Techniques disclosed herein are generally directed toward providing customized location database information regarding terrestrial transceivers to a mobile device (e.g., a semi-connected mobile device) by causing the mobile device to scan for terrestrial transceivers during a first period of time, provide a list of the terrestrial transceivers detected during the first period of time to a location server, and receive location information for terrestrial transceivers on the list. Using this location information, the mobile device can subsequently (e.g., during a second period of time) calculate its position when the terrestrial transceivers are detected.