A wi-fi based mobile positioning system determines mobile device positioning by count stamped packets communicated between the mobile device and access points according to a standard wifi protocol. Ad-hoc groups of wifi network nodes are formed and then broken with a mobile device as that mobile devices moves relative to fixed nodes, such as access points. Within an ad-hoc group, the nodes count stamp packets by latching a local counter within each node. Count-stamps are collected and used to generate ranges for a mobile device relative to nodes in an ad hoc group. A positioning services determines the position of the mobile device from the ranges.