A Novel Approach for Multiple Moving Target Localization Using Dual-Frequency Radars and Time-Frequency Distributions

Accurate range estimation and tracking of moving targets is an important task in urban sensing applications. A dual-frequency radar, which estimates the range of a target based on the phase difference between two closely spaced frequencies, has been shown to be a cost-effective approach to accomplish both range-to-motion estimation and tracking. This approach, however, suffers from two drawbacks: it cannot deal with multiple moving targets, and has poor performance in noisy environments. To overcome these drawbacks, we propose, in this paper, the use of time-frequency signal representations. High signal-to-noise ratio (SNR) is obtained by focusing on the moving target instantaneous Doppler frequency law provided by the power localization properties of time-frequency distributions. The case of multiple moving targets is handled by separating the different Doppler signatures prior to phase estimation.