Method, mobile device, computer program product, and apparatus for optimizing sensor reporting are described. A mobile device can measure radio frequency (RF) signal characteristics while receiving data from one or more mobile device sensors. The mobile device may determine its relative displacement between RF signal measurements. The mobile device can send a representation of the RF signal characteristics and the displacement data to one or more servers. The representation displacement data may include one or more reliability characteristics and/or a displacement reliability rating. A server can obtain the displacement data and RF signal characteristics to determine positioning of wireless transmitters in an environment and build a positioning database.