Arnon S, Rotman S R, Kopeika N S
Appl Opt. 1998 Sep 20;37(27):6366-74. doi: 10.1364/ao.37.006366.
Free-space optical communication between satellites in a distributed network can permit high data rates of communication between different places on Earth. To establish optical communication between any two satellites requires that the line of sight of their optics be aligned during the entire communication time. Because of the large distance between the satellites and the alignment accuracy required, the pointing from one satellite to another is complicated because of vibrations of the pointing system caused by two fundamental stochastic mechanisms: tracking noise created by the electro-optic tracker and vibrations derived from mechanical components. Vibration of the transmitter beam in the receiver plane causes a decrease in the received optical power. Vibrations of the receiver telescope relative to the received beam decrease the heterodyne mixing efficiency. These two factors increase the bit-error rate of a coherent detection network. We derive simple mathematical models of the network bit-error rate versus the system parameters and the transmitter and receiver vibration statistics. An example of a practical optical heterodyne free-space satellite optical communication network is presented. From this research it is clear that even low-amplitude vibration of the satellite-pointing systems dramatically decreases network performance.
分布式网络中卫星间的自由空间光通信能够实现地球上不同地点之间的高数据率通信。要在任意两颗卫星之间建立光通信，需要在整个通信时间内使它们的光学视线对准。由于卫星之间距离遥远且需要对准精度，一颗卫星指向另一颗卫星的指向操作很复杂，这是由两种基本随机机制导致的指向系统振动引起的：电光跟踪器产生的跟踪噪声以及机械部件产生的振动。发射光束在接收平面内的振动会导致接收光功率下降。接收望远镜相对于接收光束的振动会降低外差混频效率。这两个因素会增加相干检测网络的误码率。我们推导了网络误码率与系统参数以及发射机和接收机振动统计量之间的简单数学模型。给出了一个实际的光学外差自由空间卫星光通信网络的示例。从这项研究可以清楚地看出，即使卫星指向系统的低幅度振动也会显著降低网络性能。
