LTE-based passive multistatic radar for high-speed railway network surveillance: design and preliminary results

2019 ◽  
Vol 11 (5-6) ◽  
pp. 482-489
Author(s):  
Rodrigo Blázquez-García ◽  
Jorge Casamayón-Antón ◽  
Mateo Burgos-García

AbstractWith the aim of performing perimeter surveillance of high-speed railway networks, this paper presents the design of a passive multistatic radar system based on the use of Long-Term Evolution (LTE) downlink signals as the illumination of opportunity. Taking into account the specifications and standard of the LTE system, the ambiguity function of measured downlink signals is analyzed in terms of range and Doppler resolution, ambiguities, and sidelobe level. The deployment of the proposed passive radar is flexible and scalable, and it is based on multichannel software defined radio receivers that obtain the reference and surveillance signals by means of digital beamforming. The signal processing and data fusion are based, respectively, on the delay-Doppler cross-correlation with the reconstructed reference signals and a two-stage tracking at sensor and central level. Finally, the performance of the proposed system is estimated in terms of its maximum detection range and simulation results of the detection of moving targets are presented, demonstrating its technical feasibility for the short-range detection of pedestrians, vehicles, and small drones.

ICTE 2015 ◽  
2015 ◽  
Author(s):  
Qiangfeng Zhang ◽  
Haifeng Yan ◽  
Shaoquan Ni ◽  
Wenting Zhang

2021 ◽  
Vol 2021 ◽  
pp. 1-16
Author(s):  
Qin Zhang ◽  
Xiaoning Zhu ◽  
Li Wang ◽  
Shuai Wang

The optimization problems of train timetabling and platforming are two crucial problems in high-speed railway operation; these problems are typically considered sequentially and independently. With the construction of high-speed railways, an increasing number of interactions between trains on multiple lines have led to resource assignment difficulties at hub stations. To coordinate station resources for multiline train timetables, this study fully considered the resources of track segments, station throat areas, and platforms to design a three-part space-time (TPST) framework from a mesoscopic perspective to generate a train timetable and station track assignment simultaneously. A 0-1 integer programming model is proposed, whose objective is to minimize the total weighted train running costs. The construction of a set of incompatible vertexes and links facilitates the expression of difficult constraints. Finally, example results verify the validity and practicability of our proposed method, which can generate conflict-free train timetables with a station track allocation plan for multiple railway lines at the same time.


2020 ◽  
Vol 35 (11) ◽  
pp. 1785-1799 ◽  
Author(s):  
Na Zhang ◽  
Xiaopeng Deng ◽  
Bon-Gang Hwang ◽  
Yanliang Niu

Purpose Balancing interfirm relationships is important for firms’ long-term superior performance. However, prior studies mainly focus on interfirm competition or interfirm cooperation separately, ignoring the balance of interfirm relationships. To bridge this gap in knowledge, this study aims to develop a framework to evaluate the balance of interfirm competition and interfirm cooperation and propose strategies to optimize a firm’s interfirm relationships. Design/methodology/approach After an in-depth literature review, a framework was developed for evaluating and optimizing the interfirm relationships. Taking the high-speed railway industry as an example, the proposed framework was implemented. Findings The results of the case confirm that the balancing of interfirm relationships can lead to more superior firm performance. Also, rather than mutual suppression, the interfirm competition and interfirm cooperation present a roughly positive relationship. Originality/value This study would contribute to the existing knowledge body by developing a framework for balancing interfirm relationships. Also, this study can aid practitioners in evaluating and optimizing their interfirm relationship structures.


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