The invention is directed to an apparatus and method for determining or estimating position using GPS signals. The system includes a receiver such as a GPS receiver for receiving GPS signals and a processor for determining position from the received GPS signals. The receiver receives a first GPS signal from a first GPS satellite at a first position of the first GPS satellite. A second GPS signal is received by the receiver from the first GPS satellite at a second position of the first GPS satellite. Position of the receiver is determined using the first and second GPS signals. Time differences between the two signals can be determined and used in calculating position.