Fast algorithm for 3D wideband LFM source localisation based on time delay under a uniform circular array

Traditional localisation technologies for wideband linear frequency modulation (LFM) source are always confined to the far-field situation and suffer from high computational cost for dealing with multiple sub-narrowband components. In this study, by performing temporal delay-and-correlation to wideband LFM signals, a fast and closed-form algorithm based on phase differences is proposed for three-dimensional (3D) source localisation (azimuth angle, elevation angle, and range) under a uniform circular array. First, the cross-correlation of the array outputs with their temporally delayed version is calculated to develop a new single-frequency signal model. Then, the phase differences of adjacent sensors’ transformed outputs are exploited to construct indefinite equations. After that, the least-square method is employed to estimate the source's 3D parameters simultaneously. Moreover, theoretical analysis and numerical examples show the aperture restriction in avoiding ambiguity can be relaxed under the new signal model. Finally, simulations demonstrate the effectiveness and advantages of the proposed algorithm.