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The fact that the code disables optical nav at low altitudes is also one of the reasons it landed safely.

Yes, but in this case that was just good luck. As the article mentions, the low-altitude behavior is because of concerns regarding dust. It was not intended to provide robustness in the face of glitches in the optical navigation system.

Dust concerns were one reason, but avoiding glitches and ensuring the smoothness of position data is another.

> Then, once the vehicle estimates that the legs are within 1 meter of the ground, the algorithms stop using the navigation camera and altimeter for estimation, relying on the IMU in the same way as on takeoff. As with takeoff, this avoids dust obscuration, but it also serves another purpose -- by relying only on the IMU, we expect to have a very smooth and continuous estimate of our vertical velocity, which is important in order to avoid detecting touchdown prematurely.

https://mars.nasa.gov/technology/helicopter/status/298/what-...

I wonder if, had Ingenuity disabled the visual system upon noticing timestamp conflicts, the use of the IMU alone would have made the entire situation a more safe one.

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