• Journal of Advanced Navigation Technology
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• v.21 no.4
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• pp.359-364
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• 2017

Since the existing analog village broadcasting system has some technical problems in applying and degradations in performance due to its old equipments, it had been required recently to be changed to a wireless digital system and to develop the standardization. However, it is important to analyze the interference between villages in deploying the efficient digital wireless village broadcasting system. In this paper, simulations for co-channel and adjacent channel interference have been carried out considering digital private mobile radio(dPMR) and digital mobile radio(DMR) systems as a representative mobile radio. These results for frequency reuse and channel separation drawn from the separation distance between villages in co-channel interference and the frequency offset in adjacent interference can be helpful to establish a standard and the testing service in the near future.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.1
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• pp.291-296
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• 2006

The restrictions concerning the use of the radio waves have become severe, the marine radar with low spurious is being developed. Therefore, it is necessary to develop aids to navigation as a radar beacon can respond to new type of marine radar. Because the system of radar in the future is an indetermination, new radar beacon should correspond to old and new radar system during a transition period. New radar beacon that is also able to respond to pulse radar, pulse compression radar and FM-CW radar were considered in these years in Japan. The sign of the response of Morse code in a new system is generated by the delay synthesis system. Computer simulation and actual examination using trial circuit were curried out. A big possibility was set up in the development of the new radar beacon that was able to correspond to old and new radar system. These results and the state of new radar beacon is mentioned in this paper.

• Journal of Positioning, Navigation, and Timing
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• v.13 no.2
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• pp.207-213
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• 2024

This paper examines the frame boundary detection performance for a satellite navigation augmentation signal orthogonally modulated with Hadamard code to determine the number of message preamble bits. Simulation results show that, even in weak signal environments, designing the message preamble with 32 bits is recommended for achieving stable frame boundary detection.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.3
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• pp.756-763
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• 2015

NAVWAR (NAVigation WARfare) such as an integral part of EW (Electronic Warfare) for making navigation systems malfunctioning expands rapidly in the future military warfare. First of all, Navigation systems of ground radio and satellite were investigated. And the definition of NAVWAR and vulnerability related to GNSS were analyzed. As a result, we propose the development direction for future navigation system such as constructing eLoran system, developing an integrated receiver, establishing alert steps of watch system, and so on.

• Journal of Satellite, Information and Communications
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• v.8 no.4
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• pp.58-63
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• 2013

Since radio interference can degrade the performance of systems or limit the system operation, an accurate assessment of radio interference with the existing systems should be conducted prior to the operation of a new system. In this paper, we present an evaluation methodology for the radio interference between radio-navigation satellite service (RNSS) systems and mobile communication service (MS) system. Radio interferences from RNSS systems into MS system using minimum coupling loss (MCL) method are simulated and vice-versa, and the frequency sharing condition between two systems are derived in a same geographical area.

• Journal of Advanced Navigation Technology
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• v.23 no.4
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• pp.322-327
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• 2019

In this paper, we propose first a scheme of grouping spectrum holes that are created in the multiple channels of primary users, and then by using the scheme we enhance quality of service (QoS) of wideband cognitive radio users in cellular cognitive radio networks. In our scheme, spectrum holes created in each primary channel are predicted by Wiener prediction process, and then the predicted spectrum holes happened in the same time are grouped into a group. The wideband cognitive radio users explore the group of spectrum holes to improve their QoS. Simulation results show that their handoff calls dropping rate and initial calls blocking rate are significantly reduced in our scheme, compared to those in the single primary channel.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.25 no.10
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• pp.1028-1039
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• 2014

After DTV transition, frequency allocation to efficiently utilize 700 MHz band, which is remained as Digital Dividend, is in progress domestically and internationally. This paper investigates global frequency allocation of 700 MHz band and utilization of the band, and analyzes domestic wireless technology methods and requested frequency bandwidth by use. In addition, the paper suggests what needs to be considered in case of building public integrated radio network that focuses on disaster and safety network; the integrated radio network also includes railway network and e-Navigation.

• Journal of Advanced Navigation Technology
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• v.14 no.3
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• pp.303-312
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• 2010

VHF Omnidirectional Radio range(VOR) is used as an aircraft navigational aid. The VOR is a short-range air navigation system providing aircraft with its bearing relative to the ground station. The accuracy of a VOR must be checked in accordance with the current ICAO, FAA and domestic regulations. The primary purpose of performing VOR station ground checks is to minimize the need for expensive flight checks by determining the amount and direction of any course bearing inaccuracies being transmitted. In this paper we present current and advanced way of monitoring of VOR system. We verify this way by field test of the monitoring and it is a high performance way to achieve an improvement in accuracy and an effect compared to present monitoring system.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.25 no.4
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• pp.24-30
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• 2017

Obstacle defines all fixed and mobile objects, or parts thereof, that are located on an area intended for the surface movement of aircraft or extend above a defined surface intended to protect aircraft in flight or stand outside those defined surfaces and that have been assessed as being a hazard to air navigation. Aircraft operations are based on electronic supporting systems using radio frequencies to assist pilots. These frequencies can receive outside interference that change their courses or power, such as distortion, attenuation or reinforcements by an obstacle. This is a preliminary case study that shows the relation of instrument flight procedures and the degree of interferences introduced by a planned obstacle, which is a main bridge post, within the service volume of the radio navigation aids. For the purpose of this study, the case airport's data and it's VOR/DME and ILS systems' limitations are analyzed, as well as the relation of interferences between the obstacle and navigation aides were reviewed with the internal regulations in Korea.

• 한국해양학회지
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• v.14 no.2
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• pp.78-85
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• 1979

Korea has not any fixed station for Radio Navigation systems yet. In some part of the Korean Sea, however, Japanese stations can be utilized for the Radio Navigation. 3 Decca chains were proposed to install the Decca Navigation network for Korea. Only for the coverage area, 1 Decca chain is sufficient for the sea around Korea instead of 3 chains. At present, Omega system is the most recommendable for the positioning in the farther area. In nearshore area, Raydist or Decca Trisponder is is useful for obtaining the position with high accuracy.