Optimized Radar Waveform Parameter Design for Small Drone Detection Based on Echo Modeling and Experimental Analysis

Abstract

Monitoring small drones is significant for security requirements, but it is challenging because of small drones' low radar cross section (RCS) and hovering ability. In order to analyze the effect of radar waveform on the echo spectra and optimize the waveform design, an analytical expression of the rotor's temporal RCS is desired. Integral model, a widely used radar echo model of the rotor's temporal RCS, does not involve the electromagnetic scattering, thus it cannot be applied to all frequency bands. The method of moments (MoM) is a strictly numerical method based on the Maxwell's equations, but cannot obtain the analytical expression. Hence, this paper proposes a new method combing the integral model and MoM to model the rotor's temporal RCS in very high frequency (VHF) band. The linear frequency modulation (LFM) signal which has a high Doppler tolerance and a large gain bandwidth product is adopted in optimizing waveform parameters design. Based on the new method, the analytical expression of LFM echo is also derived. Moreover, the spectral spread over range and Doppler dimension caused by the rotating rotors is analyzed in detail. A criterion for optimizing the LFM waveform parameters for small drone detection is presented. Field experiments confirm the validity of the echo model and waveform parameters optimization criterion, and the full Acrylonitrile Butadiene Styrene small drone is successfully detected in VHF band. In addition, experiments are implemented to verify the applicability of the echo model and waveform parameters optimization method to other drones with different size.INDEX TERMS Small drone detection, electromagnetic scattering, method of moments (MoM), numerical simulation, linear frequency modulation (LFM) signal.

A Novel PE/FDTD Hybrid Model for Predicting Echo Signals of Radar Targets in Large-Scale Complex Environments

“…x reflects the diffraction effect of obstacles on the radio wave propagation path. After the initial field is provided, the field value of the whole calculation area can be calculated step-by-step by (2). In this paper, the parabolic equation model refers to the literature [23] for the treatment of rain and fog environment, the literature [24] for the treatment of terrain, and the literature [25] for the treatment of atmospheric duct environment.…”

“…To sum up, using PE/FDTD model to calculate the echo of the target can be divided into the following steps: 1) First, the target scattering field is calculated by FDTD, and then the target far-field characteristic function H Far (f ) is calculated by equation (10)-(13). 2) Second, the step-by-step iterative calculation of the field in the calculation region is carried out by formula (2). Calculate the field value u(R tar ) at the target location.…”

“…Radar target echo signal prediction is widely used in ocean detection [1], target recognition [2], SAR imaging [3], long-range radar surveillance [4], missile fuze [5] and other fields. In order to obtain accurate radar target echo signal, many kinds of researches on echo measurement and model have been carried out [6], [7].…”

Integral equation modelling of unmanned aerial vehicle radar scattering characteristics in VHF to S frequency bands

“…Research and development associated with UAVs have two sides. On the one hand, drone developers strive to reduce the EM signatures of UAVs, and on the other hand, radar and signal processing engineers work to improve the efficiency of UAV radar detection and tracking [1][2][3][4][5][6][7][8][9][10][11][12]. In both cases, methods of physical [2][3][4][5][6][7][8][9][10][11] and mathematical [2-4, 8, 10, 13] modelling are applied to obtain UAV radar scattering characteristics.…”

“…On the one hand, drone developers strive to reduce the EM signatures of UAVs, and on the other hand, radar and signal processing engineers work to improve the efficiency of UAV radar detection and tracking [1][2][3][4][5][6][7][8][9][10][11][12]. In both cases, methods of physical [2][3][4][5][6][7][8][9][10][11] and mathematical [2-4, 8, 10, 13] modelling are applied to obtain UAV radar scattering characteristics. Mathematical methods allow, without significant expenditures of materials and time, the simulation of EM wave scattering from UAVs of various shapes and materials and for various radar-probing scenarios.…”