Automatic Measurement of Blade Length and Rotation Rate of Drone Using W-Band Micro-Doppler Radar

For the classification of target, one should utilize different features of target that others do not have. In case of drone as a target, classification requires input parameters, such as a number of blades, blade length, frame size, and rotations per second (RPS). In this paper, we have introduced an algorithm for automatic calculation of blade length and RPS using micro-Doppler signature. We used time-frequency domain for the analysis of received signal and the variation in micro-Doppler frequency with time gives relationship with blade length and RPS. For experimental purpose, W-band homodyne micro-Doppler radar is developed using designed low-loss high-gain modules of transmitter, low noise front-end, and downconverter. The transmitter output power is 25 dBm, front-end gain is 51 dB over 4 GHz bandwidth, and conversion loss of downconverter is -12 dB. Validation of the proposed algorithm has been done by analyzing experimental data for single rotor, double rotors, and quad rotors cases, and measurement results achieve average error of 1.3% (with maximum 6.1% error) in estimation of blade length using W-band Doppler radar.