Core Concepts
By conditioning on an additional event that stipulates an inequality constraint between the real and virtual states, the standard conditional probabilities in Bayesian filtering can be transformed into convolutional forms. This generalized framework allows for explicit consideration of model mismatch, leading to more robust state estimation algorithms.
Abstract
The content discusses a new framework called "convolutional Bayesian filtering" that extends the standard Bayesian filtering approach to handle model mismatch. The key insights are:
Convolutional conditional probability: By adding an inequality condition between the real and virtual states/measurements, the standard conditional probabilities can be transformed into a convolutional form. This relaxes the need for complete information about the conditional probabilities.
Uncertain hidden Markov model: The real system is modeled as an "uncertain hidden Markov model" that distinguishes between the real and virtual states/measurements, and bounds their differences using the inequality conditions.
Convolutional Bayesian filtering: By substituting the standard total probability rule and Bayes' law with their convolutional counterparts, a generalized filtering framework is established that can explicitly account for model mismatch.
Analytical solution for Gaussian case: When the distance metrics are quadratic forms and the threshold distributions are exponential, an analytical form of convolutional Bayesian filtering can be derived, leading to a robust Kalman filter.
Exponential density rescaling: For non-Gaussian systems, an approximation technique based on exponential density rescaling is proposed, which relates to the information bottleneck theory.
The new framework encompasses standard Bayesian filtering as a special case, and allows for more nuanced handling of model uncertainties, leading to improved state estimation performance.