Multiband TDOA estimation from sub-Nyquist samples with distributed wideband sensing nodes

In this work, we estimate relative autocorrelation functions of multiple unknown transmissions that occupy distinct narrowband frequency bands from their sub-Nyquist samples. To be able to do so, we employ a network of distributed sensing nodes that are equipped with a sub-Nyquist receiver system and have access to a common clock. Utilizing low-rate out-puts of different nodes, we recover the central frequencies and the relative autocorrelation functions of individual transmissions within the wideband input, where the latter can then be used to determine corresponding time differences of arrival (TDoAs). We propose two recovery approaches; we either recover the central frequencies and the relative autocorrelations jointly or adopt a two-step procedure where the two are estimated independently. Our numerical results confirm the applicability of the proposed methods for relative multiband autocorrelation estimation from sub-Nyquist samples.