• Journal of Positioning, Navigation, and Timing
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• v.12 no.3
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• pp.229-236
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• 2023

As the importance and dependency of the positioning, navigation, and timing (PNT) information provided by the radio navigation satellite service (RNSS) increases, the vulnerability of RNSS to jamming can lead to significant risks. The signal design under the consideration of anti-jamming performance helps to provide service which is robust to jamming environment. Therefore, it is necessary to evaluate the jamming robustness performance during the design of new signals. In this paper, we introduce figures-of-merit (FoMs) that can be used for an anti-jamming performance analysis of designed signals of interest. We then calculate the FoMs, such as the quality factor (Q factor), tolerable jamming-to-signal ratio (tolerable J/S), and range to jammer (d) for legacy RNSS signals and analyze the results. Finally, based on the results of the analysis, we derive waveform design conditions to obtain good anti-jamming performance. As a result, this paper shows that the waveforms with wide bandwidth leading to good spectral efficiency provide strong anti-jamming performance.

• Journal of Positioning, Navigation, and Timing
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• v.4 no.1
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• pp.17-23
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• 2015

With the increase in the risk of GPS jamming, the development and application of anti-jamming GPS techniques have been actively performed. As the objective performance verification of developed techniques is important, equipment development for verification and discussion on anti-jamming performance test method and procedure have also been conducted. However, most tests are related to the specification of equipment and therefore detailed procedure of the performance verification of an anti-jamming system needs to be developed. In this study, requirements for anti-jamming performance verification were described, and test configurations and performance evaluation items depending on three kinds of test methods (lab test, basic outdoor test, and chamber test) were suggested for anti-jamming performance verification.

• Journal of Satellite, Information and Communications
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• v.10 no.4
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• pp.136-140
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• 2015

In this paper, a comparative studies on the STAP and SFAP were performed, which are known as representative anti-jamming technology for adaptive array antenna. As a method of estimating the weighting vector for simulation, MMSE(Minimum Mean Square Error) algorithm was commonly used and the analyses of the simulation performance in various jamming environments were presented. Especially, performance comparison between STAP and SFAP according to the jamming power J/S(Jamming to Signal Power Ratio), performance comparison in the ratio of jamming bandwidth to signal bandwidth, and performance comparison of BER between STAP and SFAP were presented.

• Journal of the Korea Institute of Military Science and Technology
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• v.21 no.1
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• pp.115-123
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• 2018

In this paper, we consider the applicability of time-hopping(TH) systems for anti-jamming(AJ) communication. We first briefly summarize fundamentals of TH systems and several common jamming scenarios that have been considered in the literature. We then analyze the AJ performance of TH systems under those common jamming environments. From our simulation results, we reveal that among narrow band, partial band, broadband, and sweep jamming, partial band and sweep jamming are the best ones from jammer perspective. For the partial band jamming case, we show that the most effective bandwidth ratio and location are 50 % and 2.5-3.5 Ghz, respectively. For the sweep jamming case, we illustrate that the AJ performance of the TH system is enhanced when the sweep duration approaches to the bit duration. In addition, we pointed out that the most efficient jamming bandwidth ratio is 1/2. Finally, our results show that the TH-BPSK system greatly outperforms the TH-PPM counterpart.

• Journal of the Korean Institute of Telematics and Electronics
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• v.27 no.10
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• pp.1-9
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• 1990

The performance of noncoherent FH/FSK system in the presence of multitone jamming and noise is analyged. Random and the structured jammings are considered as a multitone jamming model. The probability density function is derived and then optimum decision rule is applied to determine error probability of each cases. As a result, error probabilities of random and structured multitone jamming are shown as a function of number of jamming tones, jamming to signal power ratio, jamming signal phase and one jamming tone power to signal power ratio under Worst-case Jamming interference. It is found that error probability is maximam when one jamming tone power to signal power ratio is 1. Also we know that error performance of random and structured jamming is almost equal.

• Journal of Institute of Control, Robotics and Systems
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• v.19 no.2
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• pp.152-157
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• 2013

In this paper, we represent the implementation and performance analysis of vector tracking loop based GPS receiver for jamming environment. The vector tracking loop navigation performance is compared by simulation with conventional tracking loop. The simulation results shows that vector tracking loop is more robust than conventional tracking loop in jamming environment. The vector tracking loop can gain 2dB in jamming performance capability over a conventional GPS receiver. Also, Anti-jamming performance of INS Doppler aiding and deep integration method are compared.

• Journal of Internet Computing and Services
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• v.23 no.1
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• pp.113-124
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• 2022

In wartime conditions, the communication system of military aircraft is exposed to jamming, and it is necessary to mount communication equipment with high anti-jamming performance in order to perform air operations smoothly even in an environment where jamming attempts are made. In this paper, we check in detail the jamming and anti-jamming technology that can be applied to wireless communication, and the data disclosed on the difference in specifications of the next-generation anti-jamming radio with frequency hopping method and the improvement of anti-jamming performance according to these changes. It was briefly analyzed within the scope. In addition, the points to be considered when designing a new domestic aircraft and the possibility of installing the next-generation anti-jamming communication equipment on the currently operating aircraft were confirmed, and the tactical usefulness of improving the anti-jamming capability of the next-generation anti-jamming communication equipment was confirmed.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.15 no.10
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• pp.868-878
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• 1990

Upon introducing satellite communication system to Korea, one of the important problems to cope with is the effect from the probable intentional interference I.e. jamming. In this paper we have investigated how much the performance of ordinary PSK signal and Directed Sequence Spread Spectrum PSK signal degrade by the effect of jamming in the satellite communication system. In analysis we have consider the M ary PSK signal and the liniter type nonlinear satellite transponder in an environment of uplink tone or noise jamming plus Gaussian noise and downlink Gaussian noise. Using the derived error rate equation we have evaluated the error performance of BPSK and QPSK systems and compared this with that of DS BPSK system. Form the results, we know that the nonlinear satellite system is degraded more severely by the effect of noise jamming than tone jamming and the effect of tone jamming on the error rate performance can be reduced more remarkably by increasing the process gain in DS BPSK system rather than increasing carrier to jamming noise power ratio in conventional BPSK system.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.15 no.9
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• pp.3444-3457
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• 2021

In the field of anti-jamming based on dynamic spectrum, most methods try to improve the ability to avoid jamming and seldom consider whether the jammer would perceive the user's signal. Although these existing methods work in some anti-jamming scenarios, their long-term performance may be depressed when intelligent jammers can learn user's waveform or decision information from user's historical activities. Hence, we proposed a hidden anti-jamming method to address this problem by reducing the jammer's sense probability. In the proposed method, the action correlation between the user and the jammer is used to evaluate the hiding effect of the user's actions. And a deep reinforcement learning framework, including specific action correlation calculation and iteration learning algorithm, is designed to maximize the hiding and communication performance of the user synchronously. The simulation result shows that the algorithm proposed reduces the jammer's sense probability significantly and improves the user's anti-jamming performance slightly compared to the existing algorithms based on jamming avoidance.