First transmission through a real radio path in the project. A 4756-byte
JPEG went from transmitter to receiver over two antennas 60 cm apart at
225 MHz and reassembled byte-identical, reproduced across three runs.
The cable loopback still needs an SMA male-to-male adapter that has not
arrived, so this air run is a track verification, not the controlled
measurement: room levels are not held the way a cable holds them. Its
purpose was to exercise the device wrapper the models cannot cover.
Four defects the software model passed but the hardware exposed, each
reproduced and fixed:
- a 566 528-sample frame did not fit the 262 144 receive buffer, and the
sample stream is not continuous across separate reads, so a frame on the
seam was destroyed. Reception now uses one buffer sized to the frame
- carrier correction was always applied, but with a shared reference the
true offset is near zero and the 80-symbol marker estimate is noise;
correcting by it rotated phase along the whole frame, 65% bit errors
measured. Ported should_apply_cfo_correction from Lab023
- receiver gain of 20 dB left the signal at 0.0003 of full scale. Levels
set by measurement: RX 50 dB, TX -10 dB give zero bit errors with margin
- the error-vector metric returned zero on a failed receive, reporting a
perfect signal where there was none, the same class of defect as the
written-in figures of Lab041. Replaced with an explicit not-computed value
The air TX gain ceiling is now derived from the link budget by antenna
distance rather than a constant. Three loopback modes: software, cable,
air. PROJECT_LOG entry 019 records the run and the defects.
Software and cable results stay reproducible; 125 tests pass, gate passes.
Two more suites, 69 checks, bringing the fast tests to 125 in 0.3 s.
test_control_messages: roundtrip for all ten message types, a guard that
fails if a type is added without a test, wrong version, unknown type,
truncation, the control-state range rules including negative and
non-finite speed, and sequence comparison across the 32-bit wrap and the
ambiguous 2^31 boundary.
test_session_state: the safety properties that previously only ran inside
Lab041. Safe boot on both sides, status and authorization not being a
movement command, a new operator command being required, stale session,
boot and epoch identifiers, replay, sequence wrap, ambiguity, persisted
emergency intent surviving a restart, acknowledgement not clearing it,
ordinary commands not releasing the latch, idempotent reset, and reset
not restoring the previous command.
Two of these were literal zeros in the Lab041 report and measured
nothing: negative speed and speed above the limit are now genuinely
exercised against the encoder.
PROJECT_LOG entry 018 records the RF architecture decision: 200-250 MHz
with frequency hopping, a directional ground antenna and spread spectrum
for the command channel, with the rejected alternatives and why.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Audit found seven numbers in simulate_trial that were neither modelled by
Lab041 nor traceable to their claimed source. Video fraction 0.910 did not
match Lab040 (0.9603); base queue length 31 did not match Lab040 (36-38).
- drop video/telemetry/control delivered fractions and queue length: these
belong to Lab037 and Lab040 and are not modelled here
- drop lab041_traffic_impact.png, which plotted only those metrics
- drop negative_speed_cases and speed_limit_exceeded_cases, never computed,
along with the tautological asserts that checked them
- bind braking parameters to the Lab039 nominal profile via named constants
instead of the literals 0.250 and the divisor 6.0
- cite Lab038 as the source of the transferred video and telemetry loads
- rewrite the invariants section: nine architecture-derived properties now
carry functional-check references, five unmeasurable ones move to their
own section
- extend check 04 with negative speed and the 15 m/s boundary
- state explicitly what the matrix rolls, what the architecture fixes and
what is not modelled at all
Regenerated: 180 combinations, 24/24 checks, five CSV and seven PNG.
Six columns removed, no retained value changed.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
