Dr. Nir Regev is the founder and chief scientist of AlephZero. Senior research scientist, with over 24 years of experience in developing algorithms. Loves engineering problems that are unsolvable. Specializing in radar and lidar signal processing, computer vision, multi-target tracking, radar micro-Doppler, deep learning based target classification, optimization and statistical signal processing. Nir holds a Ph.D. in electrical engineering from the Ben-Gurion University of the Negev, Israel, with research focused on the problem of radar remote vital signs sensing, and the classification and recognition of radar targets.
The Micro-Doppler Effect in Radar: Next Generation Remote Medical Applications
In the last two and a half decades there has been an increasing body of work on the micro-
Doppler effect for various applications. Researchers used micro-Doppler signatures to
analyze, classify and detect human gait, hovering helicopters and wind-turbines, as well as jet
engine modulation (JEM) to detect jet aircrafts.
In recent years, the use of the micro-Doppler effect has expanded and taken also to the monitoring of
biological signals. Researchers started investigating the use of the effect to extract vital signs
such as breathing and heartbeat. The employment of various algorithms, such as the Chirp Z
Transform and Fourier analysis, has been advocated. Multiple radars have been investigated in
this context, from UWB and X-Band, to 24, 60, and 77GHz radar bands. The methods developed
suffer from insufficient spectral resolution, as Fourier analysis type algorithms need a large time-
window of data to support a certain resolution. Another caveat is the fact that the respiration
frequency is lower than the heart-beat, while its amplitude is much larger coupled with inherent
nonlinearities in the radar hardware, rendering the spectrum of the signal densely populated with
harmonics of both the respiration and heartbeat and their inter-modulations. This tutorial will
give an introduction to micro-Doppler with the derivation of the micro-Doppler effect of a
vibrating target with a live-demo of radar based vital signs extraction from afar.