High-Accuracy Multinode Ranging For Coherent Distributed Antenna Arrays

The design and experimental implementation of a waveform for high-accuracy internode ranging in a coherent distributed antenna array is presented. Based on a spectrally sparse high-accuracy ranging waveform, the presented multifrequency waveform enables high-accuracy ranging between multiple nodes in an array simultaneously, without interference. The waveform is based on a unique time-frequency duplexing approach combining a stepped-frequency waveform with different step cycles per node pair. The waveform also inherently includes beneficial disambiguation properties. The ambiguity function of the waveform is derived, and theoretical bounds on the ranging accuracy are obtained. Measurements were conducted in software-defined radio-based nodes in a three-element distributed array, demonstrating high-accuracy unambiguous ranging between two slave nodes and one master node.