Abstract: A client device is configured to (i) based on initial sensor data and a road network graph maintained on the client device, determine a set of particles corresponding to the road network graph, each particle including a (a) trajectory along the road network graph, (b) position and velocity, and (c) probability, (ii) identify a particle with a highest probability, (iii) based on the identified particle, determine the location of the client device in the road network graph, (iv) after receiving new sensor data, extend the trajectory of each particle, (v) based on the new sensor data, update, for each particle (a) the position and velocity and (b) the probability, (vi) identify a particle from the second updated set of particles with a highest probability, and (vii) based on the identified particle, determine the updated location of the client device in the road network graph.