Are there standards for digital sensor links?
In avionics (particularly flight safety critical) it is not unusual to see the usual comms (SPI, I2C) within a box, but externally it is usually going to be ARINC 429 (civil) or MIL-STD-1553B (Military) to / from sensors.

There are others such as STANAG 3910 which is used on Typhoon.

Within a system that communicates between boxes (not aircraft level) it is not unusual to see manchester encoded signalling.

I have also seen interfaces use HDLC / SDLC.

Oddly enough, the update rate for flight safety critical equipment is not that fast; typically 50Hz or so (put that in perspective for moving a flying control surface at a 20 milliseconds update rate)