The Space Solar Telescope (SST) is a very important astronomical satellite project in China. It will carry five observing instruments with the main optical telescope's aperture up to 1m to 'see' the sun simultaneously in different wave bands of white light, UV light, hard X-ray, soft X-ray, Hα line and radio emission etc. The quantity of the scientific data(after being preprocessed such as integration) collected by CCDs and other sensors of the five payloads every day will reach 50Gbytes. The huge data will be then compressed to about 8Gbytes by a data compression system and saved in a mass memory system. So we need to transmit the scientific data down to satellite ground station at a bit rate of 60Mpbs within about 43minutes. In this paper, a high rate scientific data transmission system (DTS) is introduced as follows: Firstly, the DTS is designed and its characteristics are studied and analyzed comprehensively according to the requirements of the SST. Secondly, the Channel Encoding-Decoding unit of the DTS is designed and developed. The Channel Encoding unit will be used to translate the parallel data stored in the Mass Memory into two streams of serial formatted data, which are fit for QPSK radio modulation, and the Channel Decoding unit will be used to realize the reversed processes. Some new ideas of communication system are included in the designs. And the protocol of this system is completely compatible with that of the existent satellite ground station. Thirdly, ground experiments on the Channel Encoding-Decoding unit's base-band link system are made. As results, the specifications of the Channel Encoding-Decoding unit have perfectly fulfilled the requirements of the SST, among which no error exists in ideal no-noise situation and the data rate has reached 60Mpbs-the highest data transmission rate at present in satellite scientific data transmission systems in China. Fourthly, software simulation is an important process to guarantee scheme design. Several simulations on methods, principles and hardware designs are given. At last, the principle, method and laboratory test results of developing the Channel Encoding-Decoding unit are also given in details in the paper.
修改评论