Estimating the accuracy of satellite ephemerides using the bootstrap method

Context. The accuracy of predicted orbital positions depends on the quality of the theorical model and of the observations used to fit the model. During the period of observations, this accuracy can be estimated through comparison with observations. Outside this period, the estimation remains difficult. Many methods have been developed for asteroid ephemerides in order to evaluate this accuracy. Aims. This paper introduces a new method to estimate the accuracy of predicted positions at any time, in particular outside the observation period. Methods. This new method is based upon a bootstrap resampling and allows this estimation with minimal assumptions. Results. The method was applied to two of the main Saturnian satellites, Mimas and Titan, and compared with other methods used previously for asteroids. The bootstrap resampling is a robust and practical method for estimating the accuracy of predicted positions.