Numerical and experimental studies of target detection with MIMO radar

摘要

Spatially diverse multiple-input multiple-output (MIMO) radar systems combine multistatic measurements of the target under view into a single detection algorithm and are thereby expected to alleviate the effects of fading on target radar cross sections (RCS) as the angle of observation is varied. Previous analytical studies of target detection for this case have shown that MIMO radar detection performance can exceed that of the corresponding phased array radar if both sufficient spatial diversity and signal-to-noise ratio (SNR) are achieved. These results have been based on a statistical model for the multistatic RCS of the target that is similar to the traditional Swerling models of the monostatic RCS. The degree to which these results are applicable to specific target geometries therefore remains uncertain. To address this issue, two studies of MIMO radar target detection incorporating realistic RCS properties for specific target geometries were performed. The first study utilized a numerical method to compute the multistatic RCS of a helicopter-like target observed at center frequency 200 MHz, while the second involved radar measurements of an unmanned aerial vehicle (UAV) target at 2.75 and 4.5 GHz. MIMO radar configurations having two transmitters and either three (for the radar measurements) or four (numerical simulations) receivers were used. In both cases, multistatic received fields were combined with regulated thermal noise levels in postprocessing to study target detection performance. Because in general the azimuthal orientation of a specific target with respect to the radar is uncertain, the detection performance results shown are averaged over the azimuthal orientation angle of the target. The average over target orientation can also be interpreted as similar to an average over ???trials??? of a statistical target description, enabling comparisons of field properties averaged over target orientation with similar ensemble averages from the statistical - odels of the literature. Although detection performance curves for the specific targets considered are not identical to those predicted analytically by the statistical target model, results for these targets confirm that the MIMO radar system can achieve enhanced detection performance as compared with the corresponding phased array radar system.