• Journal of Aerospace System Engineering
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• v.8 no.2
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• pp.40-48
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• 2014

In this paper, a prototype of GPS jammer localization system for precise landing is developed. The jammer localization system consists of the four jamming signal receivers for collecting RF signal, one central tracking station for estimating jammer position, and one monitoring station for displaying estimated position on the map. In order to estimate jammer location TDOA and AOA algorithm are introduced, and the function and design parameters of the developed prototype are proposed. CW, DSSS, Swept CW jamming signals were generated and used. From the results, it can be confirmed that developed system meets the performance goal.

• Journal of Advanced Navigation Technology
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• v.15 no.6
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• pp.962-969
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• 2011

This paper proposes the DOA estimation method based on TDOA/AOA for jammer localization method in GBAS environment. The proposed method can effectively estimate DOA of jamming signal as the range for DOA estimation is reduced remarkably by using DOP and 1st approximate solution using TDOA measurements only. Through the proposed method, more precise DOA can be obtained and the performance of jammer localization is increased simultaneously. Also, the effectiveness of proposed method will be confirmed through the simulated results.

• Journal of Institute of Control, Robotics and Systems
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• v.20 no.1
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• pp.101-105
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• 2014

For a localization system, the TDOA (Time Difference of Arrival) measurement and AOA (Angle of Arrival) measurement are often used for estimating target's positions. Although it is known that the accuracy of TDOA based localization is superior to that of AOA based one, it may have a poor vertical accuracy in bad geometrical conditions. This paper, therefore, proposes a localization algorithm in which the vertical position is estimated by AOA measurements and the horizontal one is estimated by TDOA measurement in order to achieve high 3D-location accuracy. And this algorithm is applied to a GPS jammer localization systems because it has a large value of the DOP (Dilution of Precision) when the jammer is located far away from the system. Simulation results demonstrate that the proposed hybrid TDOA/AOA location algorithm gives much higher location accuracy than TDOA or AOA only location.

• Journal of Positioning, Navigation, and Timing
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• v.6 no.1
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• pp.9-15
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• 2017

In this paper, results of a jammer detection and localization system operation are given. The system consists of receiver stations, a central tracking station, and a monitoring station and it was developed by our institute in 2014. Through real-time tests, it is confirmed that the developed system has an ability to estimate the location of interference sources with an accuracy of 50 m (CEP) even they was 10 km away. After verification, this system was installed in Incheon International Airport and operating results are being monitored by the airport and our institute continuously. In this year, there were some events that jamming signals were received from North Korea, so the data were analyzed and given here.

• Journal of Advanced Navigation Technology
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• v.15 no.6
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• pp.1241-1249
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• 2011

There are TOA, TDOA and AOA method to estimate the position of the electromagnetic wave transmitter by using the multiple receivers at the fixed position. Among these methods, AOA method is suitable for the jammer localization system. Because TOA method can be adopted for the clocks of the transmitter and the receiver are synchronized each other, and TDOA method can be only adopted for a broad-band jamming signal. This paper, therefore, analyzes the characteristics of the AOA measurements and the sensitivity of the positioning performance according to the system design parameters. Based on the analyzed results, the jammer localization system to meet the desired performance is designed, and it has been checked that the positioning error for the jammer located at a distance of 10km is lower than 38m through the simulation results.

• Journal of Advanced Navigation Technology
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• v.19 no.6
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• pp.524-533
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• 2015

In this paper, results for an installation and operation of a GPS jammer localization system were analyzed. The jammer localization system was developed by Korea Aerospace Research Institute and it consists of 4 Receiver Stations, a Central Tracking Station, and a Monitoring Station. The system was installed at Incheon International Airport in November 2014; each Receiver Stations were installed at rooftop of buildings apart from 4km, and the Central Tracking Station and a Monitoring Station were installed at indoor. Results of the operation can be monitored through web-browser in real-time, Korea Aerospace Research Institute and Incheon International Airport Corporation are continuously monitoring them. So far, there is no jamming signal which affects GPS receivers around the airport, however, some abnormal signals were frequently received at Receiver Stations. Therefore, the characteristics of those signals were also analyzed in this paper.

• Journal of Positioning, Navigation, and Timing
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• v.3 no.2
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• pp.45-51
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• 2014

GNSS has the disadvantage of being vulnerable to jamming, and thus, the necessity of jamming countermeasure techniques has gradually increased. Jamming countermeasure techniques can be divided into an anti-jamming technique and a jammer localization technique. Depending on the type of a jammer, applicable techniques and performance vary significantly. Using an appropriate jamming countermeasure technique, the effect of jamming on a GNSS receiver can be attenuated, and prompt action is enabled when estimating the location of a jammer. However, if an inappropriate jamming countermeasure technique is used, a GNSS receiver may not operate in the worst case. Therefore, jammer identification is a technique that is essential for proper action. In this study, a technique that identifies a jammer based on template matching was proposed. For template matching, analysis of a received jamming signal is required; and the signal analysis was performed using a spectral correlation function. Based on a simulation, it was shown that the proposed identification of jamming signals was possible at various JNR.

• International Journal of Control, Automation, and Systems
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• v.5 no.2
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• pp.200-207
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• 2007

The passive direction finding cross localization method is widely adopted in passive tracking, therefore there will exist masses of false intersection points. Eliminating these false intersection points correctly and quickly is a key technique in passive localization. A new method is proposed for passive locating and tracking multi-jammer target in this paper. It not only solves the difficulty of determining the number of targets when masses of false intersection points existing, but also solves the initialization problem of elastic network. Thus this method solves the problem of multi-jammer target correlation and the elimination of static false intersection points. The method which dynamically establishes multiple hypothesis trajectory trees solves the problem of eliminating the remaining false intersection points. Simulation results show that computational burden of the method is lower, the elastic network can more quickly find all or most of the targets and have a more probability of locking the real targets. This method can eliminate more false intersection points.

• Journal of the Korea Institute of Military Science and Technology
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• v.15 no.6
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• pp.729-737
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• 2012

In case that multiple jammers are transmitting the signals which are the same type a general algorithm based on TDOA method cannot estimate the positions of multiple jammers because there are many TDOA measurements including true and false values. This paper, therefore, designs a new algorithm based on TDOA method to localize multiple jammers. In this algorithm, TDOA measurements are obtained by rotating the reference sensor, and then the positions of multiple jammers can be estimated by detecting congregated point among the multiple estimated positions from TDOA measurements. Through computer simulations, it is verified that this algorithm localizes the multiple jammers well. The performance of the algorithm are also analysed by changing the distance between sensors and jammer, and sampling frequency.

• Journal of Advanced Navigation Technology
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• v.17 no.6
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• pp.616-624
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• 2013

When jamming signal is received, there would be malfunctions in GPS-based precise location systems. Especially, in aviation fields, these malfunctions may lead to more serious damages. Naturally, there are some research results about the prevention or location method for one jammer, but it is hard to identify and obtain measurements when multiple and various type signals are received. Therefore, we propose a method of identification and measurements acquisition algorithm in order to localize the multiple jammers which transmit CW, DSSS and SCW type signals. Also, a computer simulation is carried out so as to validate the feasibility of the proposed method by using MATLAB. From the simulation results, it is confirmed that the proposed method successfully identified the signal type and acquired the measurements of CW, DSSS and SCW type signals.