Systems and methods are provided for location determination in wireless communication networks. A client device with a location provider installed is configured to provide location data to a data engine server and to obtain location service from a positioning engine server or the location provider itself. The location provider based on one or more components implements the reference data delivery function and the client location determination function. The data engine server is configured to process the location data received from one or more client devices and maintain a location database. The data engine server based on one or more components implements the reference data retrieval function, station position calculation function, reference data management function, and assistance data delivery function, as it interacts with the client device. The positioning engine server is configured to process the location request data received from one or more client devices and calculate the locations of the client devices. The positioning engine server based on one or more components implements the positioning data retrieval function and device position calculation function, as it interacts with the client device. The location database stores the previously obtained location data.