With the improvement of the data recording rate and higher requirements to the accuracy of the data, the traditional acquisition system cannot meet the new requirements, and it is urgent to use the new terminal and te...
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ISBN:
(纸本)9781728134031
With the improvement of the data recording rate and higher requirements to the accuracy of the data, the traditional acquisition system cannot meet the new requirements, and it is urgent to use the new terminal and technology. Mark6 is the latest recording terminal that is currently developed by MIT. It has been used by the main astronomical institutions, such as JIVE, KASI, Max-Planck-Institute and so on. This paper first introduced the VLBI data acquisition terminal and provides the debugging and configuration of the hardware and software of Mark6 in Shanghai Astronomical Observatory;Then, the data recording test and analysis of the interconnection between Mark6 and CDAS2 are introduced;Finally, the application of Mark6 system and the subsequent research and development of related software are briefly described. This paper can provide guidance and reference for the installation, configuration and upgrade of the follow-up terminal acquisition systems.
VLBI (Very Long Baseline Interferometry) technology is a high resolution astronomy observation method, which combines several telescopes to achieve the observation of a large telescope. Because of the high measurement...
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ISBN:
(纸本)9784885523168
VLBI (Very Long Baseline Interferometry) technology is a high resolution astronomy observation method, which combines several telescopes to achieve the observation of a large telescope. Because of the high measurement precision of VLBI observation technology, it is applied to accurate positioning of quasars and changes of baseline distance and direction within the measurement range of thousands of kilometers. As everybody knows, we provide the moon satellite orbit information by using VLBI observation technology. The VLBI digital backend is always the subject of the Shanghai astronomical observatory. And the core architecture of the hardware platform is the high-speed ADC+FPGA. With the rapid development of electronic technology and the gradual increase of astronomical demand, the upgrading of all kinds of astronomical digital backend is becoming more and more intense, which leads to make higher requirements for equipment development and maintenance cost. Shanghai astronomical observatory has developed a backend based on ROACH2 to realize the development of the VLBI digital baseband conversion. The hardware of ROACH2 is developed by CASPER organization and it is convenient to design firmware by using fundamental library provide by CASPER. To a certain extent, the time loss and cost loss caused by the development of hardware platform are reduced. There are several key technologies in the process of VLBI digital backend to be discussed based on ROACH2 hardware platform, including PFB algorithm, digital complex baseband signal to digital real baseband conversion function, mark5b formatter design, two bit optical threshold calculation. This VLBI backend has been carried out long baseline VLBI observation together with CDAS, which obtains perfect fringe result.
Dispatching Automation System (DAS) has been widely used in many critical areas such as power dispatch, transport dispatch, and water dispatch. It provides a reliable guarantee for the development of social economy, w...
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ISBN:
(纸本)9781538676721
Dispatching Automation System (DAS) has been widely used in many critical areas such as power dispatch, transport dispatch, and water dispatch. It provides a reliable guarantee for the development of social economy, which in turn puts forward higher quality requirements for DAS. Thus, security protection, which provides a basis for safe and stable operation, plays a crucial role in DAS. Although a number of studies focus on improving the protective ability of security on DAS, there is no comprehensive research on these techniques. To fill this gap, we conduct a preliminary research on DAS protection. In this paper, we present the DAS security risk taxonomy and reviews the corresponding protective works. Moreover, we also point out the future directions in DAS protection.
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