Keep the current GPS software and Genesys2/VCU118 flows while integrating Ti375C529 Efinity, flash, programming, and debug support. Add board-specific SPI NOR profiles and persistent GPS flash layouts across all three boards.
Add freestanding S25FL256S read/program/erase/verify support and seed a newly formatted ephemeris store with stale records. Age-gate navigation readiness, persist the continuous Toe week, and regenerate the Genesys2 MAX2771 integration and flash image.
Persisting navigation data changed its lifetime from one power cycle to
weeks, and every piece of arithmetic that had only ever run over the
shorter lifetime turned out to be wrong. Each fix below reproduces in a
host test that fails against the previous behaviour.
Almanac (gps_almanac.c, gps_lnav_parser.c)
WNa was lifted against gps_ephems.toe.week, a field nothing ever writes,
so any WNa above 128 underflowed to ~4.29e9. The propagation then reduced
tk with a while-loop, turning one visibility refresh into 4.29e9
iterations - hours on the target, inside a 10 s periodic call. WNa is the
week modulo 256, so this armed at GPS week 2433 and then for 127 weeks in
every 256. Now lifted against tow.week in signed arithmetic, refused if
impossible, and the propagation is closed form.
The IS-GPS-200 20.3.3.5.2.3 half-week wrap was also applied to tk
unconditionally. It is a week-crossover correction, not a general
reduction: a GPS week is 14.0384 orbital periods, so aliasing one week
moves a satellite 5161 km, enough to report one 5.1 degrees below the
horizon as 5.7 above. The crossover guess now lives in
gps_almanac_assumed_week(), used only before page 25 arrives, and an
almanac too old to propagate yields no prediction rather than a wrong one.
Ephemeris age (gps_ephemeris_validity.c, gps_lnav_parser.c)
The curve-fit check compared two second-of-week values and never read a
week at all, so a record exactly N weeks old read as current. Harmless
while ephemeris lived in RAM; directly reachable once persisted across a
power-off. gps_resolve_toe_week() now reconstructs Toe's week at commit
time from the subframe 1 week number and the handover word; an
unresolvable week yields no age, which reads as a rejection.
A restored record could also outrank the live broadcast, because the Toe
ordering inverts past half a week. Flash records are now marked restored
and are candidates, never incumbents.
Flash wear (gps_nav_context_store.c, gps_interrupt_handlers.c)
The CRC wear policy never engaged: the payload carried the live WLS
position and a receiver timestamp nothing on the restore path read, so
every 60 s save was an erase - about 139 days to wear-out. The seed is
now held and refreshed only on 5 km of movement, at most hourly: one
erase per day instead of 1440.
Measurement model (NavEquations.c)
The elevation weighting was floored at 10 degrees, capping its term at
17.3 m where the model's own answer is 34.4 m at 5 degrees and 86 m at 2,
so a low satellite was trusted several times more than the model allowed.
Floor lowered to 3 degrees, which is where 1/sin must still be bounded
because a zero weight fails the whole epoch. Measured on a six-satellite
geometry, 30 m of uncorrected delay now moves the fix 4.18 m through a
4-degree satellite against 48.50 m through a 72-degree one.
Both atmospheric corrections switched off below the horizon, so a
satellite crossing it lost 78.8 m of tropospheric delay in one step.
Elevation is now clamped at the horizon for the models, and the
extrapolation is paid for in variance.
Also: gps_pps_select_reference() returned early on the preferred PRN,
leaving later non-finite capture times unscreened.
Checked and found correct, with regressions added: the epoch assembly
under satellite connect/disconnect and reassignment, coalesced captures,
the 32-bit RF sample counter wrap (pseudoranges agree to 3.3 um across
it), the refusal to publish a solvable subset of an incoherent epoch, and
the Klobuchar model against IS-GPS-200 20.3.3.5.2.5.
Tests: 22 host suites, 5 RTL testbenches, sanitizer clean.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
The existing suite passed both before and after the fusion fixes, so it
never covered either failure. Two tests close that gap; both were checked
against the pre-fix sources and fail there.
calibration_offset_test reproduces the bench part's +28 mg zero-g offset
and requires startup to complete, while still refusing a sustained 3 m/s2
acceleration. It also asserts the blind spot rather than leaving it
implicit: horizontal acceleration adds to gravity in quadrature, so
1.5 m/s2 moves the magnitude by only 0.11 m/s2 and is not separable from
offset by any accelerometer gate. Separating it needs GNSS velocity.
long_outage_trajectory_test drives pedestrian, gentle-car (0-100 km/h in
30 s), slow-city and isolated-mount profiles across 1 and 5 minute
outages, using the production rest supervisor rather than a hand-set
flag. Only the isolated-mount slow-city case reproduces the field bug:
GNSS motion evidence compares displacement against covariance, so 4 m/s
under 6 m sigma scores a displacement NIS of 0.22 against a 9.21 gate and
reads as stationary, whereas highway speed scores 42.9 and is correctly
called moving. Pre-fix that case produces 608 zero-velocity updates while
driving, matching the 609 in the board logs.
Drift is judged against the filter's own covariance rather than a fixed
distance. Five minutes unaided legitimately reaches kilometres on this
hardware; what must not happen is the error outrunning the covariance,
which is divergence rather than honest coasting.
tdk_noise_test characterises the sensor at rest through the production
driver, so ODR, full scale, UI filter and LSB scaling match the flight
build, and reports the norms fusion_motion_update() actually gates on.
It also carries an INT1-to-PLIC continuity test that drives the pin to a
static level and reads the PLIC pending bit directly, separating a broken
line from a source that never fires.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Tuning the velocity covariance floors and the zero-velocity veto
threshold needs the receiver's velocity noise, which cannot be recovered
from the existing records: the raw observation and the filter state were
logged in different lines at different rates, so they could not be
differenced.
Hold the converted ENU Doppler velocity from the last fix and publish it
alongside the filter state in one line at one instant, with their
difference (the velocity innovation) and the at-rest flag. With the
platform still, the raw reading is the noise itself.
An IMU does not measure speed; the eskf_* fields are the integrated
result after GNSS correction, and are the only inertial speed available.
First capture, stationary: per-axis sigma 0.12 E, 0.25 N, 0.59 U m/s.
The vertical channel carries most of it, which the previous scalar speed
field could not show.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Halting the core with a debugger, or resetting it while a transaction is
in flight, leaves the sensor's SPI shift register part-way through a
word. Every later access is misaligned, WHO_AM_I reads back 0x00 and
initialisation fails, which is the `sensor=none who=0x00` case in the
field logs.
Toggle chip select around idle bytes to return the device to command
state, then soft reset so the register file starts from defaults
regardless of what the previous image was doing.
This covers the sensor-side wedge. It does not recover a wedged fabric
SPI controller, which a CPU-only debugger reset does not touch and which
was observed to need a board power cycle.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
A cruising vehicle produces almost no specific force and almost no
angular rate, so an inertial rest supervisor declares rest while moving.
The engine trusted that flag, and three circular dependencies then locked
the filter out of GNSS entirely:
- GNSS motion evidence was derived only from accepted fixes, so it
froze exactly when a rejection storm made it the one signal able to
veto a false zero-velocity update.
- The zero-velocity update pinned filter velocity near zero, which kept
eskf_speed_mps() below the rest-detector speed limit and latched the
mistake, and clamped the position covariance to metres while the true
error grew to hundreds.
- Position recovery, the intended escape, was gated on being at rest --
unreachable during the moving divergence that needs it.
Field logs show the result: 91 m from GNSS with a 5 m sigma, every fix
failing the NIS gate, gps_age_ms climbing past 40 s and recoveries=0.
Motion evidence now comes from every fix on its own displacement
baseline; accepted Doppler speed vetoes the zero-velocity update and is
taken from the measurement rather than the update outcome, since a filter
that has drifted far enough to reject it is the case that matters; and
that veto latches until a later fix shows low speed, because an unaided
platform gives no evidence that it has stopped.
Startup calibration is fixed alongside it. One tolerance served both as
the sensor zero-g offset allowance and as the motion gate, so the bench
part's in-spec +28 mg offset consumed 93% of it and left no headroom:
calibration_samples thrashed 0,3,0,4,2,1 and never reached the minimum,
so the engine never left CALIBRATING and no fused location was published
at all. The offset allowance is now applied to the calibration window
mean, where a fixed bias actually shows up, leaving the full tolerance to
reject sustained acceleration.
Rest-detector thresholds move into the per-sensor quality profile and are
sized from a stationary bench capture rather than datasheet noise
densities, which describe the bare part and not this board or bandwidth.
Verified on hardware: calibration completes in ~2 s, 1980 fixes accepted
with 1 rejection, sub-metre sigma, gps_age_ms mean 223 ms.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Wait for every navigation-ready tracking channel in a GPS epoch, remove unlocked channels without a timeout, and keep late joins for the next epoch. Reset PLIC ownership during warm initialization and extend Linux synthetic, integrity, and fake-MMIO regression coverage.
onur cayan
onur