A Study on Propagation Path Characteristics of GPS Potential Jamming Signal Based on Spherical Ground Diffraction Loss

Kwang-Soob Ko 해양환경안전학회 2013 海洋環境安全學會誌 Vol.19 No.3

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.

A Study on Propagation Path Characteristics of GPS Potential Jamming Signal Based on Spherical Ground Diffraction Loss

고광섭 해양환경안전학회 2013 海洋環境安全學會誌 Vol.19 No.3

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 10^6W and 10^4W, 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.

A Study on Propagation Path Characteristics of GPS Potential Jamming Signal Based on Spherical Ground Diffraction Loss

Ko, Kwang-Soob The Korean Society of Marine Environment and safet 2013 해양환경안전학회지 Vol.19 No.3

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 $10^6W$ and $10^4W$, 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.

24 ㎓ 이하 도심/부도심의 클러터 손실 측정 및 분석

강영흥(Young-Heung Kang),이행선(Haeng-Seon Lee),박성원(Sung-Won Park),이일용(Il-Yong Lee),임종혁(Jong-Hyuk Lim),윤대환(Dea-Hwan Yoon) 한국전자파학회 2018 한국전자파학회논문지 Vol.29 No.6

최근 국립전파연구원에서는 5G 이동통신 도심/부도심 지역에서 빌딩에 의한 클러터 손실을 예측하기 위해 3, 6, 10, 18, 24 ㎓ 대역에서 전파측정을 수행하였다. 본 연구에서는 송신안테나 높이가 85 m일 때, 도심과 부도심환경에서 주파수에 따라 측정된 클러터 손실을 비교하며, ITU-R P.2108 예측모델과의 오차를 평가하였다. 도심이나 부도심 지역에서 주파수가 높을수록 클러터 손실이 크게 나타나며, 도심 지역에서의 클러터 손실은 부도심 지역보다 더욱 강한 클러터 손실을 보이지만, ITU-R P.2108 예측 모델보다 낮은 클러터 손실을 얻어졌다. 결론적으로 측정된 데이터로부터 송신 안테나가 85 m로 높은 경우 도심/부도심 지역에서 클러터 손실에 대한 데이터를 예측모델에 반영하여 클러터 손실 예측모델을 좀 더 개선시켜 나갈 필요가 있다. Recently, measurements on clutter loss due to buildings in urban/suburban areas at 3, 6, 10, 18, and 24 ㎓ have been performed by the Radio Research Agency with the purpose of predicting the clutter loss close to actual urban/suburban propagation for 5G mobile communication. In this work, we have compared the urban clutter loss to suburban clutter loss for a transmit antenna height of 85 m. Furthermore, we have estimated the error between the predicted loss as per ITU-R P.2108 and the measured clutter loss. Our results indicate that for higher frequencies, the measured clutter loss in urban/suburban areas is higher and so lower than the predicted clutter loss. In conclusion, it is necessary to improve the prediction model for clutter loss by taking into account the measured clutter loss in urban/suburban areas in the prediction model.

UHF 대역 장거리 항공 통신 시험의 전파 손실 분석

장민수(Min-soo Chang),김규환(Kyoo-hwan Kim),김재환(Jae-hwan Kim),이재문(Jae-moon Lee),황찬호(Chan-ho Whang) 한국산학기술학회 2018 한국산학기술학회논문지 Vol.19 No.8

본 논문에서는 지상 수신기와 항공기 탑재 송신기 간의 장거리 통신시험을 통해 UHF 대역의 전파 수신세기를 측정하고 그 결과를 분석하였다. 지상 수신기는 제주도 해발 1,100m 지점에 위치시키고 항공 탑재 송신기는 지상 수신기로부터 150km에서 220km 거리를 3.5km 이상의 고도로 비행하며 시험을 수행하였다. 이 경우 지상 수신기와 항공 송신기는 가시선(LOS ; Line of Sight)이 확보되는 환경이므로 자유공간손실(FSL ; Free Space Loss)을 토대로 결과를 예측하고 분석을 하는 경우가 일반적이다. 하지만 본 시험의 경우 지상 수신기와 항공 송신기 사이에 해수면이 존재하고, 장거리 통신 환경으로 인하여 반사면에 대한 입사각이 매우 작은 조건으로 직접 파의 자유공간손실 만으로는 정확한 예측 및 분석이 불가능하다. 따라서 주변에 장애물이 없고 두 안테나 사이 가시선이 확보되는 조건을 고려하여 평면 반사 모델과 구면 대지 반사 모델을 토대로 경로 손실을 예측하고 실제 시험결과와 비교하였다. 비교 결과, 구면 대지 반사모델에서 예측한 전파경로 손실 값과 실제 측정결과가 매우 유사한 특성을 보였다. In this paper, we measured the propagation path loss by a ground to air flight communication test at UHF band and analyzed the results. The ground receiving terminal was located at 1,100m above sea level in Cheju Island and the airborne transmit terminal flew at an altitude of 3.5km from 150 to 220km from the ground terminal. In this case, the ground terminal and the airborne terminal are on the Line of Sight. Therefore loss in this communications environment can be predicted based on Free Space Loss. However, in this test, the sea level exists between two terminals, and due to the very small angle of incidence on the reflecting surface due to the long-range communication environment, it is not possible to accurately predict the loss of free space only. Therefore, considering that there are no surrounding obstacles and that a line of sight is secured between the end of two terminals, we applied a plane earth reflection model and a spherical earth reflection model to estimate the propagation path loss and compared with the actual test results. As a result of the comparison, the predicted propagation path loss by a spherical earth reflection model were quite similar to the actual test values.

Propagation Model of High-Power Electromagnetic Pulse by Using a Serial–Parallel Resistors Circuit

Kun-A Lee,Kwang-Cheol Ko IEEE 2014 IEEE transactions on plasma science Vol.42 No.10

<P>The risk of high power electromagnetic (HPEM) pulse is dramatically increasing as the output of HPEM pulse increases and the affected electronic devices becomes smaller [1], [2]. There are largely two ways of coupling HPEM pulse: 1) front door coupling, which is through antennas and sensors to receive signals and 2) back-door coupling, which is through an unintended way, such as punctures and slots. In this paper, we modeled the loss phenomenon of HPEM pulse which happens when HPEM pulse radiated from HPEM system propagates to the receiving antenna. The loss circuit consists of serial-parallel resistors, each value of resistor is formularized as distance. Our modeling consists of two parts: 1) one-stage model, which means initial value for various applications and 2) nth-stage model, which means additional distances. Therefore, we could figure out the effect of HPEM on antenna as the propagation distance changes. After the due simulations, we confirm our hypothesis as the HPEM pulse which reaches to receiving antenna is consistent with the existing theory. This circuit modeling is very remarkable in that it understands two different HPEM system and propagation/receiving antenna as one whole system.</P>

이음5G 4.7 GHz 대역에서 건물간 전달손실 측정 및 분석

장원,김동우,조병록,오순수 한국전자파학회 2023 한국전자파학회논문지 Vol.34 No.7

A demand-based deployment strategy has been recently proposed for e-Um5G in the industrial market. This study measured the transmission loss between buildings at a frequency of 4.7 GHz to initiate small cell deployment in certain areas. A local average apparatus was utilized to remove fading effects, and data were acquired at discrete points one or two meters apart. The transmission losses for buildings 39 m and 95 m from the transmitter were 56.6 dB and 69.1 dB, respectively, excluding free-space loss. The transmission loss was found to be sensitive to building structure and transmitter location, as the loss for a building 39 m away decreased to 49.5 dB when the transmitter was moved closer to the building entrance. The measured results were analyzed in terms of the ITU-R SG3 (International Telecommunication Union-Radiocommunication Sector, Study Group 3) definition of building entry loss and can be used for frequency sharing and building-level small cell deployment in the e-Um5G frequency band.

메탄-프로판 층류 부상화염의 열손실 자기진동에 관한 연구

김경호(Gyoung-Ho Kim),박정(Jeong Park),권오붕(Oh Boong Kwon),김정수(Jeong Soo Kim),배대석(Dae Seok Bae) 한국연소학회 2011 KOSCOSYMPOSIUM논문집 Vol.- No.43

Flame stability map for a nozzle diameter of 0.35㎜ has been experimentally investigated to observe self-exicitations and flame in laminar lifted flames with the mixed fuel of propane and methane. The observed self-excitations can be classified into two:heat-loss-induced self-excitation and a combined form of buoyancy-induced self-excitation due to a flame flicker and heat-loss-induced self-excitations. It is found that the self-excitation with excessively low frequency(<0.1㎐) is caused by heat loss from premixed wings to the trailing diffusion flame. A functional dependencies of Strouhal number upon their related physical parameters are presented for individual self-excitations. It is also seen that the buoyancy-induced self-excition frequency with exit velocity increase in triple flame propagation and then decrease in flame front propagation.

Empirical millimeter-wave wideband propagation characteristics of high-speed train environments

Park, Jae-Joon,Lee, Juyul,Kim, Kyung-Won,Kwon, Heon-Kook,Kim, Myung-Don Electronics and Telecommunications Research Instit 2021 ETRI Journal Vol.43 No.3

Owing to the difficulties associated with conducting millimeter-wave (mmWave) field measurements, especially in high-speed train (HST) environments, most propagation channels for mmWave HST have been studied using methods based on simulation rather than measurement. In this study, considering a linear cell layout in which base stations are installed along a railway, measurements were performed at 28 GHz with a speed up to 170 km/h in two prevalent HST scenarios: viaduct and tunnel scenarios. By observing the channel impulse responses, we could identify single- and double-bounced multipath components (MPCs) caused by railway static structures such as overhead line equipment. These MPCs affect the delay spread and Doppler characteristics significantly. Moreover, we observed distinct path loss behaviors for the two scenarios, although both are considered line-of-sight (LoS) scenarios. In the tunnel scenario, the path loss exponent (PLE) is 1.3 owing to the waveguide effect, which indicates that the path loss is almost constant with respect to distance. However, the LoS PLE in the viaduct scenario is 2.46, which is slightly higher than the free-space loss.

TETRA 기반 고속철도 열차무선의 전파 경로손실 특성

배성호(Bae, Sung-Ho),최규형(Choi, Kyu-Hyoung) 한국산학기술학회 2013 한국산학기술학회논문지 Vol.14 No.6

경부고속철도 2단계 구간에 도입된 열차무선시스템은 TETRA 기반으로 851MHz 대의 주파수를 사용하고 있다. 이와 같은 열차무선시스템에서 운행중인 차량과 지상과의 끊임없는 정보송수신을 위하여 전파 경로손실을 감 안한 기지국 설계가 필수적이다. 본논문에서는 고속철도 선로에서의 측정데이터를 토대로, 열차무선의 전파 경로손실 을 정량적으로 분석하였다. 열차무선 기지국 설계에서는 자유공간 전파 경로손실모델 및 Okumura-Hata모델이 사용되 고 있는데, 이 모델들에 의한 예측치는 현장측정치보다 10dB 이상 작거나 20dB 이상 크게 나타남에 따라 고속철도 열차무선의 경로손실 예측에는 적합하지 않은 것으로 나타났다. 측정결과를 log-distance 경로손실모델에 적용하여 회 귀분석을 수행한 결과 경로손실지수는 2.8~3.2의 범위로 나타났으며, 이 결과는 향후 고속철도 열차무선에서의 전파 경로손실 예측에 적용할 수 있다. Train radio system has been constructed in the second stage of Kyung-bu high speed railway adopting TETRA(Terrestial trunk radio) standard at 851MHz frequency band. The base stations of the train radio system should be located along railway track to ensure seamless communication between train and wayside taking the path loss of train radio propagation into consideration. This paper provides a quantitative analysis of the path loss characteristics based on the measurement results of the train radio propagation along the high speed railway. The free space propagation model and Okumura-Hata model are generally used for base station design, but they predicted 10dB lower or 20dB higher than the measured path loss. Linear regression of the field measured data by applying the log-distance model shows path loss exponent is in the 2.8-3.2 range, which can be used to predict the path loss of the train radio propagation.