Design And Implemention Of The Satellite-ground TT&C Link Of Lilacsat-2

Micro/nano satellite is a hot issue in aerospace fieldnowdays. Comparing to traditional large satellites, micro-satellites and nano-satellites have advantages in low cost, short time and standlization. TT&C subsytem is one of the most critical subsystems of a satellite. Most of the micro/nano-satellites operates on VHF/UHF band. The channel protety of VHF/UHF band and the limition of size and power of a micro/nano-satellite proposed special requirements for the TT&C subsystemThis paper is based on a student satellite project of Harbin Institute of Technology, Lilac Sat-1. The work of this paper include:Design of the electronic system of Lilac Sat-2 based on mission requirements, and then design of the TT&C and RF subsystem. The electronic system was designed to be parallel, heteroideous and hot standby, and was single-point-failure-free in subsystem level. Grounding method and communication protocol were also analyzed and designed.Study of the VHF/UHF TTC channel property and s ystem design from the view of orbit, frequency, channel random process and transmitter mode. methods to improve channel peformance were proposed.A VHF/UHF TT&C transceiver suitable for micro/nano-satellite mission was designed based on SDR. The VHF/UHF transceiver used ZIF/LIF receiver and IQ direct modulation transmitter to achieve low power and small size. Along with corresponding software, telemetry, command and relay communications were implemented.Tracking algorithm was studied and the ground system based on SDR was designed. Miscellaneous tests were carried out based on this.In this study, the electronic system of Lilac Sat-2 was designed. A VHF/UHF transceiver based on SDR and its ground system was developed. The technical specifications and mission requirements were met.