Adaptive Dithering for Improved Dynamic Range in Mixed-Resolution ADC Digital Radars

Abstract

Digital radars with low-resolution analog-to-digital converters (ADCs) can reduce digital processing complexity and power consumption but suffer from limited dynamic range. The poor dynamic range causes high radar cross-section (RCS) targets to mask low-RCS ones. To mitigate this issue, we propose operating the ADC at a high resolution during the initial slowtime slot of each radar frame. The high-resolution measurements are used to estimate the range and RCS of dominant targets, which, along with their known Doppler statistics, are used to construct a dither signal. This dither signal is then employed to acquire low-resolution ADC measurements in the subsequent slow-time slots. With the proposed receiver architecture, our method suppresses strong target returns in the low-resolution measurements, effectively unmasking weak targets. Simulations demonstrate significant improvements in target detection and reduced normalized mean square error in radar channel estimation compared to existing benchmarks.