What happens if you lose line of sight to your UAV or your FPV videolink breaks down?

If you still have a working telemetry link, the PFD-display of the UxV-CS might just help you bring your bird back in one piece.

It shows a simplified attitude indicator (the display isn't designed for heavy graphics), a compass rose with a heading bug showing the bearing to the home location and airspeed, speed over ground, vertical speed and altitude. If you know your terrain, with that data you should be able to get you UAV back into LoS / FPV-range.