A Thermal Convection Tilt Sensor With Synergistic Thermal Control and Adaptive Filtering for Long-Term Drift Suppression

Abstract

This paper presents a thermal convection tilt sensor with synergistic thermal control and adaptive filtering for long-term drift suppression. Experimental investigations reveal that the baseline drift of the sensor primarily originates from the instability of the internally generated thermal convection field. To address this limitation, a closed-loop temperature control (CTC) circuit is developed to actively regulate the microheater through continuous negative feedback, stabilizing the thermal excitation source and reducing the temperature-induced drift by approximately 90%. Based on this source-level stabilization, a three-mode adaptive fusion filter is proposed to further suppress residual ultra-low-frequency baseline wander and high-frequency noise, achieving an additional 70% reduction in fluctuation amplitude while preserving the dynamic step response. Together, the two complementary mechanisms establish a unified stabilization framework across both physical and signal domains, which achieves a minimum detectable angle (MDA) of 0.0698° and an output standard deviation of 0.601 mV. Allan deviation analysis further confirms the substantial improvements in long-term stability, with the acceleration random walk (ARW) reduced to $2.399\times 10 ^{-7\circ }$ / $\surd $ Hz and the bias instability (BI) reduced to $5.317\times 10 ^{\mathrm {-9}\circ }$ . These results demonstrate that the proposed dual-stage stabilization framework provides an effective solution for achieving highly stable thermal convection tilt sensing in precision measurement applications.[2026-0102]