ocaml-aos#

CCSDS AOS (Advanced Orbiting Systems) Transfer Frame parser and encoder.

AOS frames are defined in CCSDS 732.0-B-4 and used for high-rate downlinks from satellites.

Installation#

opam install aos

Usage#

(* Decode an AOS frame *)
let () =
  let buf = (* ... frame bytes ... *) in
  match Aos.decode buf with
  | Error e -> Printf.printf "Error: %a\n" Aos.pp_error e
  | Ok frame ->
      Printf.printf "SCID: %d, VCID: %d, Data: %d bytes\n"
        (Aos.scid_to_int frame.header.scid)
        (Aos.vcid_to_int frame.header.vcid)
        (String.length frame.data)

(* Create and encode an AOS frame *)
let () =
  let scid = Aos.scid_exn 42 in
  let vcid = Aos.vcid_exn 5 in
  let frame = Aos.v ~scid ~vcid ~vcfc:12345 "payload data" in
  let encoded = Aos.encode frame in
  Printf.printf "Encoded: %d bytes\n" (String.length encoded)

(* Create a frame with CLCW *)
let () =
  let scid = Aos.scid_exn 42 in
  let vcid = Aos.vcid_exn 5 in
  let clcw_vcid = Clcw.vcid_exn 5 in
  let clcw = Clcw.v ~vcid:clcw_vcid ~report_value:100 () in
  let frame = Aos.with_clcw ~scid ~vcid ~vcfc:1 ~clcw "data" in
  let encoded = Aos.encode frame in
  Printf.printf "Frame with CLCW: %d bytes\n" (String.length encoded)

Frame Format#

Primary header (6 bytes):
  Byte 0-1: TFVN(2b) | SCID(8b) | VCID(6b)
  Byte 2-4: VC Frame Count (24b)
  Byte 5:   RF(1b) | SF(1b) | spare(2b) | VFCC(4b)

Optional insert zone (variable)
Data field (variable)
Optional OCF (4 bytes) - Contains CLCW
Optional FECF (2 bytes) - CRC-16-CCITT

Licence#

MIT