A First-Estimates Jacobian EKF for Improving SLAM Consistency

Guoquan P. Huang, Anastasios I. Mourikis, Stergios I. Roumeliotis

Research output: Chapter in Book/Report/Conference proceedingConference contribution

61 Scopus citations


In this work, we study the inconsistency of EKF-based SLAM from the perspective of observability. We analytically prove that when the Jacobians of the system and measurement models are evaluated at the latest state estimates during every time step, the linearized error-state system employed in the EKF has observable subspace of dimension higher than that of the actual, nonlinear, SLAM system. As a result, the covariance estimates of the EKF undergo reduction in directions of the state space where no information is available, which is a primary cause of the inconsistency. Furthermore, a new "First-Estimates Jacobian" (FEJ) EKF is proposed to improve the estimator's consistency during SLAM. The proposed algorithm performs better in terms of consistency, because when the filter Jacobians are calculated using the first-ever available estimates for each state variable, the error-state system model has an observable subspace of the same dimension as the underlying nonlinear SLAM system. The theoretical analysis is validated through both simulations and experiments.

Original languageEnglish (US)
Title of host publicationExperimental Robotics - The Eleventh International Symposium
Number of pages10
StatePublished - 2009
Event11th International Symposium on Experimental Robotics, ISER 2008 - Athens, Greece
Duration: Jul 13 2008Jul 16 2008

Publication series

NameSpringer Tracts in Advanced Robotics
ISSN (Print)1610-7438
ISSN (Electronic)1610-742X


Other11th International Symposium on Experimental Robotics, ISER 2008


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