Crate kinavis_ais 

AIS messages from their NMEA sentences to the KINAVIS types.

A receiver delivers an AIS message as one or more !AIVDM sentences, 6 bits per character. kinavis-nmea0183 validates each sentence and yields a Vdm with the payload still armoured; this crate:

1. Unarmours the payload into Bits, a fixed-capacity buffer read by bit offset and width as in the standard’s tables.
2. Reassembles multi-sentence messages in an Assembler with fixed slots and a timeout, so a lost fragment costs one message, not a slot.
3. Decodes into a Message with kernel field types: Position, Speed, TrueCourse, TargetId for the MMSI, Distance for draught, InlineStr for names. “Not available” is None, never a zero or a string of @.

No allocation, no panics on any input; builds for bare-metal targets and CI checks the strict-profile build for panic paths.

use kinavis_ais::{Assembler, Message};
use kinavis_kernel::{Instant, Utc};
use kinavis_nmea0183::{parse, Sentence};

let mut assembler = Assembler::new();
let now = Instant::<Utc>::from_unix_seconds(1_789_000_000);

let line = b"!AIVDM,1,1,,A,13aEOK?P00PD2wVMdLDRhgvL289?,0*26\r\n";
let Sentence::Vdm(vdm) = parse(line)? else { panic!("not an AIS sentence") };
let Some(bits) = assembler.push(&vdm, now)? else { panic!("in fragments") };
let Message::PositionReport(report) = Message::decode(&bits)? else { panic!("not a position") };

assert_eq!(report.mmsi.number(), 244_670_316);
assert_eq!(format!("{:.3}", report.position.unwrap()), "51°53.685'N 004°22.757'E");
assert_eq!(report.course.map(|c| c.degrees()), Some(70.6));
assert_eq!(report.speed.map(|s| s.knots()), Some(0.0));
assert_eq!(report.heading, None, "not available, not north");

The caller builds the TargetObservation for the traffic picture from these fields; this crate depends only on the kernel and the sentence crate.

Supported messages

Message	Decoded as
1, 2, 3 — class A position report	PositionReport
5 — class A static and voyage data	StaticAndVoyageData
18 — class B position report	PositionReport
19 — class B extended position report	PositionReport, with name, type and dimensions
21 — aid to navigation	AidToNavigation
24 — class B static data report, part A or B	StaticDataReport

Other well-formed messages decode as Message::Unsupported with the message type and the raw Bits.

Feature flags

• std (default) — standard library maths in the kernel.
• libm — for no_std targets: --no-default-features --features libm.
• serde — serialisation of the messages.

Structs

AidToNavigation

Aid-to-navigation report.

Assembler

Fragment assembler with N slots.

Bits

Message bits in a fixed-capacity buffer.

ClassBStaticData

Class B static data, part B.

Dimensions

Dimensions from the reported position to bow, stern, port and starboard.

Eta

ETA, UTC, as far as given.

InlineStr

Short inline string.

PositionReport

Position report.

ShipType

Ship and cargo type, as the standard’s two-digit code.

StaticAndVoyageData

Class A static and voyage data: message 5.

StaticDataReport

Class B static data report: message 24, sent as two parts.

Vdm

AIS message or one fragment of it.

Enums

AidType

Aid-to-navigation type.

AisError

Why a payload could not be unarmoured, reassembled or decoded.

Channel

AIS radio channel.

HazardCategory

Cargo hazard category (A most hazardous, D least).

Mark

IALA mark type of a beacon or buoy.

Message

Decoded AIS message.

NavigationStatus

Class A navigational status.

PositionFixingDevice

Position fixing device type.

Quadrant

Cardinal quadrant: the side of the danger where safe water lies.

ShipCategory

Ship categories.

StaticDataPart

Parts of a class B static data report.

StationClass

Station class.

Turn

Class A rate of turn.

Constants

DEFAULT_TIMEOUT

Default timeout for an incomplete message.

MAX_ASSEMBLIES

Default number of concurrent assemblies.

MAX_MESSAGE_BITS

Maximum message length in bits.