A mathematical model of a pointing, acquisition, and tracking (PAT) system intended for laser-based intersatellite communication is developed and implemented in software in the form of a simulator. It represents major dynamic channels of the system and complex interaction of operational conditions, disturbances, and design parameters thus facilitating the solution of various analysis, design, and control problems. Application of computer graphics and animated schematics, driven by the model, provides accurate display of the most intricate phenomena behind the PAT operation. Coupled with a working laboratory prototype of the PAT system through a data communication board, the simulator is capable of displaying both simulated and real variables serving as a diagnostic tool. The simulator has been applied for development and verification of a novel jitter compensation scheme.