Research And Implementation Of Ground Test System For Quantum Communication Payload On Space Platform

Quantum information science is a new cross-field subject formed by the quantum physics andclassical informatics. It has been recently attracting world-wide attention and research for itsunique advantages and prospects. Quantum cryptography (more accurately should be called"quantum key distribution", QKD) is the fastest growing and the most applicable subject inquantum information science. Currently, quantum communication through the fiber channel hasbasically reached the limit transmission distance. While stable and low loss free-space channelthrough space platform open the door for long distance QKD, which become the most popularresearch direction.Accordingly, adequate test must be executed in order to guarantee the effectiveness andstability of the QKD payload`s function. This is the significance of our ground inspection systemdesign. The system, which analogs the signal input of space platform, control payload to completethe operation of quantum communication, monitor and parse payload`s status. Ground detectsystem plays an important role in the development process of the quantum communication payload.A simple and universal system is proposed in this paper. According to the communicationprotocol of space platform and quantum communication payload, the system supports the RS-422communication interface, LVDS digital control interface, analog telemetry interface, direct OCpulse command interface. The interface hardware, designed in PCI board, is connected withindustrial control computer by PCI bus of computer`s main board. The stable and reliableperformance is the most important vantage, as well as its clear and simple structure and smalldesign workload. The ground test system software can be divided into5modules: interface module,control module, the command file import and export module, process data recording and replaymodule, parameter information dynamic configuration module. The first two modules can becomposed of the most simple system, control module perform QKD payload correspondingoperation through the interface module, at the same time, receiving and analyzing payload runningstate. But the last three modules is the essence of the system. The command file import and exportmodule is responsible for the command data storage, as we can directly import commands withoutadd again when performs a similar test. Process data recording and replay module refers that theinspection system automatically sending command to payload according to the preset time, meanwhile command data and payload status data were recorded in the log file. It realizes theautomatic testing as we can view payload running status through replaying the log file. Parameterinformation dynamic configuration module will deploy command set and payload status analysisformat through external configuration files. Not only makes easy for modify as the payload andplatform protocol change, but also for other payload test work.The ground inspection system has been used in practice. With simple operation, humanizationdesign, stable running, and well adapted to the payload and space platform frequent changes of theagreement, it plays an important role in the process of development of quantum communicationpayload. Finally, we reviewed the main work of this paper. Pieces of advice are putted forward tomake inspection system more intelligent and more humanistic. This is the prospection of theground inspection system.