Probabilistic model for a positioning technique

A model construction module for constructing a probabilistic model of a wireless environment in which a target device communicates using signals that have a measurable signal value, such as signal strength. The model construction module forms several submodels of the wireless environment. Each submodel indicates a probability distribution for signal values at one or more locations in the wireless environment. The module combines the submodels to a probabilistic model of the wireless environment, such that the probabilistic model indicates a probability distribution for signal values at several locations in the wireless environment. Alternatively, the model may insert new locations to a single model based on a combination of existing locations. The combination of submodels or existing locations includes combining the inverse cumulative distribution functions of the submodels or existing locations.