noise Ratio) of the received signal. It is observed that the proposed algorithm generates a suboptimal weight vector with a linear computational load(O(6N+8)). From the various simulations, it is confirmed that, when the signal environment becomes adverse, e.g., low Processing Gain, and/or wide angular spread. the proposed algorithm outperforms the conventional one in terms of the communication capacity by about 3 times. Applying the proposed algorithm to satellite tracking systems as well as IS2000 1X mobile communication system, we have found that both communication capacity and communication quality are significantly improved.

• Journal of Satellite, Information and Communications
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• v.3 no.1
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• pp.41-47
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• 2008

Line-of-sight communications cannot easily support korean armed forces because of mountainous terrain. ADD(Agency for Defense Development) introduced ANASIS(Army Navy Air-force Satellite Information System) to meet the Korean warfighter's operational needs. Currently, army's military satcom terminal is designed for either fixed site or on-the-pause operation. The US army is under development of multi-band integrated on-the-move satellite terminals to let the army's communication capability to keep pace with globally deployable Joint Task Force for network-centric application. In this paper we analyzed X-band and Ka-band link and subsystem requirement. Our focus here is to describe key technical issues. Especially, On the basis of 3dB beam width of 0.9m antenna, Tracking accuracy and disturbances compensation signal processing on-the-move of Antenna Tracking system is analyzed. Also, protocol is analyzed that minimize blockage on the move due to an obstacle. when the received signal blocked, it stop to transmit burst signal and retransmit when blockage removed through received synchronization signal monitoring. Analyzed specification will be used to make prototype terminal to analyze risk for mass production