Is certainly a technical possibility.

The navigation programmatic functions are undertaken within the drive itself, so you would need to replicate those (hardware and software infrastructure, as well as application programming).

Then, after that, it's just maps.

There are considerations - what are the limitation of the inputs (from the head unit) and outputs (to the head unit), but from a technical exercise perspective, its sure possible.

Above my pay grade, but would be really keen to hear of any technical analysis.

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Cheers,

Anthony