A Design of Navigation Enhancement Signal Based on Communication Satellite Signal

For the needs of navigation users for ubiquitous and reliable PNT (positioning navigation and timing) services, we can utilize the global coverage of communication satellite system and its differences with navigation constellation in orbit, frequency and intensity of signal and adopt the mode of integrated into the communication system to realize the navigation enhancement, supplement new space-based navigation nodes with high efficiency cast ratio. At the transmitting end of communication satellite signal, the idle time slot of the communication service signal broadcasting period is used and the communication service frame format is not changed. The downlink spectrum resources of the communication service are allocated as needed to broadcast signal that modulate a known fixed symbol in the data domain. The user terminal generates the same modulation symbol locally, coherently accumulates multiple sub-band signals broadcast by the same beam, and performs correlation processing with the received data, so as to realize high precision code phase alignment and complete the pseudorange measurement function. The performance of navigation enhancement signal based on a downlink signal data format of L-band mobile communication is simulated. The results show that the acquisition and tracking of the signal can be realized by using the auto-correlation characteristics of the scrambling code of the communication signal. Multiple sub-band coherent synthesis can achieve ranging and frequency measurement performance close to GNSS Open Service Performance signal and It also has higher capture margin. We take a communication technology test satellite as the verification platform, the broadcasting and acquisition of single sub-band and six sub-bands navigation enhancement signal were carried out, and the receiving processing and ranging performance analysis are carried out after the acquisition data are superimposed with Doppler frequency offset, pseudorange variation and noise. The results are consistent with the theoretical simulation, which verifies the engineering feasibility of the signal enhancement scheme proposed in this paper.