• Journal of Advanced Navigation Technology
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• v.17 no.3
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• pp.279-284
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• 2013

Among the phases of flight operations pilots feel much pressure in landing segment. There is a number of factors affecting landing safety while pilots reduce aircraft speeds and make a touchdown and stop completely. If runway length is sufficient for landing, there maybe is no problem. But it is not the case all the time. So it is necessary to confirm whether landing performance is within limits or not. Required landing distance is actual landing distance demonstrated by flight test pilot plus allowances for average airline pilots. FAR(Federal Aviation Regulations) AFM certification is based upon manual landing for dry and wet runway. Other runway conditions are not the certification basis. JAR dictates even contaminated/slippery runway is included by prescribed allowances. Automatic landing is not certification basis, so actual landing distances are provided. In this paper I would like to analyze distance allowances included in each type of runway condition. In addition there is no regulation about allowances for specific runway condition, I would suggest adequate allowances for that case.

• Journal of Advanced Navigation Technology
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• v.28 no.1
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• pp.15-20
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• 2024

The utilization of small unmanned aerial vehicles (UAVs) has expanded into both military and civilian domains, increasing the necessity for research to ensure operational safety and the efficient utilization of airspace. In this study, the calculation of minimum separation distances for the safe operation of small UAVs at low altitudes was conducted. The determination of minimum separation distances requires a comprehensive analysis of the total system errors associated with small UAVs, necessitating sensitivity analysis to identify key factors contributing to flight technology errors. Flight data for small UAVs were acquired by integrating the control system of an actual small UAV with a flight simulation program. Based on this data, operational scenarios for small UAVs were established, and the minimum separation distances for each scenario were calculated. This research contributes to proposing methods for utilizing calculated minimum separation distances as crucial parameters for ensuring the safe operation of small unmanned aerial vehicles in real-world scenarios.

• Journal of Advanced Navigation Technology
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• v.21 no.6
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• pp.593-600
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• 2017

This paper analyzes the performances of direction finding, interference cancellation, and beamforming performance by array antenna pattern measurement distance between the center of array antenna and reference emitter. Array antenna is widely adopted for example as wireless communications, radar, and sonar. In order to use array antenna, array antenna pattern must be known and it can be measured in anechoic chamber. However, the size of anechoic chamber is generally limited. So measurement error of array antenna can be occurred and this could effect performance decrease of direction finding, interference cancellation, and beamforming. It is verified by computer simulation that the performances of direction finding, interference cancellation, and beamforming by array antenna pattern measurement distance.

• Journal of Advanced Navigation Technology
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• v.19 no.4
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• pp.278-287
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• 2015

The potential impact of aircraft emissions on the current and projected climate of our planet is one of the more important environmental issues facing the aviation industry. Increasing concern over the potential negative effects of greenhouse gas emissions has motivated the development of an aircraft emission estimation and prediction system as one of the ways to reduce aircraft emissions and mitigate the impact of aviation on climate. Hence, in this research, using Piano-X software which was developed by Lissys Co., fuel consumption and emissions for 3 types of aircraft were estimated for different design payloads with various flight distances and flight paths. Fuel burns for economy speed, long range cruise speed, maximum range speed were also investigated with various flight distances and altitudes.

• Journal of Advanced Navigation Technology
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• v.23 no.5
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• pp.437-443
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• 2019

In this paper, a new algorithm for the calculation of the range between an LTE base station (BS) and a user equipment (UE) using time-of-arrival (TOA) measurements of LTE signals is proposed. First, the cell identity (cell ID) of the received signal is acquired using the primary synchronization signal (PSS) and secondary synchronization signal (SSS) to identify the BS transmitted the signal. The proposed algorithm exploits the cell-specific reference signal (CRS), the reference sequence inserted in commercial LTE signals, to estimate the time delay using 2D cross-correlation. The obtained TOA estimations can be used to calculate the range employed from the known BS location. The performance of the proposed algorithm is evaluated with the experiment performed using real LTE signals transmitted from the commercial BS.

• Journal of Advanced Navigation Technology
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• v.24 no.6
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• pp.613-619
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• 2020

Hybrid media access control (MAC) is used in internet of things (IoT) network, because of communication feature concern with data capacity and communication interval between gateway and sensor nodes and the cost efficiency. Hybrid MAC consists of TDMA and CSMA generally. The distance between gateway and sensor node is openly changed in marine IoT network. Therefore, it is needed to control the period of timeslot of hybrid MAC used in marine IoT network. In this paper, the design rule of TDMA timeslot with the variable period depending on communication distance was proposed. It was confirmed from the analysis that 72 times communication between gateway and sensor nodes is possible in LoRa network by using the proposed TDMA variable timeslot scheme.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2003.05a
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• pp.5-10
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• 2003

This paper is mainly concerned with the assessment of safe navigation between ships moving each other in restricted waterways. The manoeuvring simulation was conducted parametrically to propose an appropriate sage speed and distance, which is required to avoid sea accident under the different conditions, such as ship-velocity ratios, ship-length ratios, separation and stagger between ships. The manoeuvring characteristics based on this investigation will be very useful for keeping the safety of navigation from the practical point of ships design and traffic control in confined water.

• Journal of Advanced Navigation Technology
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• v.11 no.4
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• pp.454-460
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• 2007

In this paper, we implemented a ray-tracing simulator with a ray-launching technique and generated the propagation path of each ray in an multiple-wall indoor environment. In this simulator, we adopted two dimension ray-tracing techniques considering the reflection and penetration were dominant propagation factor in the indoor channel. From the result, we verified that this ray-tracing simulator shows the similar pattern and delay distribution with the experiment results of the previous research.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.26 no.2
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• pp.167-172
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• 1990

A number of studies for the improvement of the accuracy of the Loran C fix were carried out previously. But most studies were preformed when a ship was at anchorage, or in port. To investigate the accuracy of the Loran C fix when a ship was underway and in port, a series of observation was made on the route between Pusan and Cheju from Oct. 1988 to Oct. 1989. The obtained results are summerized as follows: 1. There is little difference in the accuracy of the Loran C fix by daytime and night, and the higher the mountain nearby ship, the greater the error of ship's position. 2. When a ship is at anchorage and underway, and the accuracy of ship's position is almost not affected by course while underway. 3. In order to promote the accuracy of the fixed position, a navigator must correct the propagation velocity and the geodetic system simultaneously, but in this paper the authors find that a most accurate position can be obtained by converting the geodetic system only.

• Journal of Advanced Navigation Technology
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• v.6 no.2
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• pp.97-103
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• 2002

A recent technology trends in synthetic aperture radar(SAR) requires the ultra high resolution performance in detecting and precisely identifying the targets. In this paper, as a technique for enhancing the radar range resolution, the wide band chirp connection algorithm is presented by stitching the several chirp modules with unit bandwidth based on the linear frequency modulated chirp signal waveform. The principles of the digital chirp signal generation and its architecture for implementation is described with the wide band chirp signal generator, modulator, and demodulator. The performance analysis for the presented algorithm is given with the simulation results.