In the AGIVIS system, Runway Visual Range is measured with white light source transmissiometers with photopic sensor diodes. These accurately and realistically reproduce the eye response of the pilot viewing the runway lights. The optical transmission of the light path is measured at ‘touch-down’, ‘mid-point’ and ‘stop-end’.
The RVR value for each field site is automatically calculated by the FSEU from the optical transmission and background values using established physical equations.
The RVR is then transmitted via dedicated telephone lines to the AGIVIS control tower unit, where the data is disseminated, displayed and relayed to air traffic control, again automatically. The controllers receive the data via AGIVIS high-integrity IRVR displays.
The information is also entered onto a magnetic cartridge recorder and page printer for archiving and legal record purposes. A VDU keyboard provides the operator interface and is used purely for monitoring the input or output of data