Vehicle parts and their logs

A reconstruction is only as complete as the logs behind each part of the vehicle. Foxborne draws that coverage for every vehicle. It appears as Where each source is recorded on the vehicle page and as On the vehicle on an incident's Reconstruction tab.

This page lists the parts of both platform models in the example dataset, their wiring and the meaning of each tag.

How a part reaches the evidence#

Every part on the diagram falls into one of three cases, and its tag says which.

On an incident, the diagram knows which sources the run holds and what the evidence shows, so three more tags can appear.

How the diagram is drawn#

The platform sits in the middle as a line drawing. Each part gets a callout box on a leader line, which ends in a small square at the part's place on the drawing. Those placements are illustrative: plausible on the drawing, not measured from a real vehicle.

Each box gives the part's name, a short specification and its tag. The box shortens the companion's specification to fit, so AGX Orin 64 GB stands for Jetson AGX Orin 64 GB, Ubuntu 22.04.

The specification comes from the platform definition and names the model's PX4 version. The vehicle page's summary strip gives each vehicle's own version.

Range control is not part of the vehicle. The diagram adds it to the right of the drawing, as a Ground station recorded by the ground receive log. A dashed line joins it to the radio.

Wiring between parts is drawn as dotted lines, straight from part to part over the drawing.

T4 tracked UGV#

Route clearance and breaching support. Skid-steer tracks, PX4 rover (differential). The example fleet has six, UGV-01 to UGV-06, all on PX4 v1.16.0 except UGV-06 on v1.15.4. The diagram draws the T4 from above, front to the right.

Above the drawing the boxes read GNSS receiver, Mesh radio and Lidar. Below it they read Battery, Companion computer and Flight controller.

Because the T4's radio sits on USB, the companion's kernel logs it leaving and returning. In INC-0143 the radio sat on USB port 1-2.3 as the cdc_ether interface usb0. Device disconnect reads those kernel lines, and the example configuration scopes it to T4 vehicles.

The lidar reaches Foxborne only through what the companion's journal says about it. The collector reads only the units on its Journal units allowlist and ignores the rest of the journal on the vehicle. Keep the unit that logs the lidar on that list, as Set the collector policy describes.

Q4 recon quad#

Route reconnaissance. Quadcopter, PX4 multicopter. The example fleet has ten, UAS-01 to UAS-10, all on PX4 v1.15.4 except UAS-05 on v1.15.2. The diagram draws the Q4 from its right side, front to the right.

Above the drawing the boxes read Mesh radio, GNSS receiver and Depth camera. Below it they read Companion computer, Battery and Flight controller.

The depth camera plugs into the companion computer, yet its data lands in the flight log. In the example dataset, perception_node on the companion streams MAVLink OBSTACLE_DISTANCE at 10 Hz to the flight controller, and PX4 logs each message as obstacle_distance. A stall in that topic is what Topic stall caught in INC-0142 and INC-0139.

The companion's journal names two of these links. In INC-0142, when mavlink-router.service came back, mavlink-routerd logged Opened UART [1]fc: /dev/ttyTHS1 baud=921600 for the flight controller. It then logged Opened UDP Client [5]mesh: 10.20.0.2:14550 for the radio.

Parts that keep no log#

The mesh radio writes nothing Foxborne can read, on either platform. The event page's Radio card says so. Its Log line reads Keeps no log Foxborne can read, and Seen through reads Companion journal and the ground receive log.

Those two sources are the radio's neighbors. The companion's kernel sees its link come and go, and range control's receiver sees telemetry arrive or stop. What the radio itself did between the two is a gap, and the diagram marks it rather than filling it.

INC-0143: the radio that dropped off USB#

In INC-0143 of the example dataset, UGV-02 held mid-lane after its radio dropped off the USB bus. Everything known about the radio comes from its neighbors:

Range control received nothing for 31.0 s, from 15:41:02.713 to 15:41:33.689. PX4 held 11.88 s after the last ground heartbeat reached it at 15:41:02.412. None of those records is the radio's own, and the report's limitations say what that leaves open:

The report therefore writes vibration unseating the connector as a hypothesis until the connector is inspected. On the diagram, the radio reads State not observed from the disconnect at 15:41:02.604 until usb0 registers again at 15:41:32.214.

A part that keeps no log is where a reconstruction stops being direct. Every statement about it is inferred from its neighbors, and the evidence level says so. If such a part matters to your reviews, give it a record Foxborne reads, such as journal lines from an allowlisted unit on the companion.

How an incident numbers evidence on the parts#

On the Reconstruction tab, the diagram appears as On the vehicle, subtitled Where each event happened. Numbers follow the report.

• Badges are evidence references. Each numbered badge is an event in the report's sequence, numbered in the report's order: badge 6 is E6.
• A badge marks where the event happened. That is not always the part whose log recorded it. The kernel on the companion logged INC-0143's USB disconnect, and badge 2 sits on the mesh radio.
• Not every event gets a badge. A sequence event that the incident ties to no part has none.
• Badges select. Selecting a badge selects its event. The selected event's badge, box and leader line are highlighted.
• Links follow the cursor. The cursor is the time under the pointer on the timeline, else the selected event, else the incident's first finding. A link turns amber once the evidence shows it down and returns once the evidence shows it recovered. Events on a companion clock that is not aligned never move a link.

INC-0143 on UGV-02 carries this sequence:

At badge 2 the wire from the companion computer to the radio turns amber and the radio reads State not observed. At badge 4 the dashed line to range control turns amber and Range control reads Nothing received. At badge 7 the radio's wire returns and its tag reads Keeps no log again.

Badges also land on parts that keep no log of their own. INC-0141 on UAS-10 imported the flight log only, so the companion computer reads Journal not imported and Range control reads Receive log not imported.

Its GNSS receiver still carries two badges, both read from sensor_gps in the flight log. Badge 2 is Receiver reports jamming_state 3 (detected), and badge 5 is sensor_gps: 15 satellites, eph 0.9 m, jamming_state 1.

INC-0142 on UAS-04 puts badges 1, 3, 5 and 7 on the companion computer. Badge 2 sits on the flight controller and badge 6 on Range control.

Drawing credits#

The drawings are line renders of openly licensed 3D models, and the console keeps a credit for each one with the drawings. The two the diagram uses are credited as follows.

Foxborne rendered both as hidden-line drawings from the unmodified model geometry. The drawings show the platform type, not the example vehicles.

Related#