Cheonsig Sin

Robust Cross-SCORE Algorithm Against Bit Transitions for GPS Interference Suppression

In the blind beamforming technique utilizing self-coherence properties of GPS signals, the covariance matrices estimated from sample data, including the transition between two adjacent bits, suffer from performance degradation. In this letter, we propose the estimation of the covariance matrices using the sample blocks, which are free from the bit transitions under different times of arrival of multiple GPS signals. It combines with the robust cross-SCORE algorithm to suppress the GPS interference. It is shown that an efficient combination of two algorithms is capable of providing high gains to multiple GPS signals simultaneously, while suppressing strong interference.

Pascal's triangle-based range-free localization for anisotropic wireless networks

This paper introduces a Pascal’s triangle model to draw the potential locations and their probabilities for a normal node given the hop counts to the anchors according to the extent of detour of the shortest paths. Based on our proposed model, a Pascal’s triangle-based localization (PTL) algorithm using local connectivity information is presented for anisotropic wireless networks with a small number of anchors. The superiority of the PTL algorithm has been validated over the state-of-the-art algorithms through MATLAB simulations. We have shown that compared to the other algorithms, the PTL algorithm achieves higher localization accuracy with even fewer anchors. We have also validated the performance of the PTL algorithm in a real environment.

Integrated PDR/fingerprinting indoor location tracking with outdated radio map

This paper presents an indoor location tracking algorithm that integrates pedestrian dead reckoning (PDR) positioning and fingerprinting positioning. The Kalman filter is applied for the integration of two different positioning approaches. In practice, received signal strength (RSS) significantly varies by not only environmental changes, but also device types and device orientations. Due to the RSS variation problem, the radio map constructed in the offline phase of the fingerprinting positioning becomes outdated or inaccurate. The outdated radio map leads to unreliable fingerprinting positioning results, and the errors are contained in the tracking results. A RSS transformation method is proposed which scales the online RSS according to the difference from the offline RSS to obtain more reliable fingerprinting positioning results with the outdated radio map. The proposed algorithm is implemented into an Android-based smartphone and evaluated in a real environment. Through the experimental results, it is shown that the proposed algorithm enables higher accuracy than the Kalman filter-based location tracking algorithm without the RSS transformation.

Analysis of 3D GIS- Based GNSS Visibility at Urban Area

Visibility of the satellite navigation is related to a environmental condition of a receiver. Obstacles like buildings and trees in urban areas can block signals and have effects on accuracy and reliability of positioning. This paper presents a method of creating 3D analysis model of urban canyon of Seoul using three-Dimensional digital map. Analysis techniques of visible satellites with Ray-Polygon Collision Detection and validation of algorithm through field tests are discussed. We have compared and analyzed the visibility of GPS and Galileo with respect to separate and simultaneous tracking in view of DOP (Dilution of Precision) using the 3D GIS digital map.

Design of GNSS jamming propagation simulator using ITU-R P.1546 propagation model

As Location Based Services(LBS) are developing rapidly in the mobile and information technologies, Global Navigation Satellite System (GNSS) including GPS also becomes very important. But, there is critical problem that GNSS signal is very weak and easily damaged by the jamming attack. The GNSS jamming can cause the social confusion by making the GNSS receiver broke down or malfunctioned. The prediction and analysis of the jamming propagation should be needed to prevent and cope with the damage of the jamming. So, we are developing GNSS interference verification platform which simulates a jamming environment and provides the effect by the jamming propagation. In this paper, we present the design of GNSS jamming propagation simulator based on ITU-R P.1546 propagation prediction model. This simulator will provide the analysis of the jamming propagation based on the geographical information and the damage status of the GNSS receiver by the jamming effect in Korea territory.

A Sequential Approach to Direct Multi-Target Localization in MIMO Radar Networks

ABSTRACTThis paper presents a direct multi-target localization algorithm for multiple-input multiple-output radar networks employing code division multiple access signals. The proposed algorithm lo...

Kalman-based mobility tracking with range-free localization under a realistic device distribution

The performance of range-free localization is vulnerable to change of connectivity information. To solve the problem, we propose a Kalman-based mobility tracking algorithm combined with range-free localization under a realistic device distribution. We considered a large indoor environment of a real shopping mall for the performance evaluation. To simulate the real propagation scenario, the radio irregularity was applied on the map of the shopping mall according to the location of devices. We demonstrate that the Kalman-based mobility tracking with range-free measurements outperforms the range-free only localization algorithm. Various factors such as the device distribution density, radio irregularity, and communication range influencing the tracking performance was analyzed.

GNSS jamming propagation prediction simulator based on ITU-R P.1546 model

The reliability of Global Navigation Satellite System (GNSS) has been very important according to an ever-increasing dependency on GNSS in the position, navigation, and timing (PNT) applications. Nevertheless, there is still a distinctive weakness that GNSS signal is easily damaged by the jamming attack. GNSS jamming incident is considered to be an act of provocation that poses a threat to the security of the country and undermines the safety of civil transportation, including aircraft and vessels. Particularly, GNSS jamming can cause serious damage in the safety-critical applications like the civil aircraft or self-driving smart cars. In this paper, we present the GNSS jamming propagation prediction simulator based on ITU-R P.1546 model for estimating the damage of the GNSS jamming. This simulator predicts the jamming propagation strength based on the geographical information of Korean peninsula. The prediction results of our simulator are verified through comparison with those from the Longley-Rice model.

A hyperbolic distance measurement model for range-free localization in anisotropic networks

This paper presents a hyperbolic distance measurement model where the difference between the distances from a normal node to two anchors is defined as the sum of the difference between the distances from another anchor to the anchors and an error. A hyperbolic range-free localization algorithm is then introduced based on the proposed model for anisotropic networks. The proposed algorithm estimates the location of each normal node by selecting hyperbolic distance measurements with maximum errors less than a predefined threshold. Simulation results show the superiority of the proposed algorithm over existing range-free localization algorithms.

Advanced Fine-Acquisition Scheme for E5a Signal on Galileo Giove-B

This paper proposes the advanced fine-acquisition scheme using the E5a signal transmitted from the Galileo GIOVE-B satellite. The proposed approach is based on the code phase changes which occur during the acquisition processing time originating in the Doppler frequency. The proposed scheme detects a fast code phase within about 1 chip near the estimated code phase and improves the accuracy of the Doppler frequency in comparison with the conventional scheme. The feasibility of the proposed schemes is demonstrated through simulation