Kaitai struct for AISTECHSAT-2. See https://community.libre.space/t/observation-3377133-aistechsat-2-43768/

aistechsat2

meta:
  id: aistechsat2
  file-extension: aistechsat2
  endian: be
seq:
  - id: magic # complete guess
    contents: [0x82, 0xf3, 0x9d, 0x00, 0x00, 0x11]
  - id: counter # this seems to be incrementing
    type: u1
  - id: unk1 # how much of this is header, how much is inside packet?
    size: 4
  - id: msg_type
    type: u1
  - id: unk2 # how much of this is header, how much is inside packet?
    size: 21
  - id: body
    type:
      switch-on: msg_type
      cases:
        0xc3: three_aircraft
        0xff: debug
types:
  chunk:
    seq:
      - id: hex
        type: u3
      - id: name
        type: str
        size: 10
        encoding: ascii
      - id: unknown
        size: 32
  three_aircraft:
    seq:
      - id: chunk1
        type: chunk
      - id: chunk2
        type: chunk
      - id: chunk3
        type: chunk
  debug:
    seq:
      - id: unk3
        size: 86
      - id: str
        type: str
        encoding: ascii
        size: 27 # or is this null-terminated?
  u3:
    seq:
      - id: high_byte
        type: u1
      - id: low_word
        type: u2
    instances:
      value:
        value: '(high_byte << 16) | low_word'