• KSII Transactions on Internet and Information Systems (TIIS)
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• v.16 no.3
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• pp.908-928
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• 2022

Multiple target tracking mainly focuses on tracking unknown number of targets in the complex environment of clutter and missed detection. The generalized labeled multi-Bernoulli (GLMB) filter has been shown to be an effective approach and attracted extensive attention. However, in the scenarios where the clutter rate is high or measurement-outliers often occur, the performance of the GLMB filter will significantly decline due to the Gaussian-based likelihood function is sensitive to clutter. To solve this problem, this paper presents a robust GLMB filter and smoother to improve the tracking performance in the scenarios with high clutter rate, low detection probability, and measurement-outliers. Firstly, a Student-T distribution variational Bayesian (TDVB) filtering technology is employed to update targets' states. Then, The likelihood weight in the tracking process is deduced again. Finally, a trajectory smoothing method is proposed to improve the integrative tracking performance. The proposed method are compared with recent multiple target tracking filters, and the simulation results show that the proposed method can effectively improve tracking accuracy in the scenarios with high clutter rate, low detection rate and measurement-outliers. Code is published on GitHub.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.33A no.3
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• pp.10-17
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• 1996

The performance of tau-dither loop (TDL) is evaluated for a direct-sequence spread-spectrum system in a multipath fading channel. The multipath fading channel is modeled as a two-ray rayleight fading channel. The code tracking perfomrance of TDL is analyzed in terms of tracking jitter and mean-tiem-to-lose-lick (MTLL). The tracking jitter performance is degraded while MTLL perfomrance is improved with increasing discriminator offset and decreasing power ratio of main to second paths. It is shown that for a large bit SNR, the effect of multipath fading becomes more significant. And it is also shown that tracking jitter and MTLL performance is less sensitive to delay spacing and discriminator offset for a small bit SNR than for a large bit SNR.

• Journal of Communications and Networks
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• v.12 no.3
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• pp.216-221
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• 2010

In this paper, we propose and develop a new algorithm for the principle subspace tracking by orthonormalizing the eigenvectors using an approximation of Gram-Schmidt procedure. We carry out a novel mathematical derivation to show that when this approximated version of Gram-Schmidt procedure is added to a modified form of projection approximation subspace tracking deflation (PASTd) algorithm, the eigenvectors can be orthonormalized within a linear computational complexity. While the PASTd algorithm tries to extracts orthonormalized eigenvectors, the new scheme orthonormalizes the eigenvectors after their extraction, yielding much more tacking efficiency. We apply the new tracking scheme for blind adaptive multiuser detection for non-stationary cellular CDMA environment and use extensive simulation results to demonstrate the performance improvement of the proposed scheme.

• The Journal of the Korea institute of electronic communication sciences
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• v.12 no.1
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• pp.61-68
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• 2017

In this paper, the coarse acquisition code (C/A code), for civil navigation, of the ranging codes for Global Positioning System (GPS) is studied, simulated and analyzed by using Matlab. We can see with the simulation results that the correctness of the method and feasibility, which is at simulation platform to further study on the real environment of GPS signal, can be confirmed. With using this results, we think, the complexity of tracking the satellite signal environment can be captured, and the performance of satellite receiver will be improved.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.22 no.3
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• pp.506-514
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• 1997

In this paper, we implement digital circuit of despreading delay lock loop for GPS receiver. The designed system consists of Epoch signal generator, two 13bit correlators which correlates the received C/A code and the locally generated C/A code in the receiver, the C/A code generator which generates C/A code of selected satellite, and the direct digital clock synthesizer which generates the clock of the C/A code generator to control the phase and clock rate, the clock controller, and the clock divider. The designed circuit has the function of the acquisition and tracking by the autocorrelation characteristics of Gold code. The controller generates each other control signals according to the correlation value. The designed circuit is simulated to verify the logic functional performance. By using the simulator STR-2770 that generates the virtual GPS signal, the deigned FPGA chip is verified the circuit performance.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.4 no.2
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• pp.417-426
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• 2000

In this paper, CE-CPSK(Constant Envelope Continuous Phase Shift Keying) modulated DS/SS(Direct Sequence Spread Spectrum) transceiver with 908 MHz carrier frequency and 1.5 MHz PN clock rate is proposed. To overcome the effect of nun-linear power amplifier, CE-CPSK modulation method which has the constant envelope and continuous phase characteristics is proposed. To analyze the DS/SS receiver performance with respect to code tracking loop, multipath fading channel is characterized as a two-ray Rayleigh fading channel. To compensate the demerit of analog delay locked loop, digital delay locked loop is employed for code tracking loop. Simulation and experimental examination has been carried out in AWGN(Additive White Gaussian Noise) and Rayleigh fading channel environment in order to prove validity of the proposed method.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.24 no.6A
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• pp.871-880
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• 1999

In this paper, a pseudo-noise(PN) tracking and demodulation circuits are analyzed and designed for a direct-sequence/spread-spectrum multiple access system under a mobile fading channel. We consider noncoherent delay locked loop(DLL) as a PN code tracking loop which has 1/8 PN chip resolution. The tracking performance of DLL is evaluated in terms of locking time from a loose state and tracking jitter. The received signal is demodulated to original data by despreading with PN code locked by DLL. Also the designed circuit supports sound service of 32Kbps and in-band signal with 4.096MHz chip clock. The circuits are implemented and verified with FPGA, which is shown completely data recovery under AWGN 7dB and will be available for IMT-2000.

• Journal of Advanced Marine Engineering and Technology
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• v.34 no.6
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• pp.922-934
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• 2010

To arrange artificial reefs for marine afforestation effectively, tidal currents were analyzed by numerical experiments, and particle tracking based on tidal currents was carried out to clarify the path of algae spores. The experiments were conducted by the Environmental Fluid Dynamics Code (EFDC), and water column was vertically divided into five layers. Tidal current patterns were showed to be affected by main currents outside of the study area, and two circle currents were observed during the analysis of residual currents. Particle tracking lasted 15 days at three installation places where artificial reefs for marine afforestation could be deployed. According to the results of the particle tracking experiment, particle movements at the No.1 and No. 3 stations were belt types along the coastal line. The No. 2 station documented an ellipse type movement 300~500m from coast line. These results suggest that artificial reefs for marine afforestation should be installed in the belt zones at of the No. 1 and No. 3 stations, and in the ellipse zone at the No. 2 station.

• Journal of Advanced Navigation Technology
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• v.15 no.4
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• pp.495-501
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• 2011

The characteristics of a discriminator estimating a tracking error in a signal tracking loop of a GPS receiver can be affected by the noise power, and the slope of the discriminator function is actually lowered as the noise power increases. In this paper, an algorithm to compensate the lowered slope of the function using the estimated C/N0 is studied, and a new design method of a code tracking which provides more accurate tracking error than a conventional one by adopting the compensation algorithm is proposed. Through the experimental results, finally, it has been check that the accuracy of the proposed DLL is enhanced about 50% when the dynamics of the vehicle is 20g/s.

• Proceedings of the IEEK Conference
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• 1998.06a
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• pp.277-280
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• 1998

The paper provides an overview of those requirements. A detailed description is given of the construction of the new channel code, called 24/25 code, that compiles with the given constraints and involves only a minor drawback in terms of the overhead needs. The servo position information is recorded as low frequency componets, pilot tracking tones, which are embedded in the recorded stream of binary digits. Pilot tracking Tones are used to derive head position reference information in camcorders and DVCRs. A simple pilot tone encoder has been designed by using a new approach, "2 path precoder". Owing to this method, the hardware size can be significantly reduced. the correctness of the method has been verified by theoretical analysis and by extensive simulation.imulation.