Real-Time Correlator Technologies of VLBI

Abstract

Real-time correlator is the core facility of data processing center of China’s Lunar Exploration Project (CLEP) VLBI subsystem. Software and hardware ones are developed to ensure the successful tracking in all CLEP missions by the main and standby operation mode. The software correlator is a specially designed parallel computing program which runs on a high performance cluster server platform. The hardware one is a special high speed signal correlator based on a FPGA platform. They all adopt FX type structure，with real-time data receiving，decoding，correlation processing，phase correction signal extraction，real-time monitoring and other functions. When the accuracy of the prediction delay model is not enough，the correlator can reconstruct the delay model automatically by the special fringe search module and the processor is guided to complete the related processing of the detector signal. After engineering verification, the real-time data rate of the Lunar probe VLBI measurement orbit reached 512 Mbps.

Key words： VLBI; software correlator; hard ware correlator; parallel computing; fringe search

References

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