Conformance Statement for pkg/aos, CCSDS 732.0-B-4
A1.1 GENERAL INFORMATION
A1.1.1 Identification of PICS
| Field | Value |
|---|---|
| Date of Statement (DD/MM/YYYY) | 23/08/2026 |
| PICS Serial Number | ASTRO-AOS-PICS-001 |
| System Conformance Statement Cross-Reference | This document |
A1.1.2 Identification of Implementation Under Test (IUT)
| Field | Value |
|---|---|
| Implementation Name | astro/pkg/aos |
| Implementation Version | See go.mod / latest commit on main |
| Special Configuration | None |
| Other Information | Go library implementing CCSDS AOS Space Data Link Protocol. Full pipeline: PhysicalChannel (MC mux/demux) -> MasterChannel (VC mux, 24-bit gap detection) -> VirtualChannel (frame buffer) -> Services (M_PDU with packet spanning via FHP and SPP idle-packet fill, B_PDU with bitstream pointer, VCA with exact-fill SDUs, VCF for raw frame ingest). Partial M_PDU packet zones are completed with SPP idle packets (APID 0x7FF) per clause 4.1.4.2.2; oversized partial B_PDU payloads split across frames rather than clamping the pointer; the idle fill pattern is configurable per channel. |
A1.1.3 Identification of Supplier
| Field | Value |
|---|---|
| Supplier | Ravi Suhag |
| Contact Point for Queries | GitHub, github.com/ravisuhag/astro |
| Implementation Name(s) and Version(s) | astro/pkg/aos (Go package) |
| System Name(s) | Astro |
A1.1.4 Identification of Specification
| Field | Value |
|---|---|
| Specification | CCSDS 732.0-B-4 (AOS Space Data Link Protocol, Blue Book, Issue 4, August 2021) |
| Have any exceptions been required? | Yes [ ] No [X] |
A1.2 PROTOCOL FEATURES
| Feature | Reference | Status | Support |
|---|---|---|---|
| Transfer Frame Version Number | clause 4.1.2.2 | M | |
Y: TFVN = 1 (0b01) | |||
| Spacecraft Identifier | clause 4.1.2.3 | M | |
Y: 8-bit SCID (0-255) | |||
| Virtual Channel Identifier | clause 4.1.2.4 | M | |
Y: 6-bit VCID (0-63) | |||
| Virtual Channel Frame Count | clause 4.1.2.5 | M | |
Y: 24-bit per-VC counter with wrap | |||
| Replay Flag | clause 4.1.2.5.2 | M | |
Y: 1-bit signaling field | |||
| VC Frame Count Usage Flag | clause 4.1.2.5.3 | M | |
Y: 1-bit signaling field | |||
| Signaling Reserved Spares | clause 4.1.2.5.4 | M | |
Y: encoded as '00'; validated on decode | |||
| VC Frame Count Cycle | clause 4.1.2.5.5 | M | |
Y: 4-bit signaling field | |||
| Frame Header Error Control | clause 4.1.2.6 | O | |
Y: RS(10,6) over GF(2^4); check symbols generated on encode, verified on decode (error detection; correction of up to E=2 symbols not performed, failing frames are rejected) | |||
| Insert Zone | clause 4.1.3 | O | |
Y: Fixed length per physical channel | |||
| Transfer Frame Data Field | clause 4.1.4 | M | |
Y: Carries M_PDU, B_PDU, or VCA | |||
| Operational Control Field | clause 4.1.5 | O | |
Y: Optional 4-byte OCF | |||
| Frame Error Control Field | clause 4.1.6 | O | |
Y: CRC-16-CCITT | |||
A1.3 SERVICES
| Feature | Reference | Status | Support |
|---|---|---|---|
| Multiplexing PDU (M_PDU) | clause 3.3.2 | O | |
Y: Packet spanning with FHP-based resync; partial packet zones completed with SPP idle packets, discarded by APID on extraction | |||
| Bitstream PDU (B_PDU) | clause 3.3.3 | O | |
Y: Bitstream Data Pointer with full/partial frames; partials larger than the pointer can express are split across frames | |||
| Virtual Channel Access (VCA) | clause 3.3.4 | O | |
Y: Constant-length SDU exactly fills the data field; short/long SDUs rejected | |||
| Virtual Channel Frame (VCF) | clause 3.3.5 | O | |
Y: Raw frame ingest/emit | |||
| Only Idle Data (OID) | clause 4.1.2.4 | M | |
Y: VCID 63 reserved; idle frames run their own VC 63 frame count; fill pattern configurable | |||
A1.4 CHANNEL MANAGEMENT
| Feature | Reference | Status | Support |
|---|---|---|---|
| Physical Channel | clause 3.2.1 | M | Y: PhysicalChannel with MC multiplexing |
| Master Channel | clause 3.2.2 | M | Y: MasterChannel with VC multiplexing |
| Virtual Channel | clause 3.2.3 | M | Y: VirtualChannel with frame buffering |
| Frame Gap Detection | clause 3.3 | M | Y: Per-VC 24-bit count tracking |
| VC Multiplexing | clause 3.3.2 | M | Y: Weighted round-robin via SDL |
| MC Multiplexing | clause 3.3.3 | M | Y: Weighted round-robin via SDL |
Legend: M = Mandatory, O = Optional, C = Conditional, Y = Yes (supported), N = No (not supported)
Wire test vectors
The octets backing this statement live in the vector corpus — 12 vectors. Each vector names the clause it comes from and carries the derivation that produced it.
| File | |
|---|---|
aos/frame.json | 10 vectors |
aos/mpdu.json | 2 vectors |
These are data files, so any implementation can check itself against the same octets. See CONTRACT.md for how, and how this is verified for what rests on a published vector versus a reading of the clause.