Online Incremental Non-Gaussian Inference for SLAM Using Normalizing Flows

This paper presents a novel non-Gaussian inference algorithm, Normalizing Flow iSAM (NF-iSAM), for solving SLAM problems with non-Gaussian factors and/or nonlinear measurement models. NF-iSAM exploits the expressive power of neural networks to model normalizing flows that can accurately approximate the joint posterior of highly nonlinear and non-Gaussian factor graphs. By leveraging the Bayes tree, NF-iSAM is able to exploit the sparsity structure of SLAM, thus enabling efficient incremental updates similar to iSAM2, although in the more challenging non-Gaussian setting. We demonstrate the performance of NF-iSAM and compare it against state-of-the-art algorithms such as iSAM2 (Gaussian) and mm-iSAM (non-Gaussian) in synthetic and real range-only SLAM datasets with data association ambiguity.