W-Band FMCW Radar for Range Finding, Static Clutter Suppression & Moving Target Characterization

Abstract

Many radar applications today require accurate, real-time, unambiguous measurement of target range and radial velocity. Obstacles that frequently prevent target detection are the presence of noise and backscatter from other objects, referred to as clutter. In this thesis, a method of static clutter suppression is proposed to increase detectability of moving targets in high clutter environments. An experimental dual-purpose, single-mode, monostatic FMCW radar, operating at 108 GHz, is used to map the range of stationary targets and determine range and velocity of moving targets. By transmitting a triangular waveform, which consists of alternating upchirps and downchirps, the received echo signals can be separated into two complementary data sets, an upchirp data set and a downchirp data set. In one data set, the return signals from moving targets are spectrally isolated (separated in frequency) from static clutter return signals. The static clutter signals in that first data set are then used to suppress the static clutter in the second data set, greatly improving detectability of moving targets. Once the moving target signals are recovered from each data set, they are then used to solve for target range and velocity simultaneously. The moving target of interest for tests performed was a reusable paintball (reball). Reball range and velocity were accurately measured at distances up to 5 meters and at speeds greater than 90 m/s (200 mph) with a deceleration of approximately 0.155 m/s/ms (meters per second per millisecond). Static clutter suppression of up to 25 dB was achieved, while moving target signals only suffered a loss of about 3 dB.