This paper focuses on analyzing the modern warfare and weapon systems supported by improved GPS informations. The GPS capability was investigated through the real experimental test for verifying the most recent GPS features under its modernization processing. And then it was verified that such capabilities, accuracy and availability, of a typical L1, C/A code GPS receiver are equivalent to the military receiver's ones. It was also sure that the influence of GPS improved informations on NCW(Network-Centric Warfare), PGM(Precision Guided Munition) and C4SIR(Command, Control, Communications, Computers, Intelligence, Surveillance and Reconnaissance) should be increased and the modern warfare may be strongly dependent on GNSS informations.
This paper is to investigate propagation path characteristics of GPS potential jamming signal. To do this, the spherical ground diffraction model is applied to the potential jamming scenario referred to the GPS jamming events occurred in recent years. The fundamental theory on the propagation path loss is discussed and a specific model is applied to several vehicles types which have own heights of antennas in order to compare their propagation path loss values at same 2-D location. The transmitting powers are appropriately given as the ordinary GPS jamming events. And then the received powers in dBW are obtained with given transmitting powers and the estimated total loss. The result of received jamming power at various locations due to the given scenario was distinct. For example, propagation loss values were estimated as -147 ~ -142dBW and -167 ~ -162dBW in 106W and 104W, respectively. This computation result of the loss can be seriously considered with the tolerable jammer power against L1- C/A GPS receiver under any real jamming situations.
난중일기에 나타난 지명에 대해 현재의 행정지명과 위치는 대부분 확인되었다. 그럼에도 불구하고 명량해전 이후 한반도 서남해안을 항해하면서 이순신과 조선수군이 체류했던 장소 중 1597년 10월 11일 일기에 기록된 안편도의 현재의 지명과 위치가 어디인지 번역자 또는 학자들 간에 의견이 다를 뿐 아니라, 아직까지도 정확하게 확인되지 않고 있다. 이 연구는 안편도로 추정되어 온 기존의 장소에서 관찰한 지형지물의 방향과 위치가 실제 위치와 방향을 비교하여 얼마나 일치하는지를 분석하였고, 연구자들이 새롭게 탐사한 섬과 산에서 관찰한 지형지물의 방향과 위치가 실제 안편도와 얼마나 일치하는지를 분석하고 평가하였다. 그 결과 난중일기에 기록된 안편도는 현재의 안좌도에 있는 매봉산임을 확인하였다.
In this paper, the electromagnetic (EM) wave absorbers using TiO2 as a dielectric material with chlorinated polyethylene (CPE) were investigated in W-band radio frequencies. We compared the relative permittivity with reflectionless curve and the absorption properties of samples containing 40 wt.%, 50 wt.%, 60 wt.%, 70 wt.%, and 80 wt.% TiO2. It is possible to realize a complex relative permittivity satisfying the reflectionless condition by choosing composition ratio of TiO2. The optimized composition ratio of TiO2 for the maximum absorption property is about 70 wt.%. As a result, we have confirmed the realization of an EM wave absorber with a high absorption property in W-band radio frequencies.
It has been recognized that the risk from the vulnerability of GPS can lead to the extreme damage in the infrastructure of the civil and military in recent years. As an example, the intentional interference to GPS signal, named GPS jamming, was really performed to misguide GPS guided weapons during Iraq war in 2003, and the fact has also followed by the serious issues on GPS in civilian community. In the modernized military society, the navigation warfare(NAVWAR) based on the GPS jamming has been emerged and introduced as a military operation. The intentional interference to the future global navigation satellite system(GNSS) involving GPS must be also an important issue to civilian users in near future. This study is focused on the fundamental research prior to the research on "Potential principle of NAVWAR" under NAVWAR of the future warfare. In this paper, we would study on the investigation of NAVWAR based on electronic warfare(EW) and analyze characteristics of the jamming against GNSS's receivers. Then the general mechanism on GNSS jamming is proposed.