Long-Range Drone Detection of 24 G FMCW Radar with E-plane Sectoral Horn Array

In this work, a 24-GHz frequency-modulated continuous-wave (FMCW) radar system with two sectoral horn antennas and one transmitting lens antenna for long-range drone detection is presented. The present work demonstrates the detection of a quadcopter-type drone using the implemented radar system up to a distance of 1 km. Moreover, a 3D subspace-based algorithm is proposed for the joint range-azimuth-Doppler estimation of long-range drone detection. The effectiveness of the long-range drone detection is verified with the implemented radar system through a variety of experiments in outdoor environments. This is the first such demonstration for long-range drone detection with a 24-GHz FMCW radar. © 2018 by the authors. Licensee MDPI, Basel, Switzerland.1

Enterovirus 71-associated hand, foot and mouth diseases with neurologic symptoms, a university hospital experience in Korea, 2009

PurposeHand-foot-mouth disease (HFMD) is a common viral illness in children, which is usually mild and self-limiting. However, in recent epidemics of HFMD in Asia, enterovirus 71 (EV71) has been recognized as a causative agent with severe neurological symptoms with or without cardiopulmonary involvement. HFMD was epidemic in Korea in the spring of 2009. Severe cases with complications including death have been reported. The clinical characteristics in children with neurologic manifestations of EV71 were studied in Ewha Womans University Mokdong Hospital.MethodsExaminations for EV71 were performed from the stools, respiratory secretion or CSF of children who presented neurologic symptoms associated with HFMD by realtime PCR. Clinical and radiologic data of the patients were collected and analyzed.ResultsEV71 was isolated from the stool of 16 patients but not from respiratory secretion or CSF. Among the 16 patients, meningitis (n=10) was the most common manifestation, followed by Guillain-Barré syndrome (n=3), meningoencephalitis (n=2), poliomyelitis-like paralytic disease (n=1), and myoclonus (n=1). Gene analysis showed that most of them were caused by EV71 subgenotype C4a, which was prevalent in China in 2008.ConclusionBecause EV71 causes severe complications and death in children, a surveillance system to predict upcoming outbreaks should be established and maintained and adequate public health measures are needed to control disease

An Efficient TDOA-Based Localization Algorithm without Synchronization between Base Stations

An efficient localization algorithm is proposed by utilizing the time difference of arrival (TDOA) without synchronization between base stations. Generally, a TDOA-based localization algorithm requires synchronization between base stations in order to improve the accuracy of localization. Hence, correlations using wideband signals or wire connections between base stations have been used to synchronize the base stations; however, these approaches result in additional operating costs. Thus, the proposed algorithm does not require synchronization between base stations. The TDOA equations are derived by continuously varying the locations of the source and the location of a base station. The number of packets necessary for localization is also reduced. The localization performance of the proposed algorithm is verified with Monte-Carlo simulations

Packet-reduced ranging method with superresolution TOA estimation algorithm for chirp-based RTLS

In this paper, a packet-reduced ranging method using a superresolution time of arrival estimation algorithm for a chirp-based real-time locating system is presented. A variety of ranging methods, such as symmetric doublesided two-way ranging (SDS-TWR), have been proposed to remove the time drift due to the frequency offset using extra ranging packets. Our proposed method can perform robust ranging against the frequency offset using only two ranging packets while maintaining almost the same ranging accuracy as them. To verify the effectiveness of our proposed algorithm, the error performance of our proposed ranging method is analyzed and compared with others. The total ranging performance of TWR, SDSTWR, and our proposed TWR are analyzed and verified through simulations in additive white Gaussian noise and multipath channels in the presence of the frequency offset. ? 2013 ETRI.1

Robust self-cancellation-based time-of-arrival estimation algorithm to carrier frequency offset for bi-directional chirp signals

This study presents a robust self-cancellation-based time-of-arrival (TOA) estimation algorithm against carrier frequency offset (CFO). The proposed algorithm is developed to exploit the up and down chirp of bi-directional chirp signals. Using the relationship between the phase shifts of the transformed signals of the up and down chirp symbols, the CFO-induced error of the TOA estimates can be cancelled without pre-estimation and compensation through the proposed method. The root mean squared error of the proposed algorithm is analysed and verified through simulations in an additive white Gaussian noise and multi-path channel in the presence of CFO.FALS

Chirp Spread Spectrum Transceiver Design and Implementation for Real Time Locating System

A chirp spread spectrum (CSS) transceiver architecture for IEEE 802.15.4a is proposed and implemented. In the transmitter, the size of the read-only memory that stores CSS signal samples for the chirp modulator is reduced by removing duplicate samples among subchirps. In the receiver, a matched filter is utilized to remove the other band noise caused by the band hopping property of CSS. A robust time synchronizer and chirp demodulator based on the matched filter are proposed. Low complexity architectures of the matched filter and biorthogonal decoder are also proposed. All of the proposed architectures are implemented in the field-programmable gate array chip and verified

Dual Channel S-Band Frequency Modulated Continuous Wave Through-Wall Radar Imaging

This article deals with the development of a dual channel S-Band frequency-modulated continuous wave (FMCW) system for a through-the-wall imaging (TWRI) system. Most existing TWRI systems using FMCW were developed for synthetic aperture radar (SAR) which has many drawbacks such as the need for several antenna elements and movement of the system. Our implemented TWRI system comprises a transmitting antenna and two receiving antennas, resulting in a significant reduction of the number of antenna elements. Moreover, a proposed algorithm for range-angle-Doppler 3D estimation based on a 3D shift invariant structure is utilized in our implemented dual channel S-band FMCW TWRI system. Indoor and outdoor experiments were conducted to image the scene beyond a wall for water targets and person targets, respectively. The experimental results demonstrate that high-quality imaging can be achieved under both experimental scenarios