• Journal of the Korea Society of Computer and Information
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• v.15 no.5
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• pp.75-81
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• 2010

Adaptive array antenna system estimates target signal, as making a null pattern toward the interference signal. However, receiving a coherent interference signal at adaptive array antenna system, as target signal is regarded as interference signal, the performance of system rapidly decreases. The main beam does not direct an incidence direction of target signal due to sensitivity in directivity error. This paper proposes beamforming algorithm which combines high order limit condition and directivity error modify method. And it minimizes degree of freedom and decreases interference signal and directivity error using proposed algorithm. This paper compares and analyzes the performance of proposed algorithm and general algorithm using simulation. In this paper, the proposed algorithm correctly estimates an incident angle, but general algorithm occurs an error of about $0.8^{\circ}$.

• Journal of Sensor Science and Technology
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• v.1 no.2
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• pp.155-163
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• 1992

The phased array antenna has the ability to perform adaptive sampling by directing the radar beam without inertia in any direction. The adaptive sampling capability of the phased array antenna allows each sampling time interval to be varied for each target, depending on the acceleration of each target at any time. In this paper we design a three-dimensional adaptive tracking algorithm for the phased array radar system with a given set of measurement parameters. The tracking algorithm avoids taking unnecessarily frequent samples, while keeping the angular prediction error within a fraction of antenna beamwidth so that the probability of detection will not be degraded during a track update illuminations. In our algorithm, the target model and the sampling rate are selected depending on the target range and the target maneuver status which is determined by a maneuver detector. A detailed simulation is conducted to test the validity of our tracking algorithm for encounter geometries under various conditions of maneuver.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.3
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• pp.491-498
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• 2017

GPS (global positioning system) is a popular system that provides location information by measuring arrival time difference at the receiver between several GPS satellite signals. GPS is widely used in commercial area as well as military systems. Reliable GPS signal reception is more important in the military applications such as guided missiles. However, since the carrier frequencies of the GPS signals are well known and the received power is extremely low, the GPS systems are vulnerable to intentional jamming attacks. To remove jammers while maintaining GPS signals at the received signals, a popular technique is an adaptive beam steering method based on array antenna. Among adaptive beam steering techniques, this paper considers MVDR (minimum variance distortionless response) algorithm, and proposes a new adaptive technique that preserves the received signals at desired directions, but removes the unknown jamming signals adaptively. The performance of the proposed method is verified through computer simulation.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.7
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• pp.1539-1545
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• 2015

GPS (global positioning system) is a popular system that provides location information by measuring arrival time difference at the receiver between several GPS satellite signals. GPS is widely used in commercial area as well as military systems. Reliable GPS signal reception is more important in the military systems. However, since the carrier frequencies of the GPS signals are well known, the GPS receivers are vulnerable to intentional jamming attacks. To remove jammers but maintain GPS signals at the received signals, a popular technique is an adaptive beam steering method based on array antenna. Among adaptive beam steering techniques, this paper considers MVDR (minimum variance distortionless response) algorithm, and proposes a new adaptive technique that preserves the received signals at desired direction, but removes the jamming signals adaptively. The performance of the proposed method is verified through computer simulation.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.47 no.7
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• pp.80-84
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• 2010

A novel hybrid antenna array system for the code division multiple access (CDMA) using the diversity and beamforming technique has been proposed which is called as a dynamic selection method (DSM). Through the derived outage probability analysis, we have shown that the proposed DSM technique can give benefit over the conventional diversity-only or beamforming-only system.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.11 no.7
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• pp.1147-1155
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• 2000

The installation of wireless communication system for various services of ITS at 5.8 GHz generates mutual interference. The representative example, the sharing of frequency between DSRC system and ETC system is a cause of communication error or disturbance both sides or one side owing to mutual interference. As a solution, a Shield Plate, Antenna Directionality, Power Control is proposed, but these are not perfect solution, because a RSU doesn't have the information of position of interferer. This paper applies an adaptive array antenna which makes a gain for desired users, makes a null for interferer, to up-link, down-link of DSRC and ETC system. The analysis of BER performance shows the effect of reduced interference about 20 dB.

• Journal of Korea Society of Digital Industry and Information Management
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• v.5 no.3
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• pp.99-105
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• 2009

This paper suggests novel signal processing methods for optimal beamforming of smart antenna system in CDMA2000 mobile communication environments. This method utilize characteristics of the reverse pilot channel of CDMA2000 mobile communication systems, and applies them to improve the performance of an adaptive algorithm, which is used to a smart antenna system for beamforming. To perform the best beamforming, it is important to get an exact beamforming algorithm. This paper proposed an algorithm based on Laglange multiplier which has such an adaptive process, and also proposed the method to demodulate the received signal through array antenna using pilot channel in CDMA2000 environment. This paper analysed the enhanced performance of proposed algorithm in various signal environment through signal modeling of physical layer in CDMA2000 reverse link.

• The Journal of the Korea institute of electronic communication sciences
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• v.17 no.1
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• pp.23-30
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• 2022

The active phased array antenna system performs beam steering, multi-beam formation and adaptive beam forming by controlling the amplitude and phase of signals fed to each radiating element. In order to obtain the desired radiation characteristics using an active phased array antenna system, the accurate amplitude and phase of the signal must be fed to each radiating element; however, due to various causes, the signal errors occurs in each radiating element. In this paper, a signal error estimation method of each radiating element is proposed. The proposed method simplifies the process of signal error estimation, and can quickly and accurately calculate the signal error.

• Journal of the Korea Society of Computer and Information
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• v.13 no.4
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• pp.39-44
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• 2008

Wireless channel exists interference by multipath a component. Adaptation array antenna that remove this interference a component forms null point about interference signal and maximizes gains about target signal. If target signal and correlative coherent interference signal are received, there is problem that is removed from arrangement output to target signal. And, adaptation array antenna is shortcoming that is sensitive in directivity error. Therefore, in this paper, introduce each existing algorithm to solve directivity error about coherent interference, and proposed beam forming technique that minimize degree of freedom loss and damage because analyzes the problem and reduces coherent interference and directivity error.

• Journal of Satellite, Information and Communications
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• v.12 no.1
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• pp.43-48
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• 2017

Recently, demands on civilian UAV (Unmanned Aerial Vehicle) has been increasing and appropriate communication system is required for the UAV. In this paper, the performance of the UAV communication system using commercial wireless mobile network is discussed. The main service area of the wireless mobile network is ground level however the flying range of the UAV is normally in high altitude. Because of this mismatch of service area the performance of the UAV communication system is degraded in high altitude. To compensate performance degradation of the UAV communications system in high altitude, adaptive array antenna is introduced which is able to overcome altitude limitation of the UAV communication system.