Localization and navigation systems and techniques are described. An electronic device comprises a processor configured to apply an extended Kalman filter (EKF) as the electronic device traverses the trajectory. The extended Kalman filter is configured to maintain a state vector storing estimates for a position of the electronic device at poses along a trajectory within an environment along with estimates for positions for one or more features within the environment. The EKF computes constraints based on features observed from multiple poses along the trajectory, and updates, in accordance with motion data and the one or more computed constraints, the estimates within the state vector of the extended Kalman filter while excluding, from the state vector, state estimates for positions within the environment for the features that were observed from the multiple poses and for which the constraints were computed.