A mobile device may use one or more outlier detectors to detect likelihoods that an outlier condition exists for a satellite positioning system (SPS) position fix. In some implementations, an outlier detector may compare a computed position fix to an element of assistance data to generate an outlier likelihood. A decision to perform a recovery operation may be made based, at least in part, on a generated outlier likelihood. In some implementations, a computed reliability of the position fix may also be considered in making a recovery decision.