Towards a Fast and Hardware Efficient Sub-MM Precision Ranging System

A sub-mm ranging system, which estimates the time of flight of a RF signal between two nodes using Time of Arrival (ToA) estimation, is possible according to maximum likelihood estimator simulations and theoretical bounds on ToA estimation. In this paper we propose a frequency domain based ToA estimator for an indoor ranging system which is broken into 3 computational steps towards an efficiently implementable estimator. Performance of this hardware efficient estimator is comparable with the maximum likelihood estimator´s and it is computationally efficient. Complexity of the computational steps can be traded off against each other. Moreover, the implementation-aware estimator provides high flexibility on choosing between transmitted signal energy, computational cost and precision of the ranging algorithm. In this work, a simulation precision better than 1 mm is obtained for SNRs below 0 dB, by transmitting an OFDM (Orthogonal Frequency Division Multiplexing) like signal whose duration is 9 μs, with a 6 GHz bandwidth on a 60 GHz carrier.