# Virtual drone fleet

A data generator that exercises the **exact on-board pipeline** described in [03 — Data platform](../docs/03-data-platform.md): seeded kinematics along a patrol route, sensor streams at realistic rates, detection events, the hot `current/` → sealed Parquet write path, and the compact UDP state broadcast between drones.

One process = one drone. Scaling the swarm is a Compose flag.

## Run a swarm

```bash
# 5 drones (default), 2-minute flight, shared flight id
FLIGHT_ID=$(date -u +%Y%m%dT%H%MZ)-sim docker compose up --build --scale drone=5

# 10 drones, 5-minute flight, 4x accelerated
DRONE_COUNT=10 DURATION_S=300 SPEEDUP=4 docker compose up --build --scale drone=10
```

Output lands in `./data/` with the standard layout:

```
data/dataset=telemetry/flight=…/drone=…/sensor=imu/year=…/…/hour=…/data.parquet
data/dataset=detections/flight=…/drone=…/…
data/dataset=state/flight=…/drone=…/…        ← sent + received broadcasts
```

## Run a single drone without Docker

```bash
pip install -r requirements.txt
DRONE_ID=dr-01 DURATION_S=30 SPEEDUP=10 DATA_DIR=./data python -m virtual_drone.main
```

## Query the results

```bash
python - <<'EOF'
import duckdb
con = duckdb.connect()
print(con.sql("""
    SELECT drone, sensor, count(*) AS rows,
           to_timestamp(min(ts_ns)/1e9) AS first_row,
           to_timestamp(max(ts_ns)/1e9) AS last_row
    FROM read_parquet('data/dataset=telemetry/**/*.parquet', hive_partitioning=true)
    GROUP BY drone, sensor ORDER BY drone, sensor
"""))
print(con.sql("""
    SELECT drone, direction, count(*) AS frames, count(DISTINCT peer_id) AS peers
    FROM read_parquet('data/dataset=state/**/*.parquet', hive_partitioning=true)
    GROUP BY drone, direction ORDER BY drone, direction
"""))
EOF
```

## Reproducibility

Every run is deterministic per `(SEED, DRONE_ID)`: same route jitter, same sensor noise, same detection sequence. A bug report is a seed and a config, not a description.

## Knobs

| Env | Default | Meaning |
| --- | --- | --- |
| `DRONE_ID` | derived from hostname | Unique per container automatically under `--scale` |
| `FLIGHT_ID` | generated | Set explicitly so all drones share one flight partition |
| `SEED` | `42` | Determinism root |
| `DURATION_S` | `120` | Simulated flight length |
| `SPEEDUP` | `1.0` | Wall-clock acceleration |
| `IMU_HZ` | `50` | High-rate sensor load |
| `STATE_HZ` | `5` | Broadcast frequency |
| `AREA_SIZE_M` | `400` | Patrol square side |