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As lasercom transitions from individual demonstrations to wide-spread deployment, diverging standards and proprietary implementations will impede interoperability between terminals from different suppliers. In this environment, there is an urgent need for a universal lasercom translator terminal capable of supporting multiple acquisition sequences and communication waveforms in order to connect disparate networks. Development of such a generalized terminal is a key goal of the DARPA Space-Based Adaptive Communication Node (Space-BACN) program. Pointing, Acquisition, and Tracking (PAT) are crucial aspects of interoperability, and multiple styles of PAT sequences have emerged. Even within a given category of beacon generation (e.g., synthesized, in-band, out-of-band), multiple parameters must be specified to define specific entry/exit criteria for each PAT stage, requiring detailed pre-coordination to ensure that terminals from different suppliers can establish a link between them. In addition, extra hardware must be incorporated into the terminal design to accommodate a superset of PAT requirements. Finally, verification testing of multiple PAT sequences in a common testbed drives the testbed implementation requirements. Here, we examine the implications of attempting to accommodate a generalized PAT sequence with a single lasercom terminal. First, we consider the performance of different styles of PAT sequence, and the trades between pointing uncertainty, maximum acquisition range, and allowable scan time. Next, we consider potential hardware requirements for terminals that support multiple PAT sequences. Finally, we consider the testing of such a terminal, and present a testbed architecture intended to accommodate multiple PAT sequences by highly flexible emulation of the remote terminal PAT behavior.
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