Nonlinear filtering based on density approximation and deep BSDE prediction
Preprint, 2025

A novel approximate Bayesian filter based on backward stochastic differential equations is introduced. It uses a nonlinear Feynman–Kac representation of the filtering problem and the approximation of an unnormalized filtering density using the well-known deep BSDE method and neural networks. The method is trained offline, which means that it can be applied online with new observations. A hybrid a priori-a posteriori error bound is proved under a parabolic Hörmander condition. The theoretical convergence rate is confirmed in two numerical examples.

convergence order

Hörmander's condition

Fokker--Planck equation

deep learning

Filtering problem

backward stochastic differential equations

numerical analysis

Author

Kasper Bågmark

Chalmers, Mathematical Sciences, Applied Mathematics and Statistics

University of Gothenburg

Adam Andersson

University of Gothenburg

Chalmers, Mathematical Sciences, Applied Mathematics and Statistics

Stig Larsson

Chalmers, Mathematical Sciences, Applied Mathematics and Statistics

University of Gothenburg

Subject Categories (SSIF 2025)

Probability Theory and Statistics

Computational Mathematics

Mathematical Analysis

Roots

Basic sciences

Infrastructure

Chalmers e-Commons (incl. C3SE, 2020-)

DOI

10.48550/arXiv.2508.10630

More information

Latest update

4/23/2026