As the manual PART II – Aircraft and Systems, says in page 68:

6. Navigation Source Selector
Autopilot will track CIVA-INS flightplan:
- Autopilot Mode Selector should be in MAN position;
- Autopilot HDG Switch should be engaged;
- Autopilot Navigation Source Selector - pos AB;
- Heading Bug on Captain's HSI will be controlled by CIVA-INS.

So it looks like an improvement of  CIVA mplementation.