Theoretical approach for the optimization of pseudolite pulsing scheme and the implementation of participative receivers

The availability and position estimation performance of global navigation satellite systems (GNSS) can be enhanced with ground-based ranging sources, called pseudolites. Because of the high relative power of their signals, they usually transmit pulsed signals. In this way their interference on the satellite signals is restricted to only a fraction of time (duty cycle). To avoid mutual interference between pseudolite signals, pseudolite pulsing schemes have been designed such that the overlapping of the pulses from different pseudolites is minimized. In this paper the intentional overlapping of pseudolite pulses is proposed. It is shown that theoretically the pseudolite ranging performance is degraded only little if the pulses overlap. By using two variants of interference cancelation techniques, it is furthermore demonstrated that there exist receiver architectures which can still achieve a performance close to the theoretical limits. Therefore the overlapping of pseudolite pulses reduces the degradation of the satellite signal but still offers a high achievable accuracy of the pseudolite ranging signals.