Study on Spacecraft Communication and Ranging technologies over Ultra-Long Distance for Future Jupiter Mission

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The better receiver sensitivity, incorporation of turbo coding scheme based on it, and improved ranging link capability through onboard regenerative operation are necessary for the future Jupiter mission program to be conducted by JAXA. In our research, we have built and verified our ground station system model to demonstrate the better performance of our new receiver, to develop our circuit board for turbo coding, and to complete our first regenerative ranging system combining it with our pre-developed onboard transponder model.The ground station model was constructed as a set of circuit board on VME bus system, which contains all the Junctions ranging from A/D converter to follow IF signals down-converted from S-band to any necessary receiver capabilities like demodulation and decoding. Narrower PLL bandwidth in carrier capturing and its stable operation were designed to enable demodulation of residual carrier PM modulation signals at much lower input level than ever. The hardware loss through the carrier acquisition to symbol synchronization was evaluated to be less than 0.1dB with the input of -0.2dB of S/N. This input level condition corresponds to the requirement of CCSDS turbo coding definition. It means that our newly developed receiver works well as one for turbo coding scheme.The ranging system was introduced as a part of our ground station model. It was a first demonstrator of our regenerative ranging scheme, which leads to more than 15 dB improved ranging link with the use of our new deep space transponder.