Multipath Identification and Mitigation with FDA-MIMO Radar

TL;DR

This paper introduces a novel FDA-MIMO radar-based method for identifying and suppressing multipath signals in urban environments, significantly improving target detection accuracy without prior knowledge of multipath components.

Contribution

The research transforms multipath suppression into a recognition problem, enabling separation of multipath components from single-frame data using spectral and angle analysis, and mitigates high-order multipath through joint array and frequency optimization.

Findings

Effective multipath identification in single and multi-target scenarios

Superior performance compared to general MIMO radar

Accurate separation of direct and multipath components

Abstract

In smart city development, the automatic detection of structures and vehicles within urban or suburban areas via array radar (airborne or vehicle platforms) becomes crucial. However, the inescapable multipath effect adversely affects the radar's capability to detect and track targets. Frequency Diversity Array (FDA)-MIMO radar offers innovative solutions in mitigating multipath due to its frequency flexibility and waveform diversity traits amongst array elements. Hence, utilizing FDA-MIMO radar, this research proposes a multipath discrimination and suppression strategy to augment target detection and suppress false alarms. The primary advancement is the transformation of conventional multipath suppression into a multipath recognition issue, thereby enabling multipath components from single-frame echo data to be separated without prior knowledge. By offsetting the distance steering vectors of different objects to be detected, the accurate spectral information corresponding to the current distance unit can be extracted during spatial spectrum estimation. The direct and multipath components are differentiated depending on whether the transmitting and receiving angles match. Additionally, to mitigate high-order multipath, the echo intensity of multipath components is reduced via joint optimization of array transmit weighting and frequency increment. The numerical results show that the proposed algorithm can identify multipath at different distances in both single-target and multi-target scenarios, which is superior to the general MIMO radar.