Alternative to Pitot
Looking for a different option for determining IAS, what about a "reverse style" pitot that measures vacuum pressure. That way it will not get blocked. Anything in it will get sucked out. Something like a trumpet facing backward. If it needed clearing, just let some cabin air into it, say, every 30 seconds. Probably no need to have the ability to heat it either.
If you know altitude, outside air temp/pressure, and with some sensitive vacuum gauge/wizardry, it should be possible to determine IAS with greater reliability than using pitots.
Has anything like this ever been considered?