A system for tracking a state of a GNSS receiver uses a subset of the measurements of satellite signals selected to avoid the need for intermediate integers ambiguity estimate. The system selects the subset of measurements for the state tracking such that each measurement in the selected subset of measurements is formed by a weighted combination of multiple different measurements from the set of measurements. The system uses a probabilistic state estimator that tracks the state of the GNSS receiver using a probabilistic motion model subject to noise and a probabilistic measurement model relating the selected subset of the measurements of satellite signals to the current state of the receiver.