Signals of opportunity in mobile radio positioning

In this paper we address the benefit of observing a signal of opportunity for mobile terminal positioning. In an exemplary environment we arrange three mobile terminals in an equilateral triangle. These mobile terminals determine their position relatively to each other by transmitting and receiving mobile radio signals. In addition they observe a signal of opportunity which is emitted from a transmitter. In our case this signal is a single carrier. We evaluate the performance improvement for positioning of the mobile terminals when observing such a signal of opportunity. The evaluation is based on the calculation of the Cramér-Rao lower bound. For an exemplary environment with three mobile terminals and one signal of opportunity a performance gain of up to ≈ 38.8 % can be expected theoretically.