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PAT - Pointing, Acquisition and Tracking
What is PAT?
(Pointing, Acquisition and Tracking)
Pointing, Acquisition and Tracking (PAT) is the set of technologies and control functions used to establish and maintain precise alignment between two optical terminals. In free-space optical communication, PAT systems ensure that a narrow laser beam is correctly directed toward the receiving terminal and remains aligned despite relative motion, vibration, and other disturbances.
PAT is particularly critical for laser communication in space, where narrow optical beams require extremely accurate angular alignment between satellites or between spacecraft and ground stations.
How Pointing, Acquisition and Tracking Works
A PAT system first identifies the remote optical terminal, establishes the initial alignment, and then continuously corrects the pointing direction to maintain the optical link.
Pointing
The transmitting terminal directs its optical beam toward the expected position of the receiving terminal using available position and attitude information.
Acquisition
The system searches for and detects the remote terminal, then refines the alignment until the optical terminals are accurately aligned.
Tracking
Once the link is established, sensors continuously measure alignment errors and the control system adjusts the pointing mechanism to compensate for spacecraft motion, vibration, and other disturbances.
