Precision thrust is critical for drag-free space gravity detection, yet micro-thrust measurement suffers from thermal drift. This study proposes a novel compensation method using time-varying-delay driven nonlinear mapping. We employ adaptive VMD, optimized by an improved PSO, for delay alignment, and a parallel TCN-Transformer model with a hybrid loss function to map temperature-drift relationships. Experiments demonstrate a 97.9% reduction in signal amplitude spectral density at 10⁻⁵ Hz (from 14.99 to 0.32 μN/Hz¹/²), effectively mitigating thermal drift in ultra-low-frequency systems under time-varying delay conditions.

Thermal drift compensation, improved PSO, VMD, TCN, Transformer.