The Link Analyzation And Design Based On CCSDS For Mars Probe TTC&C System

Mars exploring is a very complicated and risky aerospace engineering.How to ensure that the probe in the huge distant can still finish the mission,TTC&C system plays the key role in the information transporting betweenprobe and earth.This paper comes from the subject of a Mars probe. Conditioning of basicdesign input of the subject's TTC&C system, this paper first discussed thebasic the up&down link's budget under the physical radio channel; then further,according to the probe's actual orbit, make the simulation and analysis for thedistance between the spacecraft and earth, the performance of communicationdata rate, and thus to define the entire process of the data rate switchingscheme; and the most of all, based on the simulation analysis of the visibilitytime of the station, to identify ground stations supporting plan fo the variousflight stage; finally, make the analysis for the communication availabilitydegree influenced by the solar conjunction and the shelter of the Mars, and thescientific exploration period that around the Mars, and the supportingavailability of VLBI measurement in the probe's whole life period, etc.Based on the system simulation and analysis of the communication link,this paper provides the basis for the TTC&C system onboard to carrying intocomprehensive engineering design. This paper makes the calculation of thedegree for communication link's influenced by factors like the distance,antenna form, communication data transmission and coding modulation mode,and provides a new data rate shifting method. Besides, this paper analyzes themain space process scenes the probe in orbit will meet in, and then makes theconcrete analysis and calculation about the availability and efficiency under the scenes of the communication, which determined the best settings ofsystem's parameters.Based on the analysis and calculation, this paper's makes the sense for thekey aspects of content for the Mars probe's communication during the wholelife period; and the effectively evaluation for the probe's communications link;and so as it to be the basis of coordination when negotiating with partner likecarrier or the ground measurement and control system etc.