• Title/Summary/Keyword: Military Communication

Search Result 743, Processing Time 0.024 seconds

Performance Comparison of Image Transmission in Underwater Acoustic Environment (수중 음향 환경에서의 영상 전송 성능 비교분석)

  • Lee, Seung-Woo
    • Journal of the Korea Institute of Military Science and Technology
    • /
    • v.11 no.3
    • /
    • pp.19-29
    • /
    • 2008
  • Underwater acoustic(UWA) communication is one of the most difficult field in terms of severe channel environments such as multipath propagation, high temporal and spatial variability of channel conditions. Therefore, it is important to model and analyze the characteristics of underwater acoustic channel such as multipath propagation, transmission loss, reverberation, and ambient noise. In this paper, UWA communication channel is modeled with a ray tracing method and applied to image transmission. Quadrature phase shift keying(QPSK) and multichannel decision feedback equalizer(DFE) are utilized as phase-coherent modulation method and equalization technique, respectively. The objective is to improve the performance of the image transmission using vertical sensor array instead of single sensor in the viewpoint of bit error rate(BER), constellation diagram, and received image quality.

A Study of Anti-Jamming Performance using A-NED(Adaptive NED) Algorithm of SFH(Slow Frequency Hopping) Satellite Communication Systems in PBNJ (부분 대역 재밍 환경에서 SFH(Slow Frequency Hopping) 위성 통신 방식을 사용하는 A-NED(Adaptive NED) 알고리즘 항재밍 성능 분석)

  • Kim, Sung-Ho;Shin, Kwan-Ho;Kim, Hee-Jung;Kim, Young-Jae
    • Journal of the Korea Institute of Military Science and Technology
    • /
    • v.13 no.1
    • /
    • pp.30-35
    • /
    • 2010
  • As of today, Frequency Hopping techniques are widely used for over-channel interference and anti-jamming communication systems. In this paper, analysis the performance of robustness on the focus of some general jamming channel. In FH/SS systems, usually SFH(Slow Frequency Hopping) and FFH(Fast Frequency Hopping) are took up on many special communication systems, the SFH, FFH are also combined with a channel diversity algorithm likes NED(Normalized Envelop Detection), EGC(Equal Gain Combines) and Clipped Combines to overcome jammer's attack. This paper propose Adaptive-NED and shows A-NED will be worked well than the others in the some general jamming environments.

A Performance Study of Tactical Data Link Transceiver in TDMA Networks (TDMA 네트워크 전술데이터링크 송수신기 구현 및 성능고찰)

  • Nam, Jeong-Ho;Seo, Nan-Sol;Jang, Dhong-Woon
    • Journal of the Korea Institute of Military Science and Technology
    • /
    • v.13 no.3
    • /
    • pp.388-396
    • /
    • 2010
  • Generally, flight information is transmitted by voice signal over legacy UHF radio in ground to air communication system. In this paper, we have implemented the transceiver of TDL(tactical data link) which transmits tactical information, such as flight information, using digital signal. For transmitting digital information over radio path, we have designed data modem that is processing CPFSK modulation, and TDMA(Time Division Multiple Access) network for Synchronization among multi user(platform). By simulating aeronautical propagation modeling with the environment of Korea terrain, it is predicted the maximum performance of communication range of the transceiver. As result of the transceiver's aviational boarding test, it is proved that the transceiver of TDL over legacy UHF radio transmits and receives the tactical information in TDMA network within communication range of 160km.

A Study on a New Carrier Recovery Algorithm for Coherent Burst-mode Communication Systems (동기식 버스트 통신시스템 적용을 위한 새로운 반송파 동기 기법에 관한 연구)

  • Park, Sung-Bok
    • Journal of the Korea Institute of Military Science and Technology
    • /
    • v.14 no.6
    • /
    • pp.1043-1048
    • /
    • 2011
  • In this paper, a newsynchronization technique applied to burst-mode communication is proposed. A synchronization technique is to estimate carrier frequency and phase offsets in a noisy channel environment. A fundamental problem for estimating the parameters(carrier phase and frequency offsets) in burst-mode transmission is that the ways of pursuing estimation accuracy and transmission efficiency are always trade-off. To solve this problem, a new carrier recovery technique is proposed to improve the transmission efficiency with reliable performance especially at low S/N. In the proposed technique, the synchronization parameters are first estimated based on a data-aided feed-forward estimation scheme. Then, a phase tracker using decision-directed DPLL estimates the phase offset for the data portion of the burst data. From simulation results, it shows fast synchronization with shorter preamble maintaining reasonable BER performance at low S/N.

A Study on Design and Implementation of a Test System for Underwater Communication Equipment (수중 통신 장비를 위한 검사기 설계와 구현에 관한 연구)

  • Yun, Hyeontae;Seok, Jongwon
    • Journal of the Korea Institute of Military Science and Technology
    • /
    • v.22 no.1
    • /
    • pp.42-48
    • /
    • 2019
  • Since the underwater telephone was sold in a short time, there are few repair equipments. And equipment is difficult to locate fault. Equipment with transducers must be inspected underwater, and a relative naval vessels is required to perform an operational check. So we developed a tester device to test the transmission card through the spectrum and transmission power, and to develop a device that can conduct operational tests on land. Therefore, the development of the tester reduces the incidence of naval vessels and contributes to the development of domestic underwater communication test equipment.

The Efficient Resource Allocation Scheme for the Satellite System based on MF-TDMA (위성 MF-TDMA 시스템을 위한 효율적인 자원할당 기법)

  • Choi, Byeong-Gon;Yeo, Bong-Gu;Kim, Seoung-Woo;Jeong, Won-Ho;Kim, Kyung-Seok
    • Journal of Satellite, Information and Communications
    • /
    • v.10 no.4
    • /
    • pp.32-38
    • /
    • 2015
  • Next generation military satellite communication systems have been developed for expanding capacity and survivability. As for expanding capacity, the communication systems require efficient techonology to use limited resource. So, next generation communication systems are expected to use MF-TDMA technology. MF-TDMA is the technology which has the advantages of FDMA and TDMA. By using MF-TDMA, communication systems can use limited resource efficiently, and the performance of resource allocation depends on the allocation scheme. In this paper, we propose efficient allocation scheme for next generation military satellite communication systems. Also, we compare and analze performances such as Total Resource Efficient, Reject Ratio, Computational Time, PSD distribution with existing allocation schemes.

The Design and Implementation of the Data Link System based on the Off-the-shelf Ultra Mobile Personal Computer for Network Centric Warfare(NCW) (네트워크중심전(NCW)을 위한 UMPC 기반 데이터 링크 시스템 설계 및 구축)

  • Sim, Dong-Sub;Kim, Ki-Hyung
    • Journal of the Korea Institute of Military Science and Technology
    • /
    • v.12 no.2
    • /
    • pp.175-181
    • /
    • 2009
  • All of the military aircrafts in Korea Air Force are administered and operated together in the same system regardless of whether they are equipped with the data communication capability or not. The absence of the data communication capability in some of the aircrafts might increase whole kill chain hour at the point of the Network Centric Warfare achievement. Network synergy effects cannot also be desired if the section which is not connected to the network influences to the whole tactical network. Equipping aircrafts with the data communication capability could be done by upgrading the aircrafts, but resulting in high costs and long updating time. This paper is a research about the design and implementation of the UMPC based Data Link System to aircrafts that do not have the data communication capability. The proposed system grafts the UHF-based wireless modem technology and the aircraft flight mission support software onto the off-the-shelf UMPC and GPS system. The employed UHF radio equipment allows communicating tactic data with another aircrafts on the air, the ground control point, and even the Tactical Air Control Party(TACP) control vehicle that achieve missions with aircrafts. It thereby increases such capabilities as navigation aid, situation awareness, quick target identification and attack. We also applied Closed Air Support(CAS) scenarios, which is very close to the real environment, to the experiments of the proposed system. The experimental results show that the proposed system could support the data communication capability effectively and the flight mission at low costs of money and time.

Research for Space Activities of Korea Air Force - Political and Legal Perspective (우리나라 공군의 우주력 건설을 위한 정책적.법적고찰)

  • Shin, Sung-Hwan
    • The Korean Journal of Air & Space Law and Policy
    • /
    • v.18
    • /
    • pp.135-183
    • /
    • 2003
  • Aerospace force is a determining factor in a modem war. The combat field is expanding to space. Thus, the legitimacy of establishing aerospace force is no longer an debating issue, but "how should we establish aerospace force" has become an issue to the military. The standard limiting on the military use of space should be non-aggressive use as asserted by the U.S., rather than non-military use as asserted by the former Soviet Union. The former Soviet Union's argument is not even strongly supported by the current Russia government, and realistically is hard to be applied. Thus, the multi-purpose satellite used for military surveillance or a commercial satellite employed for military communication are allowed under the U.S. principle of peaceful use of space. In this regard, Air Force may be free to develop a military surveillance satellite and a communication satellite with civilian research institute. Although MTCR, entered into with the U.S., restricts the development of space-launching vehicle for the export purpose, the development of space-launching vehicle by the Korea Air Force or Korea Aerospace Research Institute is beyond the scope of application of MTCR, and Air Force may just operate a satellite in the orbit for the military purpose. The primary task for multi-purpose satellite is a remote sensing; SAR sensor with high resolution is mainly employed for military use. Therefore, a system that enables Air Force, the Korea Aerospace Research Institute, and Agency for Defense Development to conduct joint-research and development should be instituted. U.S. Air Force has dismantled its own space-launching vehicle step by step, and, instead, has increased using private space launching vehicle. In addition, Military communication has been operated separately from civil communication services or broadcasting services due to the special circumstances unique to the military setting. However, joint-operation of communication facility by the military and civil users is preferred because this reduces financial burden resulting from separate operation of military satellite. During the Gulf War, U.S. armed forces employed commercial satellites for its military communication. Korea's participation in space technology research is a little bit behind in time, considering its economic scale. In terms of budget, Korea is to spend 5 trillion won for 15 years for the space activities. However, Japan has 2 trillion won annul budget for the same activities. Because the development of space industry during initial fostering period does not apply to profit-making business, government supports are inevitable. All space development programs of other foreign countries are entirely supported by each government, and, only recently, private industry started participating in limited area such as a communication satellite and broadcasting satellite, Particularly, Korea's space industry is in an infant stage, which largely demands government supports. Government support should be in the form of investment or financial contribution, rather than in the form of loan or borrowing. Compared to other advanced countries in space industry, Korea needs more budget and professional research staff. Naturally, for the efficient and systemic space development and for the prevention of overlapping and distraction of power, it is necessary to enact space-related statutes, which would provide dear vision for the Korea space development. Furthermore, the fact that a variety of departments are running their own space development program requires a centralized and single space-industry development system. Prior to discussing how to coordinate or integrate space programs between Agency for Defense Development and the Korea Aerospace Research Institute, it is a prerequisite to establish, namely, "Space Operations Center"in the Air Force, which would determine policy and strategy in operating space forces. For the establishment of "Space Operations Center," policy determinations by the Ministry of National Defense and the Joint Chief of Staff are required. Especially, space surveillance system through using a military surveillance satellite and communication satellite, which would lay foundation for independent defense, shall be established with reference to Japan's space force plan. In order to resolve issues related to MTCR, Air Force would use space-launching vehicle of the Korea Aerospace Research Institute. Moreover, defense budge should be appropriated for using multi-purpose satellite and communication satellite. The Ministry of National Defense needs to appropriate 2.5 trillion won budget for space operations, which amounts to Japan's surveillance satellite operating budges.

  • PDF

Design and Performance Analysis of Asymmetric Time Division Multiple Access Method for Improving Response Time and Throughput in Tactical Radio Communication (전술 무선통신망의 응답시간 및 처리량 개선을 위한 비대칭 다중접속기법 설계 및 성능분석)

  • Kwon, Yong Hyeun;Cha, Joong Hyuck;Kim, Dong Seong
    • Journal of the Korea Institute of Military Science and Technology
    • /
    • v.21 no.3
    • /
    • pp.361-369
    • /
    • 2018
  • This paper proposes a design of asymmetric time division multiple access method for tactical radio communication. Typical tactical radio communication has a limited execution of transmission, because uplink message requires more extended response time than downlink message. In order to solve this problem, this paper analyzes operational environment of Korean tactical radio communication and proposes an asymmetric TDMA based on it for performance of tactical communication. The simulation model is used to investigate constraints of real experiments for proving effectiveness of the proposed approach. Simulations results show that the proposed scheme outperforms the conventional scheme in terms of throughput, response time, and delay.

Target Performance Analysis of Tactical Voice Communication on VHF Narrow-band in Combat Network Radio System (전투무선체계(CNRS) VHF 협대역 전술음성통신 목표 성능 분석)

  • Kim, JaeUk;Park, Joonhah;Lee, Chulho;Lee, Byungkyu;Jung, Hayeon
    • Journal of the Korea Institute of Military Science and Technology
    • /
    • v.24 no.1
    • /
    • pp.107-114
    • /
    • 2021
  • By analyzing the voice communication performance of the existing tactical FM radios, the performance target of the newly developing TICN combat network radio system VHF band tactical voice communication waveform was derived. In addition, a vocoder and modulation method that can satisfy the performance target and additional requirements are presented, and the expected voice communication quality is analyzed.