1. A method, comprising: intercepting network requests sent from a user device via a network to a plurality of network devices, wherein the network requests include embedded position data generated by the user device and representing locations of the user device; extracting, from the intercepted network requests over a time period, the embedded position data of the user device and forwarding the intercepted network requests to the plurality of network devices; receiving, from another network device, baseline position data representing the locations of the user device over the time period, wherein the baseline position data is generated by the other network device using signals exchanged between the user device and one or more wireless access points associated with the network; generating a probability density estimate of the locations of the user device based on a kernel density estimator using the baseline position data; determining accuracy scores for the embedded position data using the probability density estimate of the locations; and filtering the embedded position data to remove outliers from the embedded position data using the determined accuracy scores.