A location of a mobile device in a venue can be estimated by using a state space estimator to determine candidate locations of the mobile device at a first time point based on previous candidate positions conditioned upon an observation of one or more environmental variables. A second observation is received at a second time point, and the state space estimator performs a propagation step to determine the candidate locations at the second time point based on the candidate locations at the first time point and the second observation. The propagation step includes a plurality of sub-propagation steps in which a time length between the sub-propagation steps is a fraction of the time length between the first and second time points, and at each sub-propagation step each candidate location is propagated according to a stochastic process. The location of the mobile device at the second time point is determined based on the candidate locations at the second time point.