Search

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. [ABSTRACT FROM AUTHOR]

We proposed a dual smoothing superresolution direction-of-arrival (DOA) estimation for multitarget detection with two-channel frequency modulated continuous-wave (FMCW) radar. For the conventional superresolution FMCW radar, the number of detectable targets for DOA estimation is limited by the number of RX antenna arrays. To enable DOA estimation for more targets than the number of receiving channels, we propose exploiting a dual shift invariant structure of dual smoothed matrix. We implemented two-channel FMCW radar and tested the performance of the proposed method. [ABSTRACT FROM PUBLISHER]

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. [ABSTRACT FROM AUTHOR]

The demand for detecting and tracking drones has increased for reasons of surveillance and security. Radar is one of the promising methods in this regard. The recognition and identification of drones using a radar system requires the extraction of their unique micro‐Doppler signatures produced by their rotating blades. Because of the blades' rapid rotation speed, difficulties are inherent in visualizing clear micro‐Doppler signatures in a conventional joint time‐frequency analysis such as the short‐time Fourier transform. In this paper, we propose the use of high‐resolution transform techniques to visualize the micro‐Doppler signatures of drones in a spectrogram. The techniques used include Wigner‐Ville distribution, smoothed pseudo‐Wigner‐Ville distribution, and short‐time MUltiple SIgnal Classification (MUSIC) algorithm. In particular, the latter, which had never previously been applied to drones, is suggested to visualize the details of micro‐Doppler signatures. We measured three drones using a continuous‐wave radar, and performances of these algorithms were compared using data collected from the drones. We could observe that the short‐time MUSIC method showed the clearest spectrogram for identifying micro‐Doppler signatures. This study can potentially be useful in the field of drone classification. [ABSTRACT FROM AUTHOR]

In this paper, a modified 3D multiple signal classification (MUSIC) algorithm is proposed for joint estimation of range, azimuth, and elevation angles of K-band radar with a small 2 × 2 horn antenna array. Three channels of the 2 × 2 horn antenna array are utilized as receiving channels, and the other one is a transmitting antenna. The proposed modified 3D MUSIC is designed to make use of a stacked autocorrelation matrix, whose element matrices are related to each other in the spatial domain. An augmented 2D steering vector based on the stacked autocorrelation matrix is proposed for the modified 3D MUSIC, instead of the conventional 3D steering vector. The effectiveness of the proposed modified 3D MUSIC is verified through implementation with a K-band frequency-modulated continuous-wave (FMCW) radar with the 2 × 2 horn antenna array through a variety of experiments in a chamber. [ABSTRACT FROM AUTHOR]