Design of a pulsing scheme for BeiDou pseudolites signals

BeiDou pseudolites (BPLs), ground-based BeiDou-like signals transmitters, are capable of augmenting positioning accuracy, reliability, availability of the BeiDou satellite navigation system. However, implementation of the BPLs lead to another problem — the “near far problem”, where the satellite signals are blocked by the signals from a BPL. One of the promising solutions is to pulse the BPL signals to reduce the interference. Because the existing pulsing schemes, i.e., the RTCM SC-104 and the RTCA SC-159 are designed for the GPS signals, they cannot be simply adopted in the BeiDou system due to the different signal structures. Therefore, a dedicated BPLs signals pulsing scheme is proposed in this paper. Two critical parameters-duty cycle and pulse pattern which characterize a pulsing scheme are analyzed and determined in the proposed scheme. Besides, the transmission power requirement is explained in details. The simulation proves that this scheme meets all identified requirements, making it a viable solution to mitigate the near-far problem.