{
  "_meta": {
    "__meta__": "synthetic",
    "disclaimer": "Synthetic demo data inspired by real Baltic geography, MMSI/OUI conventions, and infrastructure. Not real observations.",
    "dataset": "s1-ais-dark-near-cable/timeline",
    "version": "1.0",
    "anchor_ts": "2025-03-18T05:30:00Z",
    "window_open_ts": "2025-03-18T05:30:00Z",
    "window_close_ts": "2025-03-18T08:00:00Z"
  },
  "events": [
    {"ts_iso": "2025-03-18T05:00:00Z", "t_rel": "T-00:30:00", "event": "AAL enters 200 km detection plane SE of Finland; AIS nominal", "signals": ["ais"], "notes": "Context only — preceding the dense window."},
    {"ts_iso": "2025-03-18T05:30:00Z", "t_rel": "T+00:00:00", "event": "Dense capture window opens; AAL at 60.0500, 27.5500, SOG 12.4 kn, COG 268°", "signals": ["ais", "plane_radar"], "notes": "Plane radar RAD-PLN-01 confirms AIS within 150 m."},
    {"ts_iso": "2025-03-18T05:38:20Z", "t_rel": "T+00:08:20", "event": "AAL crosses notional FI EEZ line; navStatus = 0", "signals": ["ais"], "notes": ""},
    {"ts_iso": "2025-03-18T05:40:00Z", "t_rel": "T+00:10:00", "event": "Decoy MV VENLA RESEARCH (230888011) enters from W at 60.05, 23.10, doing 6.0 kn", "signals": ["ais"], "notes": "Legitimate parallel research transit."},
    {"ts_iso": "2025-03-18T05:44:10Z", "t_rel": "T+00:14:10", "event": "First MAC hit at MAC-KTK-COAST-01: crew MAC A4:83:E7:5C:9B:11 (P-AAL-MASTER), RSSI -82 dBm", "signals": ["mac"], "notes": "Matches 41 prior baseline sessions."},
    {"ts_iso": "2025-03-18T05:48:40Z", "t_rel": "T+00:18:40", "event": "MAC-KTK-COAST-01 RSSI peak -71 dBm", "signals": ["mac"], "notes": "Range-bearing reference."},
    {"ts_iso": "2025-03-18T05:54:00Z", "t_rel": "T+00:24:00", "event": "MAC-KTK-COAST-01 session ends (onlineDurationSeconds ≈ 590)", "signals": ["mac"], "notes": "sessionEnd populated."},
    {"ts_iso": "2025-03-18T06:03:50Z", "t_rel": "T+00:33:50", "event": "MAC-PRV-COAST-01 picks up crew MAC; RSSI -88 dBm climbing", "signals": ["mac"], "notes": ""},
    {"ts_iso": "2025-03-18T06:11:30Z", "t_rel": "T+00:41:30", "event": "MAC-PRV-COAST-01 RSSI peak -68 dBm; AIS nominal", "signals": ["mac", "ais"], "notes": "Both sources confirm trajectory."},
    {"ts_iso": "2025-03-18T06:15:00Z", "t_rel": "T+00:45:00", "event": "VENLA begins survey loiter inside 800 m of Estlink alignment (1.5–3 kn)", "signals": ["ais"], "notes": "Decoy false-positive trap begins."},
    {"ts_iso": "2025-03-18T06:18:00Z", "t_rel": "T+00:48:00", "event": "AAL 6 NM east of Estlink 500 m buffer east edge", "signals": ["ais", "plane_radar"], "notes": "Pre-event flag."},
    {"ts_iso": "2025-03-18T06:25:10Z", "t_rel": "T+00:55:10", "event": "AIS goes silent — last position 60.1800, 25.1800, SOG 12.0 kn", "signals": ["ais"], "notes": "AIS gap STARTS. No 'AIS off' flag — just stop."},
    {"ts_iso": "2025-03-18T06:27:00Z", "t_rel": "T+00:57:00", "event": "Plane radar RAD-PLN-01 still holds track; SOG 12.0→10.6 kn, COG 268°→256°", "signals": ["plane_radar"], "notes": "Independent confirmation through the AIS dark."},
    {"ts_iso": "2025-03-18T06:32:40Z", "t_rel": "T+01:02:40", "event": "MAC-PRV-COAST-01 detects burner 7E:2A:F1:09:44:C8; RSSI -97 dBm; manufacturer = null", "signals": ["mac"], "notes": "LAA bit set on first octet."},
    {"ts_iso": "2025-03-18T06:38:00Z", "t_rel": "T+01:08:00", "event": "AAL enters Estlink-1 500 m buffer polygon (radar-only)", "signals": ["plane_radar"], "notes": "Spatial highlight."},
    {"ts_iso": "2025-03-18T06:42:20Z", "t_rel": "T+01:12:20", "event": "Burner RSSI peaks -79 dBm at MAC-PRV-COAST-01, then fades", "signals": ["mac"], "notes": "Active only during slow pass."},
    {"ts_iso": "2025-03-18T06:48:00Z", "t_rel": "T+01:18:00", "event": "Plane-radar SOG dips to 8.4 kn (loiter) over Estlink alignment", "signals": ["plane_radar"], "notes": "Composite incident score spikes here."},
    {"ts_iso": "2025-03-18T06:51:30Z", "t_rel": "T+01:21:30", "event": "Drone overflight RAD-DRN-PAT-01 confirms hull, no AIS Tx", "signals": ["drone_radar"], "notes": "Optional asset (not generated in this build)."},
    {"ts_iso": "2025-03-18T06:54:10Z", "t_rel": "T+01:24:10", "event": "Burner MAC last seen at MAC-PRV-COAST-01; RSSI -101 dBm", "signals": ["mac"], "notes": "Session ~22 min total."},
    {"ts_iso": "2025-03-18T06:58:00Z", "t_rel": "T+01:28:00", "event": "AAL exits Estlink-2 500 m buffer west edge (radar-only)", "signals": ["plane_radar"], "notes": ""},
    {"ts_iso": "2025-03-18T06:58:30Z", "t_rel": "T+01:28:30", "event": "AIS reappears at 60.2100, 24.6200, SOG 10.2 kn, COG 256°", "signals": ["ais"], "notes": "33 m 20 s gap; ~14.1 NM displacement; 12° course change."},
    {"ts_iso": "2025-03-18T07:05:00Z", "t_rel": "T+01:35:00", "event": "MAC-HEL-COAST-01 picks up crew MAC; RSSI -94 dBm", "signals": ["mac"], "notes": "Crew MAC re-attaches normally."},
    {"ts_iso": "2025-03-18T07:16:00Z", "t_rel": "T+01:46:00", "event": "MAC-HEL-COAST-01 RSSI peak -73 dBm", "signals": ["mac"], "notes": ""},
    {"ts_iso": "2025-03-18T07:35:00Z", "t_rel": "T+02:05:00", "event": "AAL south of Inkoo, SOG back to 12.0 kn, COG 264°", "signals": ["ais", "plane_radar"], "notes": "Persistent ~4° course offset vs original plan."},
    {"ts_iso": "2025-03-18T07:50:00Z", "t_rel": "T+02:20:00", "event": "MAC-HKO-COAST-01 picks up crew MAC; RSSI -90 dBm", "signals": ["mac"], "notes": ""},
    {"ts_iso": "2025-03-18T08:00:00Z", "t_rel": "T+02:30:00", "event": "Dense window closes; AAL on Hanko approach", "signals": ["ais", "plane_radar", "mac"], "notes": "End of demo loop."}
  ]
}