jvde-github/AIS-catcher v0.67 on GitHub

Version 0.67

New Features

HydraSDR Support

HydraSDR is now a supported input device. See the HydraSDR input page for details.

Duplicate Removal

When combining multiple input streams, overlapping reception can result in duplicate messages. To remove duplicates from output channels, use the unique option. For example, the following removes duplicates from both console and a UDP stream:

AIS-catcher -o 1 unique on -u 127.0.0.1 5012 unique on

In JSON, set the unique key to true (remove duplicates) or false (default). Note that this could come at a performance cost that increases with the number of MMSIs so keep an eye on that.

Downsampling Options

Two additional options, position_interval and own_interval, downsample position messages and VDO messages by limiting each MMSI to at most one update per specified interval (in seconds). Both default to 0 or, equivalent, false (disabled).

Example:

AIS-catcher -u 127.0.0.1 5012 position_interval 30

Alternatively, these options are available in the Visual Web Control interface:

Thanks to user Manny for suggesting these options.

Note: These options are intended for users aggregating across multiple receivers to reduce bandwidth, and have not been optimized for large vessel counts.

Serial Device Improvements

init_seq now accepts multiple comma-separated commands
Fixed init_seq issues on macOS (and Windows buffer flushing during init)
Serial devices supporting AIS-catcher format can now relay warning, info, and error messages through the program
New flowcontrol option (hardware/software/none) and disable_xonoff switch
Serial port opened in non-blocking mode to avoid DTR hang on some adapters
New dump_file option to save raw serial bytes for debugging
DC16H frame format support

Zones

Support for tailoring routing of messages from receivers to output channels via zones in JSON configuration and Visual Web Control.

Channel Designation (AB/CD)

Channel designation is now configurable via JSON config and is shown in model startup output of the Visual Web Control.

Microsecond Timestamps

rxuxtime field added to JSON_FULL output, providing microsecond-resolution receive timestamps. NMEA 4.0 tag-block timestamps now use microseconds where available.

Reboot Watchdog

A systemd OnFailure watchdog can automatically reboot the host if AIS-catcher stops repeatedly. Configurable burst/interval parameters with a 5-minute grace period after toggling, controlled via the install script.

Output and Configuration

Receiver index is now included in output; -v applies to all receivers, -v+ to the last one only
webcontrol_http option for the webviewer
ssl_verify setting on HTTP outputs to disable TLS certificate verification when needed
NMEA 4.0 tag blocks now include the group ID only for multi-line sentences
Default repeat for message type 27 is now 3
Aliases: rssi/fo for signalpower/ppm; DESC for description
Internal settings unified to a key-based API with structured error reporting (SetKey); legacy aliases kept for backward compatibility
Community feed restricted to local SDR hardware only

Web Viewer

Vessel Tracks — Major Overhaul

Incremental (delta) loading: only new path points are fetched on each update
Tracks capped at 250 points per vessel, consistent between "Show Track" and "Show All Tracks"

Multi-Receiver View

A new view in the webviewer lets users see and switch between multiple receivers from a single interface.

Realtime and UI Improvements

Realtime NMEA tab now displays the shipname instead of just MMSI
Station name passed via plugins.js for immediate tab title display
Community feed gained a binary compact endpoint, sprite-sheet icons, and click-to-livemap
Dark info panel, darker hover background, fixed truncated SVG flags
Fixed RainViewer overlay (CORS and API path), MBTiles import, distance charts, "Show all tracks", strict-mode violations, missing planes sprite, ship-shape highlight stuck on hover
Shrunk favicon.ico from 97 KB to 15 KB
marked library now bundled (no CDN runtime dependency)

Bug Fixes

Signal level charts: fixed extreme values for UDP/TCP sources
Static data refreshed correctly when a ship comes back into scope
HTTP stats fixed under TLS

Performance

This release contains a substantial performance overhaul of the I/O hot path. Highlights:

NMEA parser: zero-alloc split, SWAR scanning, bulk 6-bit decode, line-aware start detection — ~64% fewer instructions
JSON parser: zero-copy tokenizer, hand-rolled number parsing, flat open-addressing hash table for key lookup, allocation-free steady-state parsing
JSON Writer: replaces legacy JSONBuilder and ad-hoc serializers with a std::string-backed writer; ~5–10% faster on -o 0/3/5/7
AIS::Message: SWAR getText/getUint, batched 6-bit payload decode (~7–10% faster on -o 5 / nmea_refresh)
Lock-free output: thread-local screen buffers, atomic ByteCounter, DB mutex released before downstream Send cascade (dual -N benchmark: 9.05s → 6.03s)
POSIX read() for stdin, single newline flush per message (replacing per-message fflush)

Stability and Networking

TCP: try all addrinfo entries, connect timeout for blocking mode, guard repeated stop requests
WebSocket/MQTT: handshake fixes, Windows socket check, max frame drop, PUBREL handling, buffer-growth fix
Logger: fixed circular buffer and mutex issues
GPS: fixed use-after-free and JSON memory issue, warn-once on bad data, scan limits
Postgres/N2K: traffic monitoring extended, empty AIS messages handled, filter shadow fixed (settings now apply to the active filter)
File input, hybrid config, NMEA RMC parsing, NMEA checksum in -o 6, timer handling for non-frontend models (NMEA, N2K, ADSB, Export)
Backup writer wrapped in try/catch with additional diagnostics
Compiler-warning cleanup across the tree; spellcheck CI added (typos)

Packaging

Debian packages now store HydraSDR and RTL-SDR libraries as DLLs in /usr/lib/AIS-catcher instead of statically linking
Switched to debhelper — dh_shlibdeps auto-resolves correct dependencies per distro/arch
Fixed several .deb packaging issues (libssl3/t64, ETXTBSY, empty Depends field)
Added CI install test covering the full platform matrix
New Ubuntu ARM64 and ARMhf packages; RPM packages added; Fedora dropped
Frontend libraries bundled via npm/Vite — no CDN dependencies at runtime. Webassets repo is archived
Modular CMake dependency management — individual scripts per library
Install script: parallelized builds, non-root install option, hardened reboot handling, removed Docker support for i386/armel