A Hybrid Dual-Band Ultrasound Imaging SoC With Enhanced Spatial Resolution for UAV Applications

Unmanned Aerial Vehicle (UAV)/drone vision and navigation require low-power 3D depth-sensing with robustness against strong/weak light and various weather conditions. CMOS image sensor (CIS) and light detection and ranging (LiDAR) can provide high-fidelity imaging. However, CIS lacks depth sensing and has difficulty in low light conditions. LiDAR suffers from heavy fog and is costly. Radar is resilient in poor weather but tends to be bulky and expensive. Ultrasound imaging system (UIS), on the other hand, is robust in various weather and light conditions and is cost-effective; however, it usually has low imaging resolution and low frame rate. Using a higher frequency ultrasound theoretically enables higher resolution, yet this comes at the cost of short range due to greater attenuation and severe grating lobe phenomenon. Compared to prior air-channeled ultrasound imaging systems, this work is first to integrate low-frequency (LF) and high-frequency (HF) dual band ultrasound imaging into SoC, achieving highest angular resolution so far with near-zero frequency switching latency and typical 11.04M focal point/s throughput to enable real-time high resolution 3D imaging. System level validation including signal-to-noise ratio (SNR) VS range characterization, hybrid LF–HF imaging, two-point separation demonstrating 0.5° angular resolution, and in-air measurements on a flying drone confirms reliable operation at a 7 m range and 21 frames per second (fps) for both LF and HF modes. These results establish the hybrid dual-band SoC as an effective and practical 3D depth-sensing solution for UAV navigation under challenging environmental conditions. The SoC is implemented in 180 nm 1P6M Standard CMOS, occupies 30mm${}^{\mathbf {2}}$and consumes 116.1 mW.