The global-scale communication network 100 uses free-space optical communications (FSOC), which is an optical communication technology that uses light propagating in free space to wirelessly transmit data. Therefore, the global-scale communication network 100 transmits a communication signal 20 wirelessly between two communication terminals 300, 400, 500.

A communication device 200 is included in each of the stationary communication terminals 300, the satellites 400, and the HAPs 500 that use FSOC. The communication devices 200a-f may be configured to establish an optical communication link 22 between two communication terminals 300, 400, 500 allowing a communication signal 20 to be transmitted from one communication terminal 300, 400, 500 to another. Once a communication link 22 is established between two communication devices 200, then a transmitting communication device, such as 200a, may transmit a communication signal 20 to a receiving communication device, such as 200b. In some examples, when a transmitting communication device, such as 200a, transmits a communication beam to establish a communication link 22 with a receiving communication device, such as 200b, it is desirable that the transmitting communication device 200a accurately transmits the communication beam so that the receiving communication device 200b accurately receives the communication beam. In some implementations, because of the distances between the communication devices 200a, 200b, a 0.001-degree accuracy may be needed to correctly establish the communication link 22.