Jacob Dahl b4f9388cd9 fix(drivers/imu): clip FIFO samples against the declared range, not the int16 rail (#28310) ...

* fix(drivers/imu): clip FIFO samples against the declared range, not the int16 rail

updateFIFO() counted a sample as clipped only within 1 LSB of INT16_MIN
or INT16_MAX, while update() compares against _clip_limit (range/scale).
The two agree only for sensors whose sensitivity is exactly range/32768.
ST parts leave headroom in the word: the LSM6DSV80X high-g channel at
+/-80 g and 3.904 mg/LSB saturates at 20492 counts, its gyro at
+/-4000 dps and 140 mdps/LSB at 28571, the LSM9DS1 and ADIS16607 are
similar, and the BMI055's 12-bit accel word never reaches the rail at
all. None of them could report a clip on the FIFO path, so the EKF's
delta-velocity clipping handling never engaged on those sensors.

Compare against _clip_limit on the FIFO path as well. For rail-scaled
sensors the threshold moves from 32766 to 32735 counts (the existing
0.999 margin), which is what the non-FIFO path already used.

* docs(msg): SensorGyroFifo/SensorAccelFifo counts are raw, not SI

x/y/z are int16 counts; SI is count * scale. The comments called them
rad/s and m/s^2, which is what sensor_gyro/sensor_accel carry.

Signed-off-by: Jacob Dahl <dahl.jakejacob@gmail.com>

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Signed-off-by: Jacob Dahl <dahl.jakejacob@gmail.com>

2026-08-28 21:13:44 -06:00

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