Maritime VHF monitor · a Bifrost Thorware product
Every marine channel. At once. In English.
Bifrost watches the entire marine VHF band simultaneously — not one channel at a time — transcribes every transmission, translates it into English, and decodes AIS and DSC from the same receiver. It runs on one commodity computer at the edge, with no internet connection in the processing path.
In plain terms: it listens to the whole marine radio band at the same time, writes down everything that is said, translates it into English, and keeps a searchable record with the audio — all on one computer, with nothing sent to the internet.
One receiver, three jobs
A single wideband tune covers 155.80 – 162.20 MHz. Everything below comes out of that one stream, on one machine.
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Watch the whole band
That 6.4 MHz of spectrum is split into 256 slots of 25 kHz — the ITU maritime channel spacing — and all 256 are demodulated continuously and in parallel. 92 of those slots carry a defined ITU marine channel, 57 ship side and 35 coast side, and those are the 92 the station watches. Every channel is judged against its own noise floor, so a quiet channel is never missed while a loud one is busy. Nothing is scanned.
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Transcribe and translate locally
Every transmission becomes a record with audio, timing, channel and signal strength — an "over" in radio terms, from the moment the channel opens to the moment it closes. Speech is transcribed and translated into English on the station itself. 49 languages have been observed in real traffic; the model carries 100.
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Decode the data channels
Both AIS channels and DSC channel 70 are decoded from the same front end, with error-check validation on DSC. Vessel identity, position, course and destination land on an offline chart beside the voice traffic.
Built for
Four operating pictures, one box. Each of these is a watch that is currently kept by one person with one radio, or not kept at all.
Unmanned surface vessel operators
Over-the-horizon ears: what was said on the water, in English, without a crew. A USV cannot hear or answer VHF, and COLREG compliance and water-space deconfliction both depend on it. That is a collision-avoidance problem before it is an intelligence one.
Ports and pilotage authorities
Every channel logged, searchable, with audio retained for incident reconstruction. Port control hears what it has selected; nothing is kept and nothing is searchable.
Navies and coalition exercises
A complete multilingual record of exercise water space, produced on the exercise LAN. No cloud service is acceptable on that network, and no watch floor staffs 48 languages.
Survey and offshore operators
Awareness of diving, towing and restricted-manoeuvre traffic around the work site — currently a radio watch kept by one person who may be doing something else.
Measured, not claimed
Every figure below was read from a running station or computed from its stored corpus: 7,607 logged transmissions across two sites, 8 August – 29 September 2026. That window is 53 calendar days, of which 26 carried logged traffic — 5 on the California bench in August and 21 on deployment in Portugal in September. Nothing was logged between those two periods. Availability across the window is not instrumented, so every count here is stated against days with logged traffic rather than calendar days.
Receiver reliability is the strongest result in the record: a software-defined receiver that processed over 432 billion samples without losing one, without a single stream overflow and without a single restart.
The console
The operator interface is an ordinary web browser — no client install. Updates are pushed to the page, so nothing polls and nothing goes stale.
Tested at REPMUS 26 for 21 days
Bifrost ran for twenty-one days against live coalition and commercial traffic in the Sesimbra and Setúbal approaches during REPMUS 26, the NATO and Portuguese Navy robotic experimentation exercise. The station was set up on 8 September and ran until 29 September.
Said plainly: this was taken on as extra credit. Bifrost Thorware LLC was not an invited participant, held no exercise serial and received no funding for it. The station was carried in the margins of an unmanned surface vessel deployment, on one small computer, and it does not appear in the REPMUS 26 after-action report. Its data is nonetheless the only recorded radio-frequency picture of that water space anyone holds.
“Sécurité, Sécurité, Sécurité, all stations, all stations, all stations. This is RIB Laguna, Laguna, Laguna. Underwater drone operations completing 100 metres south-west of my location, 38 degrees north, 25.370, 9 degrees west, 7.169. Unmanned vehicles surfacing shortly.”
Captured verbatim, with spoken position, 15 September 2026 at 09:09 UTC. One of roughly 22 navigational-safety broadcasts recorded in full during the exercise.
“Atenção a todas as estações, daqui DMS2, mergulho, mergulho, mergulho, Yankee, Charlie 1.”
→ “Attention all stations, from here DMS2, dive, dive, dive, Yankee Charlie 1.”
Divers entering the water, announced to all stations on channel 9 — captured, transcribed and translated unattended at 11:42 UTC on 29 September 2026, while the station was being assessed.
| Days with logged traffic | 21 |
|---|---|
| Transmissions logged | 7,115 |
| Transcribed · translated to English | 4,095 · 2,788 |
| Languages observed | 48 |
| Marine channels carrying speech | 33 |
| AIS vessels · messages | 561 · 865,492 |
| DSC calls decoded | 24, of which 22 passed the error check |
| Also captured | A French warship anchoring notification on channel 16, in French · an orca attack reported by a sailing vessel 4 nm south of Sesimbra · five diving-operations broadcasts |
What it heard, by language
49 languages appeared in real traffic over the corpus. The ten most common:
- English 1,367
- Portuguese 1,234
- German 379
- Russian 347
- Spanish 184
- Italian 146
- French 68
- Polish 63
- Greek 58
- Dutch 55
- + 39 more
Specification
What the station does and what it needs. Implementation detail is covered under NDA.
| Band covered | 155.80 – 162.20 MHz, marine VHF |
|---|---|
| Coverage method | Whole band at once — no scanning, no channel selection |
| Channels watched | 256 at 25 kHz · 92 ITU maritime channels |
| Per-channel detection | Independent squelch against each channel's own noise floor |
| Concurrent voice traffic | Multiple channels captured simultaneously |
| AIS | Both channels, same receiver, no extra hardware |
| DSC | Channel 70, error-check validated |
| Antenna | Standard marine VHF antenna |
| Compute | One commodity computer — no rack, no GPU server |
|---|---|
| Speech and translation | Run on the station · to English · 100 languages |
| Network dependency | None in the processing path |
| Audio retained | Every transmission, playable in the log |
| Time-shifted listening | Five-minute rolling buffer per channel, jump to live |
| Search | Full text across every transcript and translation |
| Export | ZIP of CSV, JSON and audio — 24 h in under 2 s |
| Operator interface | Web browser, pushed updates, no install |
| Deployment | Vessel, shore station or USV |
| Measured draw, running | 11 – 20 W |
|---|---|
| Supply | Vessel DC bus, battery, or shore / generator AC |
11 – 20 W is a measured draw at the wall for the whole station, receiving and transcribing. A detailed breakdown by state — idle, peak, and inrush — has not been instrumented yet and is not quoted here.
Where it is, and where it is not
Bifrost is offered as a monitoring, recording and analysis tool. We publish what has been measured and name what has not, because a technical evaluator will ask.
What the evidence supports today
- The radio is production-grade. Zero lost samples across 432 billion, zero overflows, zero restarts.
- Roughly seven transcripts in ten are operationally useful — graded good or partial by blind scoring of a 240-transmission sample, corroborated by a separate 533-sample audit.
- Long, well-formed safety broadcasts are captured in full, including spoken positions, verbatim and unattended.
- AIS and DSC decoding are strong, with error-check validation on every DSC call.
What we do not claim
- Not a safety-of-life alerting product. Keyword alerting on distress traffic is not reliable yet and is not offered. Improving the language layer for maritime speech is the specific focus of current work.
- No word error rate is published, because none has been measured on this system.
- No maritime-adapted speech model yet. The model is general purpose.
- Availability, end-to-end latency and receiver sensitivity are not yet instrumented. They are on the roadmap and will be published when measured.
Pilot deployments
Bifrost is available for pilot deployment now. Contact us for pricing.
What a pilot looks like
- One station, one site. A shore station, a vessel or a USV, with a standard marine VHF antenna.
- It runs on your network. The operator interface is a web browser on the local network. Nothing leaves the station.
- You keep the record. Every transmission, transcript, translation and the audio behind it, exportable as CSV, JSON and WAV.
- We publish what it did. The same measured figures you see on this page, for your water space.
Read this before you ask
- This is a development build and it is not accredited. Output is for exercise, training, development and evaluation use, not for real-world operations, until a military organisation has evaluated and accredited it.
- It is receive-only. It does not transmit. It is not a substitute for a licensed VHF radio watch or for GMDSS equipment.
- Distress keyword alerting is disabled and stays disabled until its false-positive rate is measured and closed.
- It has no access control yet. Run it on a trusted network only, pending the authentication release.
Get in touch
Bifrost is built by Bifrost Thorware LLC in Jacksonville, Florida, alongside CTRL ALT MINE DEL, an APP-11(E) OPREP NMW message builder, and BATHY CONVERTER, a marine bathymetry file converter. For a briefing, a demonstration or a pilot, contact murphy@bifrostthorware.com.
murphy@bifrostthorware.com