A wireless receiver for receiving signals from a satellite positioning system, and receiving signals from a communications system uses a common path in the receiver, and derives position information (60, 230) from the received signals by correlation (50, 210, 220) with a code. In a first mode the deriving is carried out from the received signals excluding selected signals received in time slots used for communications signals. A second mode includes such signals. This enables control of the trade off between accuracy and the latency of the positioning processor to improve the performance over a range of conditions. The mode input can be changed dynamically according to signal strength, or according to the needs of an application.