What's the difference between EFVS and CVS? Is there any aircraft certified with EFVS?
The FAA recognizes 4 'vision' systems; enhanced vision system (EVS), synthetic vision system (SVS), combined vision system (CVS), and enhanced flight vision system (EFVS).
EVS and EFVS use either passive or active sensors on the aircraft to enhance the crew's vision of the approach. SVS uses a database to generate a synthetic view of the terrain in front of the aircraft. CVS combines features of EVS or EFVS and SVS.
It's all spelled out in AC 20-167A Airworthiness Approval of Enhanced Vision System, Synthetic Vision System, Combined Vision System, and Enhanced Flight Vision System Equipment
I can’t find a solid confirmation of this, and hopefully someone will fill in the blanks, but Combined Vision Sytem (CVS) appears to be a system that shows both Enhanced Vision System (EVS) and Synthetic Vision System (SVS) data simultaneously on the HUD.
An EVS image is created from the actual environment using sensors on the aircraft. An SVS image is created from a terrain database. CVS systems allow the pilot to see these two simultaneously. There are currently two ways to do this. Honeywell and Rockwell Collins systems approach is to overlay the two. Dassault’s FalconEye system allows the HUD to be split between the two at a line chosen by the pilot.
For more info see Flying Dassault's FalconEye Combined Vision System