Parallel Software Correlator Based on Multi-Core PC Servers and Computer Cluster

The Chinese Very Long Baseline Interferometry (VLBI) network (CVN) is a synthetic aperture radio telescope with the equivalent diameter up to 3000 Km. This telescope aims to astronomy observations and deep space explorations. The correlator is the kernel data processor, and its operation is both data intensive and computation intensive. This paper presents the structures of two CVN software correlators and their applications. One software correlator based on the multi-core PC server played an irreplaceable role in CE-1, the just finished Chinese lunar exploration mission. After the scan-based modification, this correlator got the first CVN pulsar image. The research of another powerful high speed software correlator based on the cutting-edge computer cluster was carried out to fulfill the CVN astronomical and geodetic applications in the near future. As the first Chinese Gigabit VLBI correlator, the prototype high speed software correlator demonstrated its ability in the first CVN 256Mbps e-VLBI experiment.