• Proceedings of the IEEK Conference
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• 대한전자공학회 1999년도 추계종합학술대회 논문집
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• pp.27-30
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• 1999

A spatio-temporal vector channel model is introduced for the position location (PL) estimation problem for CDMA cellular system environment. Two common ways for the PL make use of the AOA (Angle Of Arrival) and TDOA (Time Difference Of Arrival) from a subscriber to the multiple sensors (base stations). In this paper, we applied the derived vector channel to simulate the multipath channel for the angle of the signal arrival in CDMA systems. Cross-correlation method is a good candidate among other direction finding algorithms available in literature, especially in wideband modulation as in the CDMA system. The PL estimation errors are evaluated for different channels, which are obtained as a parameter of scattering radius of the suggested model. We noted that the number of sensors (base-stations) are related to the PL errors in favor of the available data.

• Journal of the Korea Institute of Military Science and Technology
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• 제21권4호
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• pp.447-455
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• 2018

If a hidden enemy is shooting, there is a threat against soldiers in recent conflicts. This paper aims to improve the localization of a muzzle using microphone array. Gunshot noise can provide information about the location of muzzle with two signals, the muzzle blast from the gun barrel and the projectile sound from the bullet. Two signals arrive to the microphone array with different arrival time and angle. If the arrival angles of the two signals are estimated, distance between sniper location and the microphone array can be calculated by using geometric principles. This method was established in 2003 by Pare. But this method has a limitation that it cannot calculate the distance when the arrival angles of the two signals are same. Also it has an error when the angle difference of arrival is small. In order to overcome this limitation, a new method is proposed that uses the change of characteristic of the projectile sound with respect to vertical distance from the trajectory. The proposed method estimates the distance correctly when the arrival angle of two signals are same, and when the angle difference between two signals is increased, the estimation error increases with respect to the angle. Therefore these two methods can be selected according to the angle difference between two signals to estimate the distance of the muzzle. Below the threshold of the angle difference, the proposed method can be used to estimate distance with smaller error than the existing method. This was demonstrated by shooting tests using actual sniper rifles.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• 제49권3호
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• pp.175-183
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• 2021

This paper studies measurement of sonic boom created by supersonic flight and its arrival angle estimation techniques. Since sonic boom propagates as an impulsive noise and includes infrasound frequency, we propose measurement instrumentation acquiring sonic boom signature without distortion. And we suggest the methodology for an arrival angle estimation with its performance analysis in accordance with sensor array configurations. The performance of our estimator is verified by comparing theoretical performance bound with statistics of its Monte-Carlo simulation results. Furthermore, we presents the analysis of the sonic boom measurement from real flight tests. This work provides an intuitive concept for sensor array configurations and measurement instrumentation.

• Journal of Positioning, Navigation, and Timing
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• 제10권2호
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• pp.131-137
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• 2021

The Angle-of-Arrival (AOA) estimation in real time is one of core technologies for the real-time tracking system, such as a radar or a satellite. Although AOA estimation algorithms for various antenna types have been studied, most of them are for the single-shaped array antenna suitable to the specific frequency. In this paper, we propose the cascade AOA estimation algorithm for the combined array antenna with Uniform Rectangular Frame Array (URFA) and Uniform Circular Array (UCA), with the excellent performance for various frequencies. The proposed technique is consisted of Capon for roughly finding AOA groups with multiple signal AOAs and Beamspace Multiple Signal Classification (MUSIC) for estimating the detailed signal AOA in the AOA group, for the combined array antenna. In addition, we provide computer simulation results for verifying the estimation performance of the proposed algorithm.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• 제9권2호
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• pp.137-144
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• 2009

This paper deals with the performance comparison of jammer signal's angle spreading in the beamforming after the estimation of direction of arrival using 3D array antenna basis of the GPS signal. After the estimation of direction of arrival using array antenna, the beamforming is need for the direction of arrival by spatial filtering and the other direction are nulling for reducing intererence signal, it is possible to improving the received signal strength and quality. But we obtains the degraded performance by the angle spreading due to the multi-jammer signal in this process. In this paper, the MUSIC and LCMV algorithms are applied for the estimating the direction of arrival and for beamforming using the 5 types of 3D array antenna. we performs the comparison of performance by calculating the bit error rate applying the BPSK modem and the varying the azimuth and elevation angle of incoming jammer signal. As a result of simulation, the Curved (B) type 3D array antenna has a more better performance compared to the other type antenna.

• The Journal of Korean Institute of Communications and Information Sciences
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• 제33권11C호
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• pp.949-954
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• 2008

An ultrawide band (UWB) signal model is proposed to estimate the angle-of-arrivals of the signals arrived in clusters at an UWB receiver for a short-range, high-speed, indoor wireless communication system in an elliptical scattering environment. And a new estimation technique is proposed by modifying the conventional MUSIC algorithm. By using this estimation technique, the estimates of the two unknown parameter sets, angle-of-arrivals and distribution parameters, are obtained with the proposed UWB signal model. The proposed UWB signal model and estimation technique are verified through computer simulations in an ultrawide band communication environment.

• Journal of Positioning, Navigation, and Timing
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• 제9권3호
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• pp.215-220
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• 2020

This paper deal with estimating the direction of arrival (DOA) of GNSS signal using two antennae for spoofing detection. A technique for estimating the azimuth angle of a received signal by applying the interferometer method to the GPS carrier signal is proposed. The experiment assumes two antennas placed on the earth's surface and estimates the azimuth angle when only GPS signal are received without spoofing signal. The proposed method confirmed the availability through GPS satellite placement simulation and experiments using a dual antenna GPS receiver. In this case of using dual antenna, an azimuth angle ambiguity of the received signal occurs with respect to the baseline between two antennas. For this reason, the accurate azimuth angle estimation is limits, but it can be used for deception by cross-validating the ambiguity.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• 제23권3호
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• pp.410-413
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• 2012

This study describes the performance comparison to solve angle ambiguity needed to angle of arrival estimation in 2D radiometer. There are three algorithms to solve its ambiguity such as phase-comparison monopulse method, digital beam-forming method and least square error of the phase difference in 2D radar interferometer. To estimate two direction angles, phase-comparison monopulse method is sequentially applied to azimuth and elevation direction. To analyze the performance of these methods, probability of solving angle ambiguity and execution time have been chosen as performance indexes. Through the Monte Carlo simulation, we have verified that phase-comparison monopulse method is most effective in real-time signal processing application.

• Journal of Advanced Navigation Technology
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• 제19권6호
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• pp.558-563
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• 2015

There have recently been various services that use indoor location estimation technologies. Representative methods of location estimation include fingerprinting and triangulation, but they lack accuracy. Various kinds of research which apply existing location estimation methods like AOA, TOA, and TDOA are being done to solve this problem. In this paper, we study the location estimation algorithm based on AOA using a RSSI difference in indoor environments. We assume that there is a single AP with four antennas, and estimate the angle of arrival based on the RSSI value to apply the AOA algorithm. To compensate for RSSI, we use a recursive averaging filter, and use the corrected RSSI and the Pythagorean theorem to estimate the angle of arrival. The results of the experiment, show an error of 18% because of the radiation pattern of the four non-directional antennas arranged at narrow intervals.

• The Journal of Korean Institute of Communications and Information Sciences
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• 제35권5C호
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• pp.472-478
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• 2010

In the environment of wireless communication system of IEEE 802.15.3a UWB standard, the angle of arrival(AOA) estimation technique for the indoor wireless positioning algorithms, based on the AOA parameter estimation which fits well for the wireless communication channel and shows high estimation accuracy, is proposed. After the UWB signal model, based on the IEEE 802.1.3a standard, is constructed, the average weighted MUSIC technique is proposed, which shows better estimation accuracy than those of conventional estimation technique. Through the simulation studies, the environment of the indoor wireless positioning system including the IEEE 802.15.3a channel is configured and we demonstrate better estimation results by the proposed AOA estimation technique than those from the conventional method.