Smiths PVD
The PVD was developed by Smiths Industries in the UK around 1961.
The original intention was to have one vertically and one horizontally mounted barbers pole in the pilot’s peripheral vision to provide guidance during approach and landing. This configuration was not very effective, I'm not sure if any aircraft actually used it in service.
It was used on Trident aircraft, only utilising the horizontal pole mounted in the glareshield for guidance on the runway, I seem to recall that it was driven by its own separate computer; so most likely a CAA requirement for Cat 3 landings at that time.
I have not been able to locate any pictures.
QA1