A Microwave Sensor With Submillimeter Range Accuracy Using Spectrally Sparse Signals

Many modern and emerging applications; including sensor networks, Internet of Things (IoT), industrial process monitoring, and distributed phased arrays, among others; require high-accuracy localization. Achieving submillimeter accuracy requires wideband waveforms, typically linear frequency-modulated or spread-spectrum waveforms, which limits the use of low-cost commodity hardware such as software-defined radios, which have limited instantaneous bandwidths. In this letter, we demonstrate a novel approach to high-accuracy localization using spectrally sparse waveforms and a dual-channel microwave sensor. We use a dual-tone waveform with low-bandwidth pulse modulation, where each tone is generated and received by a separate transceiver on the two-channel sensor. The individual tones may be separated by any bandwidth up to the operational limitations of the system for increased localization accuracy, while using instantaneously narrowband signals on each channel. We demonstrate localization accuracy of 530 μm with tone separations of 450 MHz on a 2-GHz carrier frequency.