| --- |
| language: |
| - en |
| license: other |
| tags: |
| - nemo |
| - parakeet |
| - whisper |
| - qwen3 |
| - ctranslate2 |
| - automatic-speech-recognition |
| - text-generation |
| - air-traffic-control |
| - atc |
| - singapore |
| - military |
| pipeline_tag: automatic-speech-recognition |
| --- |
| |
| # ASTRA ATC Models |
|
|
| Fine-tuned models for Singapore military air traffic control, built for the [ASTRA](https://github.com/aether-raid) training simulator. |
|
|
| ## Pipeline |
|
|
| ```text |
| Audio --> VAD (Silero) --> ASR (Whisper or Parakeet) --> Rule Formatter --> Display Text |
| "camel climb flight level zero nine zero" |
| "CAMEL climb FL090" |
| ``` |
|
|
| The production pipeline uses a deterministic rule-based formatter instead of the legacy LLM formatter. |
|
|
| ## Models |
|
|
| ### [ASR/whisper/](./ASR/whisper) - Whisper Large v3 (Legacy CTranslate2 backend) |
|
|
| Fine-tuned for Singapore military ATC speech. Uses CTranslate2 float16 format for fast inference with [faster-whisper](https://github.com/SYSTRAN/faster-whisper). |
|
|
| | Metric | Value | |
| |--------|-------| |
| | WER | **0.66%** | |
| | Base model | `openai/whisper-large-v3` | |
| | Size | 2.9 GB | |
| | Runtime | `faster-whisper` / CTranslate2 | |
|
|
| ### [ASR/parakeet/](./ASR/parakeet) - Parakeet-TDT 0.6B v2 (NeMo checkpoint) |
|
|
| Fine-tuned NeMo Parakeet model for Singapore military ATC speech. Published as a raw checkpoint together with the tokenizer artifacts required to restore it. |
|
|
| | Metric | Value | |
| |--------|-------| |
| | Validation WER | **0.72%** | |
| | Base model | `nvidia/parakeet-tdt-0.6b-v2` | |
| | Size | 7.0 GB | |
| | Runtime | `nemo_toolkit[asr]` | |
|
|
| ### [LLM/](./LLM) - Qwen3-1.7B Display Formatter (Legacy) |
|
|
| > **Legacy.** Superseded by the deterministic rule formatter. Retained for reference only. |
|
|
| Converts normalized ASR output into structured ATC display text. |
|
|
| | Metric | Value | |
| |--------|-------| |
| | Exact match | **100%** (161/161) | |
| | Base model | `unsloth/Qwen3-1.7B` | |
| | Size | 3.3 GB | |
|
|
| ## Architecture |
|
|
| ```text |
| Audio --> VAD (Silero) --> ASR backend --> Post-processing --> Rule Formatter --> Display Text |
| ``` |
|
|
| | Component | Technology | Notes | |
| |-----------|------------|-------| |
| | VAD | Silero VAD | Shared frontend for both ASR backends | |
| | ASR (legacy) | Whisper Large v3 (CTranslate2) | Lower-memory legacy backend | |
| | ASR (current NeMo path) | Parakeet-TDT 0.6B v2 | Fine-tuned NeMo checkpoint | |
| | Formatter | Deterministic rules | Converts normalized speech to ATC display text | |
|
|
| ## Domain |
|
|
| Singapore military ATC covering Tengah and Paya Lebar operations, military phraseology, 100+ callsigns, and approach / recovery / emergency traffic. |
|
|
| ## Training History |
|
|
| ### ASR |
|
|
| | Run | WER | Base | Key Change | |
| |-----|-----|------|------------| |
| | ct2_run5 | 0.48% | jacktol/whisper-large-v3-finetuned-for-ATC | Initial fine-tune | |
| | ct2_run6 | 0.40% | jacktol/whisper-large-v3-finetuned-for-ATC | +augmentation, weight decay | |
| | ct2_run7 | 0.24% | jacktol/whisper-large-v3-finetuned-for-ATC | Frozen encoder, +50 real recordings | |
| | ct2_run8 | 0.66% | openai/whisper-large-v3 | Full retrain from base, enhanced augmentation | |
| | parakeet_atc | 0.72% | nvidia/parakeet-tdt-0.6b-v2 | NeMo fine-tune with ATC radio augmentation, best checkpoint at epoch 76 | |
| |
| ### LLM |
| |
| | Run | Accuracy | Key Change | |
| |-----|----------|------------| |
| | llm_run3 | 98.1% (Qwen3-8B) | QLoRA 4-bit, 871 examples | |
| | llm_run4 | 100% (Qwen3-1.7B) | bf16 LoRA, 1,915 examples with ASR noise augmentation | |
| |
| ## Quick Start |
| |
| ### Whisper ASR |
| |
| ```python |
| from faster_whisper import WhisperModel |
|
|
| model = WhisperModel("./ASR/whisper", device="cuda", compute_type="float16") |
| segments, info = model.transcribe("audio.wav", language="en", beam_size=5) |
| text = " ".join(seg.text.strip() for seg in segments) |
| ``` |
| |
| ### Parakeet ASR |
| |
| See [ASR/parakeet/README.md](./ASR/parakeet/README.md) for the NeMo restore example and tokenizer artifact requirements. |
| |
| ## Download |
| |
| ```bash |
| # Full repo |
| huggingface-cli download aether-raid/astra-atc-models --local-dir ./models |
|
|
| # Whisper ASR only |
| huggingface-cli download aether-raid/astra-atc-models --include "ASR/whisper/*" --local-dir ./models |
| |
| # Parakeet ASR only |
| huggingface-cli download aether-raid/astra-atc-models --include "ASR/parakeet/*" --local-dir ./models |
|
|
| # LLM only (legacy) |
| huggingface-cli download aether-raid/astra-atc-models --include "LLM/*" --local-dir ./models |
| ``` |
| |
