Numerical schemes of Markov jump process filtering given discretized observations II: Additive noise case

The note is a sequel of investigations initialized in the article Borisov, A. 2019. Numerical schemes of Markov jump process filtering given discretized observations I: Accuracy characteristics. Inform. Appl. 13(4):68–75. The basis is the accuracy characteristics of the approximated solution of the filtering problem for the state of homogeneous Markov jump processes given the continuous indirect noisy observations. The paper presents a number of the algorithms of their numerical realization together with the comparative analysis. The class of observation systems under investigation is bounded by ones with additive observation noises. This presumes that the observation noise intensity is a nonrandom constant. To construct the approximation, the authors use the left and midpoint rectangle rule of the accuracy order 2 and 3, respectively, and the Gaussian quadrature of the order 5. Finally, the presented numerical schemes have the accuracy of the order 1/2, 1, and 2.