Spatially Resolved Fast-Time Vibrometry Using Ultrawideband FMCW Radar Systems

Abstract

Highly accurate vibrometry and ranging are important topics in the industrialized economy. Wherever optical measurement technology fails due to its high prices and vulnerability within harsh environments, millimeter-wave (mmWave) radar technology is well suited. This article introduces a signal processing chain for ultrawideband frequency-modulated continuous-wave (FMCW) radar. It uses fast-time measurement to evaluate the instantaneous phase, thus allowing for spatially resolved sensing of multiple simultaneously vibrating radar targets, faster than the chirp rate. In order to accomplish this, a sophisticated error model and a calibration scheme were derived. We used three FMCW radar systems covering a broad range of the mmWave spectrum to demonstrate the signal processing approach. In contrast to the commonly used slow-time measurement principle, the highest detectable frequency was improved from 55 Hz to at least 16 kHz, which is the upper limit of the audio range. Up to 10 kHz could be measured with an underlying large-scale motion of 0.4 m/s, while the vibration displacement was at a minimum of 30 nm.

A remaining useful life estimation method for solenoid valve based on mmWave radar and auxiliary particle filter technique

“…In addition, since a single sensor can only detect one device, the detection efficiency is low. But the millimeter-wave radar has high-sensitivity detection capabilities and can achieve high-precision non-destructive detection that undergoes small deformations or high-speed displacements [23,24,25,26,27,28]. These studies show that the use of millimeter-wave radars to detect the SV core displacement is reliable.…”

An mmWave Sensor for Real-Time Monitoring of Gases Based on Real Refractive Index

“…As the measurement principle relies on fast, highly precise, and stable measurements of the velocity of electromagnetic waves propagating through the gas under test, we used the following FMCW radar system as a signal source. The system introduced in [31]- [33] operates at a center frequency of 82 GHz with a bandwidth of 20 GHz. It has a sweep time of 1 ms, an analog-to-digital converter (ADC) sampling rate of 1 MHz, a sweep rate of 500 Hz, and output power of −4 dBm.…”

“…neglecting a residual phase due to a steep ramp slopeω = BT −1 , as discussed in [32] and [33]. The parameters ω 0 and B are the center frequency and bandwidth of the radar system in radians per seconds, and the "±"-sign belongs to upchirps and downchirps, respectively.…”

“…By using Wiener filters, the peaks were gained by 7 and 9 dB, respectively. (ROI), the bin interpolation is [32] and [33]…”

“…11 illustrates the procedure for estimation of the refractivity N from the signal parameters. The measurement 6 Rectangular: p = 0.78; Von-Hann: p = 0.23 [33]. 7 Phase unwrapping is the reconstruction of a sequence of phase values from their modulo 2π values.…”