Optical Wirless Links For Intra-Satellite Communication:Codeing Design And Bus Technology Of Data Handling System

Optical Wirless Links for intra-Satellite communications (OWLS) use the infrared light instead of the traditional data cables or radio-frequency as an information carrier medium to achieve data transfer and information management between the payloads which are fixed within the satellite. In the space environment that with the complex structure and confined space, the benefits of wireless communication systems are: mass reduction, low power consumption, wide bandwidth, flexibility, the lack of Electro-Magnetic Interference/Compatibility (EMI/EMC), and simplification of the Assembly, Integration and Tests phases (AIT). Considering the specificity of the space environment such as vacuum and high-energy particle radiation, the on-orbit application of the optical wireless links should also solve the space adaptability problems of optoelectronic devices. This paper has researched the critical technology in OWLS:communication protocol, modulation and multi-access and radiation-hardening design for optoelectronic devices.First, the network structure of the OWLS is presented, and various communication buses used in the satellite such as1553, Controller Area Network (CAN), Serial Peripheral Interface (SPI) and special communication protocol for housekeeping sensors are investigated. This work use Optical Code Division Multiple Access (OCDMA) technology instead of current time division multiple access technology to complete data management for mass housekeeping sensors. In chapter three, several normal optical codes are contrasted, and optical orthogonal code is chosen as the address code in OCDMA system, and the codec design of the sensor information collection system is described, the design is realized on Field Programmable Gata Array (FPGA) by hardware description language Verilog. Cooperating with infrared wireless communication, the OCDMA system totally meet the requirement of mass reduction and low power consumption in satellite.Then, in chapter four, the conversion interface which is used between SPI bus that has four signals and optical wireless transceiver that has only one signal is presented. The design of conversion interface is described by Verilog, and it is based on the System on Programmable Chip (SOPC). The design overcomes the metastable state problem caused by Cross Clock Domain transfer in original design. The communication function testing shows that the design can meet the requirements of high reliability within satellite communication. In chapter five, the space radiation effects are described, and radiation-hardening design for optoelectronic devices is presented.Finally, the work of research is summarized, and further activities are discussed.