# Time of arrival: three tripwire sensors, and the event that made them fire.
#
# Seven entities:
#   example.toa.wire.a    a tripwire sensor
#   example.toa.wire.b    a tripwire sensor, 202 m east of A
#   example.toa.wire.c    a tripwire sensor, 195 m north of A
#   example.toa.det.b     B heard something first, at 09:14:02.386
#   example.toa.det.a     A heard it 114 ms later, at 09:14:02.500
#   example.toa.det.c     C heard it last, at 09:14:02.816
#   example.toa.track.1   where the sound came from
#
# The event is south of all three sensors, outside the triangle they form.
# Nothing in the input says that. It comes only from the order of the three
# arrival times, and from the gaps between them.
#
# One tripwire cannot say where a sound came from. It says only that a sound
# reached it, and when. Sound travels 343 m each second, so the difference
# between two arrival times is a difference in distance. Three sensors give
# two independent differences, which is enough for a position in two
# dimensions. The fusion engine solves for the position and the moment of the
# event together.
#
# The measurement is the timestamp. Each sensor puts its arrival time in
# `lifetime.fresh`, which is the field for when an observation happened.
#
# push it with:  hydris ec apply time-of-arrival.yaml

---
# Sensor A.
id: example.toa.wire.a
label: Tripwire A

geo:
  latitude: 54.1800
  longitude: 12.0860
  altitude: 4

device:
  class: tripwire
  category: Ground
  state: DeviceStateActive
  unique_hardware_id: a84041c6545d1401

link:
  status: LinkStatusConnected
  rssi_dbm: -88

power:
  battery_charge_remaining: 0.76
  voltage: 3.9

classification:
  taxonomy:
    - confidence:
        confidence: 1.0
      equipment:
        sensor:
          emplaced: {}
          acoustic: {}

symbol:
  milStd2525C: SFGPESE---

routing:
  channels:
    - {}

---
# Sensor B, 202 m east of A.
id: example.toa.wire.b
label: Tripwire B

geo:
  latitude: 54.1800
  longitude: 12.0891
  altitude: 4

device:
  class: tripwire
  category: Ground
  state: DeviceStateActive
  unique_hardware_id: a84041c6545d1402

link:
  status: LinkStatusConnected
  rssi_dbm: -91

power:
  battery_charge_remaining: 0.71
  voltage: 3.8

classification:
  taxonomy:
    - confidence:
        confidence: 1.0
      equipment:
        sensor:
          emplaced: {}
          acoustic: {}

symbol:
  milStd2525C: SFGPESE---

routing:
  channels:
    - {}

---
# Sensor C, 195 m north of A. Three sensors that are not in one line give a
# position. Three sensors in one line do not.
id: example.toa.wire.c
label: Tripwire C

geo:
  latitude: 54.1815
  longitude: 12.08755
  altitude: 4

device:
  class: tripwire
  category: Ground
  state: DeviceStateActive
  unique_hardware_id: a84041c6545d1403

link:
  status: LinkStatusConnected
  rssi_dbm: -84

power:
  battery_charge_remaining: 0.80
  voltage: 3.9

classification:
  taxonomy:
    - confidence:
        confidence: 1.0
      equipment:
        sensor:
          emplaced: {}
          acoustic: {}

symbol:
  milStd2525C: SFGPESE---

routing:
  channels:
    - {}

---
# What sensor A reported. The sound reached it 114 ms after B.
#
# The sensor knows the time, and nothing else. It cannot give a direction or a
# distance, so the detection sits on the sensor inside a large circle. Do not
# guess a position here. The circle is honest, and the fusion engine replaces
# it with a real one.
id: example.toa.det.a
label: Acoustic Trip A

controller:
  id: example.toa.wire.a

priority: PriorityImmediate

# the arrival time. this is the whole measurement
lifetime:
  fresh: "2026-03-01T09:14:02.500Z"

detection:
  detectorEntityId: example.toa.wire.a
  confidence: 0.6

pose:
  parent: example.toa.wire.a
  cartesian:
    covariance:
      mxx: 250000
      myy: 250000

routing:
  channels:
    - {}

---
# What sensor B reported. It is nearest to the event, so it heard the sound
# first.
id: example.toa.det.b
label: Acoustic Trip B

controller:
  id: example.toa.wire.b

priority: PriorityImmediate

lifetime:
  fresh: "2026-03-01T09:14:02.386Z"

detection:
  detectorEntityId: example.toa.wire.b
  confidence: 0.5

pose:
  parent: example.toa.wire.b
  cartesian:
    covariance:
      mxx: 250000
      myy: 250000

routing:
  channels:
    - {}

---
# What sensor C reported. It is the furthest away, so it heard the sound last,
# 430 ms after B. That large gap is what puts the event south of the others.
id: example.toa.det.c
label: Acoustic Trip C

controller:
  id: example.toa.wire.c

priority: PriorityImmediate

lifetime:
  fresh: "2026-03-01T09:14:02.816Z"

detection:
  detectorEntityId: example.toa.wire.c
  confidence: 0.7

pose:
  parent: example.toa.wire.c
  cartesian:
    covariance:
      mxx: 250000
      myy: 250000

routing:
  channels:
    - {}

---
# The fused result.
#
# The fusion engine reads the three arrival times, solves for the position and
# the moment of the event, and pushes this entity.
#
# The output is a track. A detection is what one sensor measured. A track is a
# located thing, and the rule is that simple: if you can say where it is, it
# is a track. Three tripwires that could each say only "something is near me"
# become one point that a person can act on.
#
# `track.evidence` names the three detections, so an operator can ask which
# sensors produced this point, and a later stage can use them again.
#
# `lifetime.fresh` holds the moment the fusion engine solved for. It is 386 ms
# before the first sensor heard anything, because the sound needed that long
# to travel 132 m.
#
# The covariance follows from the clock. These sensors share time over a radio
# to about 10 ms, and 10 ms of sound is 3.4 m. The result is 4.5 m of error
# east and 16.9 m north. The ellipse points north because the event lies south
# of all three sensors. All three measure the distance to the south in nearly
# the same direction, so nothing constrains it well. An event inside the
# triangle gives a round ellipse. Better clocks give a smaller one.
#
# There is no symbol here. The classification is still pending, so the engine
# derives a pending symbol from the taxonomy.
id: example.toa.track.1
label: TRK-0031

controller:
  id: example.fusion.toa

lifetime:
  fresh: "2026-03-01T09:14:02.000Z"

track:
  # which fusion engine produced this
  tracker: example.fusion.toa
  confidence: 0.83

  evidence:
    - example.toa.det.a
    - example.toa.det.b
    - example.toa.det.c

geo:
  latitude: 54.1790
  longitude: 12.0880
  altitude: 4
  # meters squared, local ENU frame. xx=east, yy=north, xy=correlation
  covariance:
    mxx: 20.1
    myy: 285.5
    mxy: -42.2

classification:
  taxonomy:
    - confidence:
        confidence: 0.5
        pending: true
      person: {}

routing:
  channels:
    - {}