A Method for the Navigation Satellite Signal Enhancement Based on the Signal Retransmission by the Communication Satellite

A method based on the signal retransmission by the Geostationary Earth Orbit (GEO) comsat for the navigation satellite signal enhancement is proposed. At the signal transmitting side, utilizing the property of low power density of the Direct Sequence Spread Spectrum (DSSS), the power-controlled weak DSSS navigation signal, which is generated at the navigation center, can be modulated and retransmitted on the frequency band of the GEO comsat under the proper Bit Error Rate (BER) requirement of the communication signal. While at the receiving side, with the FREquency-SHift (FRESH) filter and a given adaptive signal cancellation algorithm, the strong communication signal can be well cancelled and thus the weak navigation enhanced signal is separated. The simulation results show that for the separated navigation enhanced signal, a relatively good acquisition and tracking performance can be got in its controlled power range, and this also verifies the effectiveness of the proposed method.