STANAG-4481 PSK (4481-P) is basically a STANAG-4285 sub-mode which adopts fixed 300 bps data-rate and long interleaving. As well as 4285, 4481-P is mostly used in NATO Naval broadcast due to its repeated preamble for which it's easy to maintain sync during long transmissions.
In the heard transmission, spotted on 8322.2 KHz/USB, it's interesting to note the presence of the 64-bit KG84 sync pattern into the demodulated bitstream (Fig. 2)
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| Fig. 1 |
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| Fig. 2 |
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