Review of radar classification and RCS characterisation techniques for small UAVs or drones

Abstract

This review explores radar based techniques currently utilised in literature to monitor small UAVs or drones; several challenges have arisen due to their rapid emergence and commercialisation within the mass market. The potential security threats posed by these systems are collectively presented and the legal issues surrounding their successful integration is briefly outlined. Key difficulties involved in the identification and hence tracking of these 'radar elusive' systems are discussed, along with how research efforts relating to drone detection, classification and RCS characterisation are being directed in order to address this emerging challenge. Such methods are thoroughly analysed and critiqued; finally, an overall picture of the field in its current state is painted, alongside scope for future work over a broad spectrum.

Classification of drones and birds using convolutional neural networks applied to radar micro‐Doppler spectrogram images

“…Hence, a radar sensor is a primary candidate for any drone detection and classification system. In the last few years, there has a been a proliferation of publications concerning the classification of drones using radar [2].…”

An Investigation of Rotary Drone HERM Line Spectrum under Manoeuvering Conditions

“…The classification of drones via radar signatures using micro-Doppler information has been investigated using a variety of techniques [ 5 , 6 ]. Some approaches include using features derived from spectrograms [ 7 ], the application of deep learning techniques to range-Doppler maps [ 8 ], and cadence–velocity diagrams [ 9 ], as well as polarimetry [ 10 ].…”

“…Micro-Doppler radar signatures are studied using time-frequency analysis, and most commonly using the Short Time Fourier Transform (STFT) [ 2 , 3 , 5 , 6 , 11 , 12 , 13 , 14 , 15 ]. Depending on the STFT window length, two different types of spectrograms are obtained.…”

Measurements of Multistatic X&L Band Radar Signatures of UAVS

“…These targets are smaller (hence reduced Radar Cross Section) and more manoeuvrable than their manned counterparts or larger Unmanned Aerial Vehicles (UAVs), meaning that they can get lost in the detection of tracking process. Increasing the sensitivity of the radar would help, but the related challenge would be the significant number of false targets due to mostly birds and moving non-drone objects (vegetation, wind turbines) [1][2].…”