Joint Time-Frequency Analysis and Multipath Exploitation for Monostatic Radar Multi-Object Localization

Multipath exploitation radar (MER) integrates the prior environment to make use of the extra target information encoded in multipath signals, which is capable of localization for single target with a wide-beam antenna. Nevertheless, as the number of targets in the urban scene increases, the association between the target and its corresponding multipath's time-of-arrival (ToA) faces the problem of combination explosion. Moreover, accounting for the measurement and extraction error attached with the ToAs, there may be multiple combinations with similar probability, which leads to a significant accuracy decline or even wrong location results. To solve the problem, this paper proposes a novel algorithm that jointly uses MER and time-frequency (TF) features for multi-target localization especially for pedestrians. Through the TF analysis of the micro-Doppler feature, the pedestrian characteristics such as pace and phase of periodic action can be obtained. Based on these characteristics, the multipath's ToAs in multi-target scenario can be associated with each different target, hence the aforementioned multi-target location problem can be transferred to a series of single-target localization problems. The impacts of target number on localization accuracy are analyzed in detail. The effectiveness of the proposed method is validated through the simulation experiments. The results indicate that, compared with the traditional methods, the proposed method has higher localization accuracy in multi-target scene.