Abstracts

SSRT - specialized solar radio telescope, one from the largest astronomical tools intended for study of solar activity in a microwave range (5,7 GHz). The sensitivity of SSRT allows to observe active areas on all stages of their development on a hum noise of a radiation of undisturbed solar atmosphere. For deriving radioimages of weak detailses in atmosphere of the Sun the accumulation of signals in a full band of a reception of the radio telescope is used. Quick frequency radiation of flashes is registered on additive linear interferometers, of which SSRT consists.

The regular observations of the Sun on SSRT allow to have daily datas in a radiorange. The SSRT archives contain datas of one-dimensional observations (since 1985), two-dimensional radiomaps (since 1996), since 1992 the researches of fast processes ("spikes") are conducted. Volume of datas for day of observation, seasonally, order of 300 Mb. The outcomes of observations, both original, and containing outcomes of processing (for example, two-dimensional maps of the Sun) are noted on CD-carriers. On the present time the data file on CD-carriers makes about 200 Gb.

The SSRT datas integrally included into a data set of world centres. For broad data exchange with russian and foreign centres the information Web-server of a radioastrophysical observatory (http://ssrt.iszf.irk.ru) in Irkutsk is created. For operating access to the SSRT data the Information System of common use basing on use of the Internet information service is developed.

Large cost of digital archives and low bandwidth of the data links have caused necessity of software engineering ensuring effective lossless compression of represented data.

The high compression rate of data, arriving from the radio telescope, can be reached with the help of an algorithm which is taking into account characteristics of SSRT datas. Developed data-flow codec is designed for fast encoding-decoding and provides a possibility of easy hardware realization.

The base encoder uses a constant size of the block optimized on sampling rate of input. The datas, splits on blocks, pass through interchannel decorellation and transmitted further on a forecasting stage. On this stage the modelling(simulation) of a source signal is carried out with the help of 4-th stages adaptive filter. On the encoder of an entropy is transmitted a difference between an original and forecasted signal. The residual signal is compressed with use of the Rice codes. The realized compressor creates streams of a size, smaller on a comparison with output streams of majority of known programs, has the simple interface, ensures a high velocity and convenience of work with datas.

With the purposes of convenience of an integration of a format in other applications the dynamic library of the compressor is developed.

Note. Abstracts are published in author's edition

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