Vehicles and parameter drift

The vehicle pages collect what your imported files say about each platform. They show the PX4 version it ran, where each kind of evidence is recorded on it and the failsafe parameters its flight log carried. Nothing on them is live.

Check them before you compare two incidents. When a parameter changed between runs, the same link loss can give a Hold on one run and nothing on the other.

Before you start#

• Anyone who can inspect original evidence can read the vehicle pages.
• Parameters come from the flight log, so a vehicle needs at least one imported .ulg.
• The examples use UGV-02 and UGV-05, T4 tracked UGVs from the example dataset.

Read a vehicle#

1. 01

   Open the Vehicles list

   Select Vehicles in the sidebar. The page reads Every platform Foxborne has evidence for, what it runs, and what its last logs say about its configuration. Configuration comes from the imported logs; collector state is the last report from the vehicle. At the top right, Collectors opens Sources, Vehicle collectors, and Add vehicle adds one to the roster.

   Vehicles are grouped by model. Each group has a line drawing and a count, with the model's role and drive. The example dataset has two models. T4 tracked UGV reads "Route clearance and breaching support. Skid-steer tracks, PX4 rover (differential)." Q4 recon quad reads "Route reconnaissance. Quadcopter, PX4 multicopter."

   Card field	What it shows
   Vehicle ID	Such as UGV-02, with a chip such as 1 open when the vehicle has incidents that are not closed
   PX4	The PX4 version, such as v1.16.0
   Collector	Reporting, Buffering offline, Offline or No collector
   Last run	The date and label of the latest run, or None

   Each group shows 10 cards a page.

2. 02

   Open a vehicle

   Select a card. The page title is the vehicle ID and model, above its role and drive. Runs opens the Runs list filtered to this vehicle. A vehicle with no collector also shows Enroll the collector, which opens Vehicle collectors.

   The summary strip for UGV-02 reads Serial T4-1042, MAVLink system ID 22 and PX4 v1.16.0. It goes on with Companion Jetson AGX Orin 64 GB, Ubuntu 22.04, Host ugv02-agx and Collector Reporting.

3. 03

   Read where each source is recorded

   Where each source is recorded, subtitled From the platform definition, draws the platform and labels each part with the evidence that covers it. On the vehicle page every source counts as present. See The evidence diagram.

4. 04

   Check the failsafe parameters

   Failsafe parameters lists the values from the vehicle's latest flight log, with a subtitle such as From R-0934, 25 Sep. Its columns are Parameter, What it sets and Value. Values with a meaning carry it in parentheses, such as 1 (Hold).

5. 05

   Look for changes between runs

   When a value differs from the run before, the Failsafe parameters header gains a button that counts the changes, such as 1 change between runs. It opens the Changes between runs drawer, which lists each change, newest first, with a link to its run. UGV-05 shows 2 changes between runs:

   NAV_DLL_ACT 0 (Disabled) to 1 (Hold) in R-0924, 22 Sep
   NAV_DLL_ACT 1 (Hold) to 0 (Disabled) in R-0917, 19 Sep

   R-0917 was a berm line link test that ran with NAV_DLL_ACT at 0 by its test plan, between runs that logged 1. INC-0137 records the consequence: PX4 continued the mission without the ground link.

6. 06

   Follow the runs and incidents

   Runs lists every run on the vehicle, newest first, 10 to a page, with label, ID, date, status and length; In the run list opens them on Runs. Incidents lists every incident on the vehicle with its status. Select a row to open it.

Failsafe parameters#

PX4 v1.16.0 defines COM_FAIL_ACT_T as the delay between a failsafe condition and the failsafe reaction, 5.0 s by default. UGV-02's latest log, from R-0934, carries COM_DL_LOSS_T 10, NAV_DLL_ACT 1 (Hold), COM_FAIL_ACT_T 5, COM_OF_LOSS_T 1, COM_OBL_RC_ACT 5 (Hold), SYS_HAS_NUM_GNSS 1 and COM_GNSSLOSS_ACT 0 (Warning). PX4 parameters Foxborne reads covers each one against the PX4 source.

How drift is found#

Foxborne takes the vehicle's runs that have a flight log and parameters, newest first, and leaves out rejected and quarantined runs. It compares each run with the one before it, parameter by parameter. Every difference becomes a line under Changes between runs: the parameter, the old and new values, the run and its date. The list shows up to 6 lines.

A change is a fact about the configuration, not a finding. Read it next to the incidents. On R-0917, NAV_DLL_ACT 0 meant PX4 took no action on the lost link. From R-0924 on, the same loss selects Hold once COM_DL_LOSS_T runs out.

The evidence diagram#

The diagram puts a line drawing of the platform in the middle, the T4 seen from above and the Q4 from the side. Each part gets a callout box on a leader line that ends in a small square where the part sits on the drawing. Those placements are illustrative, not measured from a real vehicle.

The radio, the GNSS receiver and the sensor sit above the drawing, and Range control sits to the right. The flight controller, companion computer and battery sit below. Each row runs in the order its parts appear across the drawing, so no two leader lines cross.

Each box gives the part, a short specification and a tag.

A dashed line runs from the radio to the Range control box. Once the incident's evidence shows the ground receiving nothing, that line turns amber and the Range control tag reads Nothing received.

Wiring between parts is drawn as dotted lines, straight from part to part over the drawing. A link the evidence shows down turns amber and heavier. Vehicle parts and their logs lists every part and connection of both platforms.

Badges follow the report#

On the Reconstruction tab the diagram appears as On the vehicle, subtitled Where each event happened. Numbers follow the report. Numbered badges sit on the parts where the report's events happened. The numbers are the report's evidence references: badge 2 is E2.

Select a badge to select its event. The selected event's badge, box and leader line are highlighted.

A badge marks where an event happened, which is not always the part whose log recorded it. In INC-0143, the companion's kernel logged the USB disconnect, and badge 2 sits on the mesh radio. A sequence event that the incident ties to no part, such as E5 in INC-0143, has no badge.

The diagram follows the cursor: the time under the pointer on the timeline, else the selected event, else the incident's first finding.

In INC-0143, the radio box on UGV-02 turns to State not observed once the kernel reports USB device 1-2.3 disconnected at 15:41:02.604. It returns when usb0 registers again, 29.61 s later. Before the disconnect and after the return, the radio reads Keeps no log: Foxborne never observes the radio's own state.

Add a vehicle#

Select Add vehicle on the Vehicles page. The dialog's note: "Foxborne matches imported files to a vehicle by its MAVLink system ID. Nothing is sent to the vehicle."

Select Add vehicle. The vehicle page opens, the toast reads, for example, UAS-11 added. Enroll its collector from Sources when it is on the network., and the audit log records Added vehicle. An ID or system ID already in use is refused, such as System ID 22 is already used on this range.

Check the result#

• The vehicle card shows the PX4 version and collector state you expect.
• Failsafe parameters names the latest run you imported for the vehicle.
• Failsafe parameters shows no change button, or Changes between runs lists only changes you can account for.

Troubleshoot#

No flight log yet. The panel adds "Import a flight log to read its parameters." Import files in the console.

No runs yet. Nothing has been imported for this vehicle.

A change you expected is missing. Drift leaves out rejected and quarantined runs, and runs without a flight log, such as bench runs.

This vehicle does not exist. Check the ID. Back to vehicles returns to the list.

The collector reads No collector or Offline. See The companion collector and Install and enroll the collector.

Next#