航天应用载荷的高精度时间同步与共用信息分发

应用载荷直接获取航天器平台的时间和公共测量信息,并不能完全满足载荷的高精度时间基准和共用信息使用需求。一些功能载荷具备向外输出高精度时间和状态测量信息的能力,但硬件接口资源有限。将功能载荷作为FC-AE-1553光纤网络的一个节点,在FC-AE-1553光纤网络中叠加IEEE 1588v2时间同步协议,功能载荷的高精度时钟源能同步给有需求的其他载荷。并在时间同步的前提下,将功能载荷的测量数据如定位数据、姿态数据和轨道数据等共用信息同步发送至网络上的其他载荷节点。通过时间同步与同步发送机制,解决了各载荷对高精度时间和共用信息的需求,弥补了专用信息硬件接口资源的不足。结果表明,与直接利用航天器平台的信息源相比较,当时钟源和共用信息来自功能载荷时,FC-AE-1553网络时间同步之后的时间基准精度和共用信息利用性能高出3个数量级,载荷获取的UTC时间精度达到百纳

High precision time synchronization and public information distribution for space utilization payload

For payloads with high requirements in time reference precision and public information, the general time data and public telemetry data provided by spacecraft platform is not sufficient. In contrast, some functional payloads have ability to output high-precision time and state measurement information, but their hardware interface resources are limited. To synchronize high-precision clock source of functional payload to other payloads with needs, the IEEE 1588v2 time synchronization protocol can be stacked into an optical fiber FC-AE-1553 network. Measurement information provided by the functional payload, such as location, attitude and orbit data, was then able to be sent to each payload NT terminal nodes distributed in whole network. A protocol was proposed to meet the demand of high precision time and public information of payloads, and also to avoid the resource information interface limitation of functional payloads. Design verification was carried out and the result shows that time data and public information supplied by the functional payload can successfully be sent to each node after the FC-AE-1553 network synchronization. The precision of data accepted by payload is three orders of magnitude higher compared with the information source of spacecraft platform, and the accuracy of UTC(universal time coordinated) time accepted is up to 100 ns.