Glossary

The terms these docs and the Foxborne console use, from anchor to write-once, each defined in one or two sentences with a link to the page that explains it in full.

ReferenceMarkdown

Terms are in alphabetical order. Each one has a stable anchor you can link to, such as /reference/glossary#order-unknown.

Anchor: What places a source's clock on UTC: GPS time for the flight log, chrony for the companion journal, NTP for the ground receiver. A source without one stays on its own clock, and Foxborne makes no before or after claim between it and anchored sources.See Clocks, anchors and error bounds.
Audit chain: The link between audit log entries: each entry carries the hash of the one before it, so a missing or altered entry breaks the chain. Verify chain recomputes each hash from its entry and the hash before it.See Audit log.
Boot ID: The identifier of one boot of the companion computer: _BOOT_ID in the journal and boot_id in collector records. Process samples that share the journal's boot ID share its clock.See Collector JSONL records, Clocks, anchors and error bounds.
Bound (error bound): How far a source's time can be off once anchored, written ±N, such as ±40 ms for a GPS-anchored flight log. A receipt adds link latency on the early side only.See Clocks, anchors and error bounds.
Break-glass account: A local admin account for when the identity provider is down. It requires a hardware security key, and each break-glass sign-in is audited and raises an alert in your SIEM.See Single sign-on.
Case file: The incident's report exported on marked pages, as a PDF case file with CUI markings, hashed with a SHA-256 manifest. Another engineer can check every excerpt against the originals without access to your deployment.See Export a case file, Reports and case files.
chrony: The service that keeps the companion computer's clock on UTC. Foxborne trusts the journal's wall time only while chrony reports a synchronized source.See Clocks, anchors and error bounds.
Clock domain: A group of sources that share one clock, so their events are always in order against each other. The companion journal and process samples share one; the flight log and the ground receiver each have their own.See Alignment and event order.
Collector: The optional Foxborne service on a vehicle's companion computer. It reads allowlisted journal units and processes, spools offline, uploads over mutual TLS and never sends MAVLink to the flight controller.See The companion collector, Collector JSONL records.
Combined bound: The sum of two sources' bounds, plus link latency when one of them is a receipt. Two events closer than it cannot be put in order: the flight log's ±40 ms and the journal's ±6 ms combine to ±46 ms.See Alignment and event order.
Companion journal: The systemd journal of a vehicle's companion computer, exported with journalctl -o json or uploaded by the collector. Each entry carries wall time, monotonic time and the boot ID.See journalctl JSON exports.
Correlated: The evidence level for events that line up inside a known error bound. In INC-0142, the next heartbeat was due 0.76 s after the router stopped.See Evidence levels.
CUI: Controlled unclassified information. Under a CUI marking, reports and case files carry the banner on every page and the designation indicator on the first.See CUI marking, Markings and handling.
Designation indicator: The block on the first page of every report and case file that says who controls the CUI. It gives the controlling organization, the office, the CUI category, the dissemination control and a point of contact.See CUI marking.
Dismissal: Setting a finding aside, with a reason that is required. The raw evidence does not change, and the audit log keeps the dismissal and its reason.See Rules and findings.
Dropout: A gap that the flight log itself marks as dropped data. log_dropout flags dropouts of 50 ms or longer.See log_dropout, PX4 ULog.
Elapsed time only: The clock state of a run with no anchor to UTC, such as an indoor hover with no GPS fix. Times read from log start, and nothing on the run is shown as wall-clock time.See Clocks, anchors and error bounds.
Evidence inspector: The side panel on an incident's Reconstruction tab that opens when you select an event. It shows the event's time and bound, source file with its SHA-256, original record and order against nearby events.See Read the timeline, Inspect an event.
Evidence level: How directly the sources support a statement: observed, correlated, hypothesis or unknown. The console and reports draw each level with its own shape.See Evidence levels.
Excerpt: A source record quoted byte for byte in a report, with its file's SHA-256 and its location, such as a line or row.See Verify a report against the originals.
EXPT: The CUI registry's category marking for export-controlled information. Evidence marked EXPT opens only for users whose identity provider asserts US person status.See Export-controlled evidence.
Failsafe: PX4's automatic response to a failure condition, such as the action NAV_DLL_ACT selects once COM_DL_LOSS_T runs out. failsafe_entered reports each failsafe with its cause from failsafe_flags.See failsafe_entered, PX4 parameters Foxborne reads.
Finding: A rule's result: what it observed, with the rule ID, version and threshold that produced it and the events it read. A report's first section, also called Finding, is the engineer's own paragraph.See Rules and findings.
Flight log: The PX4 ULog (.ulg) from the flight controller's SD card. Its clock counts microseconds from boot, and GPS time in sensor_gps anchors it to UTC.See PX4 ULog.
Ground receive log: The record of MAVLink messages the receiver at range control heard, one receiver JSONL line per message. The receiver stamps each line on arrival with its own clock.See Receiver JSONL records.
HEARTBEAT: The MAVLink message with ID 0, which each system sends at a steady rate, 1 Hz on typical radio links. telemetry_gap flags more than 3 s between heartbeats at the ground receiver.See Receiver JSONL records, telemetry_gap.
Hypothesis: The evidence level for an explanation that still needs a check. A report's Next check names one test or measurement that would confirm or refute it.See Evidence levels.
Import job: The steps Foxborne ran on a run's files, with their timings: validate, hash, parse, align clocks and run the rules. The same files and parser versions give the same event IDs.See Check a run.
Incident: One failure under investigation, opened on a window of a run, with the evidence behind every claim and an account of what is still unknown.See Runs, vehicles and incidents.
Incident window: The stretch of a run an incident covers, such as 14:31:53 to 14:32:16 in INC-0142. Fit incident returns the timeline to it.See Work an incident.
Latency: The time a message takes from the vehicle to the ground receiver. Foxborne measures it per run and extends a receipt's bound toward earlier times only.See Receiver JSONL records, Clocks, anchors and error bounds.
Legal hold: A hold that keeps a run from deletion, whatever the retention policy. Shortening retention does not delete anything on hold.See Retention, holds and redaction.
Lost-data marker: The marker the collector writes where it dropped samples after its spool budget filled, so the gap shows on the timeline instead of passing unnoticed.See Set the collector policy.
Manual alignment: An offset an engineer applies to an unaligned companion clock, from two events that happened at the same moment on both clocks. It carries its own, wider bound, and reports list it under Limitations.See Align a clock by hand.
Marking banner: The system-high marking fixed at the top of every console screen and repeated in the status bar, either CUI or UNCLASSIFIED.See CUI marking.
MGRS: Military Grid Reference System, the position format Foxborne uses on screen and in reports. Foxborne shows it at 10 m precision, such as 13R FP 7640 8765.See Read the map.
NTP: Network Time Protocol. It keeps the ground receiver's clock on UTC, to ±15 ms in the example dataset.See Clocks, anchors and error bounds.
Observed: The evidence level for a value, event or log line captured directly. Rule wording starts with Observed, except for clock_uncertain, which starts with Warning.See Evidence levels.
Open question: A question recorded on a report. It travels with the case file until someone resolves it.See Write and review a report.
Order unknown: The verdict for two events on different clocks whose error intervals overlap, so either could have come first. In INC-0142, the last obstacle_distance sample and the kernel kill are 39 ms apart inside a 46 ms combined bound.See Alignment and event order.
Ordering bound: The error above which Foxborne makes no before or after claim between two sources, whatever the times say. It is 2.0 s by default, and admins can set 0.5, 1.0 or 5.0 s instead.See Clocks, anchors and error bounds, Limits and defaults.
Original: An imported file exactly as it arrived, hashed with SHA-256 on arrival and stored write-once. Each excerpt in a report traces back to one.See Evidence integrity.
Parser version: The parser and version that read a file, such as ulog 0.9.2, shown for each file on the run page. Parsing the same file with the same parser version gives the same event IDs.See Check a run.
Process samples: The collector's per-process records of CPU, resident memory and restart count, in collector JSONL. They share the companion journal's clock through the boot ID.See Collector JSONL records.
Quarantined: The status of a file that claims a supported format but cannot be read in full, such as a truncated flight log. Nothing from it is shown as complete.See Import statuses and fixes.
Receipt rug: The timeline lane that draws one tick per message the ground receiver recorded, so a receive gap shows as empty space.See Read the timeline.
Receiver: The MAVLink receiver at range control, which listens to telemetry on the ground and records every receipt with its own clock.See MAVLink ground receiver.
Redaction: Removing sensitive content: patterns the collector replaces with [redacted] on the vehicle before upload, and coordinates removed from exported reports unless the exporter keeps them.See Retention, holds and redaction, Set the collector policy.
Rejected: The status of a file Foxborne does not read, such as an unsupported format, an encrypted flight log or a file above the size limit. The reason appears with the file.See Import statuses and fixes.
Report: An incident's hand-off document: the engineer's finding, the sequence, evidence excerpts with hashes, limitations, open questions and the next check, under your marking.See Reports and case files.
Rule: A deterministic detection with a fixed threshold, scope and wording. Each result records the rule version, its threshold and the events it read.See How rules work.
Rule version: The version a rule carries, such as telemetry_gap 1.3. Saving a changed threshold creates the next minor version, and findings keep the version that produced them.See Rule versions.
Run: One flight or bench session and the files that record it, such as its flight log, companion journal, process samples and ground receive log.See Runs, vehicles and incidents.
SBOM: Software bill of materials. Each Foxborne release carries one, SPDX 2.3 with 412 components for 1.4.2, and the installer checks it along with the signature.See Release signing and SBOM.
SCIM: System for Cross-domain Identity Management. With it on, your identity provider provisions Foxborne users and groups, and removing someone there removes them here within five minutes.See SCIM provisioning.
Sequence: The events a report walks through in time order, each with its time, bound, evidence level and a reference to its source.See Write and review a report.
SHA-256: The hash Foxborne computes for every original on arrival. Reports quote each excerpt with its file's SHA-256, so anyone holding the original can check it.See Evidence integrity.
Signed bundle: A Foxborne update as an .fxb file that your administrator brings in. Foxborne checks its signature against the Foxborne release key before anything installs.See Install an update, Release signing and SBOM.
Source: One kind of evidence in a run, such as the flight log, companion journal, process samples or ground receive log. On the Sources page, a source is also a read-only connection that Foxborne reads files from.See How data gets into Foxborne, Connect a storage source.
Spool: The collector's store on the vehicle while it has no uplink. Samples leave it only once their upload is acknowledged, and low-priority samples go first when the budget fills.See Set the collector policy.
System ID: A vehicle's MAVLink system ID, sysid in receive records. Foxborne matches flight logs to vehicles by it.See Receiver JSONL records.
SYSTEM_TIME: A MAVLink message in which a system reports its UTC time and its time since boot. Collector 0.8.1 records SYSTEM_TIME pairs, which give companion evidence a shared anchor with the flight log.See Clocks, anchors and error bounds.
System use notice: The notice on the sign-in page that everyone acknowledges before each session. Admins set its text in Settings, and each change is audited.See CUI marking.
telemetry_status: The uORB topic each PX4 MAVLink instance publishes about its link. Its heartbeat_type_gcs flag turns false once 2.5 s pass without a ground station heartbeat (HEARTBEAT_TIMEOUT_US).See telemetry_gap, failsafe_entered.
ULog: PX4's binary flight log format, with the file extension .ulg. Foxborne recognizes it by its first bytes, 55 4C 6F 67 01 12 35.See PX4 ULog.
Unknown: The evidence level for a question the evidence cannot decide, because sources are missing, partial or disagree on time.See Evidence levels.
uORB topic: A message stream on PX4's internal publish and subscribe bus, such as vehicle_status or sensor_gps. The flight log records selected topics, and topic_stall flags one that stops updating.See PX4 ULog, topic_stall.
US person: A status your identity provider asserts in the usPerson SAML attribute. It gates evidence marked EXPT.See Export-controlled evidence.
Vehicle: A platform Foxborne has evidence for, identified by its vehicle ID and MAVLink system ID. Its page shows its failsafe parameters and the changes between runs.See Vehicles and parameter drift.
Write-once: How Foxborne stores originals: written once and never rewritten. Reviewers annotate beside the evidence, never on top of it.See Evidence integrity.