Synchronisation method for pulsed pseudolite positioning signal under the pulse scheme without slot-permutation

摘要

Ground-based pseudolite positioning systems are valuable in environments where global positioning system (GPS) is not available. To mitigate near-far effect, pseudolite positioning systems often use pulsed signals instead of GPS-like continuous signals. The simple pulse scheme without slot-permutation cannot preserve the spectrum shape of the original un-pulsed signal, and this may result in false frequency-lock in the receiver. Complicated pseudorandom pulse schemes are often used to avoid false frequency-lock, which increases acquisition and tracking complexity. The synchronisation method presented in this study can acquire and track pulsed signals without false frequency-lock under the pulse scheme without slot-permutation, which enables the use of this pulse scheme in pseudolite positioning systems and is useful for reducing complexity of transmitter and receiver. Simulation results show that the presented method can track code phase, carrier phase and Doppler frequency accurately and correctly.