• Journal of the Institute of Electronics Engineers of Korea SP
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• v.43 no.6 s.312
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• pp.105-112
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• 2006

To improve the performance of identification for radars in an ES(Electronic warfare Support) system, it is necessary to estimate scan characteristics as well as the basic identification parameters such as frequency, pulse repetition interval and pulse width of radars. This paper presents the method of estimating the scan period and the scan beam width of circular scanning radars. The proposed method estimates the scan period using the quality of the autocorrelation of a periodic signal. And, it estimates the scan beam width using the linear interpolation and the proposed method of estimating the scan period. Simulation results are presented to show the performance of the proposed method.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.41 no.6
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• pp.611-619
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• 2016

Success in modern war depends on electronic warfare. Therefore, It is very important to identify the kind of Radar PRI modulations in a lot of Radar electromagnetic waves. In this paper, I propose an algorithm to identify Linear up Sliding PRI, Non-Linear up Sliding PRI and Linear Down Sliding PRI, Non-Linear Down Sliding PRI among many Radar pulses. We applied not only the TDOA(Time Difference Of Arrival) concept of Radar pulse signals incoming to antennas but also a rising and falling curve characteristics of those PRI's. After making a program by such algorithm, we input each 40 data to those PRI's identification programs and as a result, those programs fully processed the data in according to expectations. In the future, those programs can be applied to the ESM, ELINT system.

• Journal of the Institute of Electronics and Information Engineers
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• v.49 no.10
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• pp.83-88
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• 2012

The pitch searching is a very important process in a vocoder. Generally, the method of pitch searching method is used by highlighting the periodicity, where a correlation is identified with the signal by changing the interval of two pulses. When the correlation value is highest, the pitch can be found by the pulse interval because it is the repetition interval with most striking period. There are many methods to solve this problem and search the pitch by dividing a frame into many subframes, but there is too much calculation to solve. A method in this paper is suggested to vary the number of subframes by predicting the amplitude change rate in a frame. If this method is applied, the general pitch searching performance will be improved because the accuracy may be enhanced without affecting the sound quality in the synthesized signal after parameter transmission; and the pitch searching time may be reduced.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.3
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• pp.34-41
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• 2014

Through applying hostile radar signals that use stagger PRI to PRI transform in real time, we can analyze stagger PRI and calculate the future TOA for active cancellation by using measured TOA and estimated PRI. We shows the effect of the errors that are contained in PRI and measured TOA. Then, it will suggest the technique to improve the accuracy of estimated PRI and the TOA averaging method for reducing the effect of measured TOA error. Finally, we will show that accuracy of estimated future TOA that is calculated by proposed scheme is higher than that of future TOA that is simply calculated with TDOA and newest TOA through comparing RMSE performance.

• Journal of the Korea Institute of Military Science and Technology
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• v.13 no.4
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• pp.569-576
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• 2010

Jamming simulator has developed for the purpose of the test and evaluation on the electronic protection capabilities of the tracking radar onboard ship. This simulator has the capabilities to generate and radiate the jamming signals against the radar as well as those to receive, analyze and identify the radar signals at a real sea environment. The limited space of ship superstructure has led to the serious distortion caused by the ring around phenomenon that some sidelobes of the jamming beams were coming back to the receiving antenna. In this paper, we have proposed the methods to eliminate the ring around. First, we have inserted the groove metal screen between transmitting and receiving antennas. Second, we have used the PRI(Pulse Repetition Interval) tracking loop to control the switching timing of the input radar and the output jamming signal. Finally, we have demonstrated the performance and effectiveness of the proposed methods through the sea trial.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.4
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• pp.707-714
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• 2016

Active driving safety systems for vehicle, such as the front collision avoidance, lane departure warning, and lane change assistance, have been popular to be adopted to the compact car. For improving performance and competitive cost, FMCW radar has been researched to adopt a phased array or a multi-beam antenna, and to integrate the front and the side radar. In this paper we propose several efficient methods to implement the signal processing module of FMCW radar system using low cost DSP. The pulse width modulation (PWM) based analog conversion, the approximation of time-eating functions, and the adoption of vector-based computation, etc, are proposed and implemented. The implemented signal processing board shows the real-time performance of 1.4ms pulse repetition interval (PRI) with 1024pt-FFT. In real road we verify the radar performance under real-time constraints of 10Hz update time.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.47 no.4
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• pp.73-85
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• 2010

In dense electronic warfare signal environments, the conventional radar identification methods based on the basic parameters such as frequency, pulse width, and pulse repetition interval are confronted by the problem of identification ambiguity. To overcome this critical problem, a new approach introducing scan pattern of radars has been presented. Researches on new identification methods, however, suffer from a practical problem that it is not easy to secure the many radar signals including various scan pattern information and operation parameters. This paper presents a modeling method of radar signals with which we can generate radar signals including various scan pattern types according to the parameters determining the variation pattern of received signal strength. In addition, with the radar signals generated by the proposed model we analyze their characteristics according to the location of an electronic warfare support (ES) system.

• Journal of the Institute of Electronics and Information Engineers
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• v.52 no.4
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• pp.184-193
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• 2015

Passive Surveillance System based on the TDOA detects the emitter position in the air using TOA of pulses comprising emitter signal from multiple receivers. In case that PRI of pulses from the emitter is not enough big in comparison with the distance among receivers, it causes the ambiguity problem in selecting proper pulse pairs for TDOA emitter geolocation. In this paper, a novel ambiguity resolution method of radar pulses is presented by using genetic algorithm after changing ambiguity problem into optimization problem between TDOA of received pulses from each receiver and emitter position. Simulation results are presented to show the performance of the proposed method.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.38 no.3
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• pp.249-255
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• 2002

This paper describes on the extraction of ship's real-time movement information using a combination full-function ARPA radar and ECS system that displays radar images and an electronic chart together on a single PC screen. The radar target extractor(RTX) board, developed by Marine Electronics Corporation of Korea, receives radar video, trigger, antenna bearing pulse and heading pulse signals from a radar unit and processes these signals to extract target information. The target data extracted from each pulse repetition interval in DSPs of RTX that installed in 16 bit ISA slot of a IBM PC compatible computer is formatted into a series of radar target messages. These messages are then transmitted to the host PC and displayed on a single screen. The position data of target in range and azimuth direction are stored and used for determining the center of the distributed target by arithmetic averaging after the detection of the target end. In this system, the electronic chart or radar screens can be displayed separately or simulaneously and in radar mode all information of radar targets can be recorded and replayed In spite of a PC based radar system, all essential information required for safe and efficient navigation of ship can be provided.

• The Journal of the Acoustical Society of Korea
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• v.31 no.7
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• pp.419-426
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• 2012

The pitch searching is a vital process in a vocoder. Generally, the method of pitch searching is employed after highlighting the periodicity, where a correlation is identified with the signal by changing the interval of two pulses. When the correlation value reaches the peak, the pitch can be found by the pulse interval because it is the repetition interval with most striking period. However if the identified period happens to be one of half period, double period or triple period, this cannot be considered as the pitch period. Many methods were suggested to solve this problem. An inaccurate pitch could be obtained as well, when there is an interval where signal amplitude is not constant but varies abruptly in the frame. To solve this matter, searching the pitch by dividing a frame into various subframes is adopted, but too much calculation has to be followed while it leads the correct value. This paper suggests an algorithm to resolve these two problems. First, to search the pitch after advance correction of the signal energy level with an estimated overall energy change ratio in the frame before pitch search to reduce half period, double period and triple period is suggested. Second, to vary the number of subframes by predicting the amplitude change rate in the frame by the energy ratio obtained by the above-mentioned method is advised. If these two methods are applied, the pitch searching time can be reduced and the general pitch searching performance can be improved without affecting the sound quality in the synthesized signal.