Analog Kalman Filter with Integration and Digitization via a Shared Thyristor-Based VCO for Sensor Fusion in 65 nm CMOS

This paper presents an analog Kalman filter employing a shared VCO scheme that takes sensor data from a gyroscope and an accelerometer as input and generates a digitized estimate of the attitude via sensor fusion. The VCO-based integrator and ADC are designed to consume minimal power and implementation overhead by sharing a CMOS thyristor-based VCO operating in the subthreshold region. The silicon prototype is fabricated in 65 nm technology and achieves 0.8° RMSE using real sensor data, and the embedded ADC measures 51.58 dB SNDR and 57.28 dB SFDR under a single-tone test.