Signal Processing and Speech Communication Laboratory
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Single-Anchor, Multipath-Assisted Indoor Positioning with Aliased Antenna Arrays

Fri, Mar 01, 2019

Highly accurate indoor positioning is still a hard problem due to interference caused by multipath propagation and the resulting high complexity of the infrastructure. We focus on the possibility of exploiting information contained in specular multipath components (SMCs) to increase the positioning accuracy of the system and to reduce the required infrastructure, using a-priori information in form of a floor plan. The system utilizes a single anchor equipped with array antennas and wideband signals to allow separating the SMCs. We derive a closed form of the Cramér-Rao lower bound for array-based multipath-assisted positioning and examine the beneficial effect of spatial aliasing of antenna arrays on the achievable angular resolution and as a direct consequence onto the positioning accuracy. It is shown that ambiguities that arise due to the aliasing can be resolved by exploiting the information contained in SMCs. The theoretic results are validated by simulations.

The figure illustrates the position error bound (PEB) for three different array geometries, comparing standard uniform linear arrays (ULAs) with 2 elements (AI) and 11 elements (AIII) spaced at λ/2 and a ULA with 2 elements spaced at 5λ. The three subplots visualize the contribution of angle estimation (top), range estimation (middle) to the overall PEB (bottom). The aliased array (AII) achieves a much higher angulation accuracy (top) compared to the standard ULA (AI) while showing identical ranging performance (middle). The bottom plot shows that for small anchor to agent distances, the aliased array (AII) can achieve a similar positioning accuracy as a the hardware intensive 11-element array (AIII). 

More information can be found in our paper.

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