Aeronautical & General Instruments Ltd (AGI): Airport Equipment

Runway Visual Range Systems

The AGI Runway Visual Range (RVR) systems provide a fully automated assessment and reporting of RVR through stand alone displays or as an input to AWOS systems.

Two different systems are available using transmissometers or forward scatter meters. The AGVIS FSI system uses a forward scatter sensor and the AGIVIS 2000 uses an AGI designed Transmissometer. Both systems comprise of:

  • Background Luminance meter
  • Runway Lighting interface
  • RVR computer

RVR Output is via stand alone displays or as an input to an AWOS system


The AGVIS FSI runway visibility (RVR) system uses a Biral VPF sensor This sensor combines forward scatter and backscatter sensors which enables it to measures the extinction coefficient from 10m to 75km and Present Weather. A background luminance meter in the AGI Field Site Electronics Unit measures the ambient light and the RVR computer located in the control tower has an interface to the airport's runway lighting system.

RVR is calculated in the RVR computer using the values obtained from the VPF 730 sensor, the background luminance meter and the runway lights intensity. The AGI software and algorithms using Allards and Koschmeiders Law (refer to White paper) has been proved over many years and meets the ICAO and WMO requirements for runway visibility and Meteorological Optical Range respectively.with AGI's experience in automated IRVR measurements, the AGVIS FSI system will provide years of trouble-free operation.

Automated Runway Visibility (RVR) measurements are becoming a requirement at regional airports with CAT 1 or CAT 2 runways. A Forward Scatter Meter is a cost effective solution rather than a Transmissometer based system. This paper describes the differences in the two systems and contains a business case that will be of interest to operators considering installing automated RVR systems.


The AGIVIS 2000 Runway Visual Range system uses an AGI designed Transmissometer to calculate the runway visual range.

The system comprises:

  • AGI Transmissometers (transmitter and receiver pair)
  • Integrated Background Illuminance Monitor
  • Integrated RVR computer
  • High contrast TFT or LCD displays

The Transmissometer and reflector are enclosed in specially designed housings. These are pressurised to prevent the ingress of wind driven precipitation, dust and foreign bodies.

The software system was written to UK CAA standards and has a proven record of reliability. For operator interaction, software routines ensure that the system is continuously monitored and alarm messages are easily understood.
The system exceeds the ICAO Annex 3 requirements for measurement accuracy and can be used on runways from CAT 1 to CAT 111b.


Wind is one of the critical measurements at an airport and the AGI Ultrasonic Wind System uses the latest technology to provide an accurate, reliable, but cost effective solution to airport wind measurements. Based on the Gill Wind Observer 2 ultrasonic anemometers, the UWS system combines the Gill sensor with the AGI Multi Function Aviation Display (MFAD).

The MFAD processes and displays all of the wind parameters essential to measure and record the airport surface wind. In addition to the main ICAO wind parameters, the UWS system will show the head, cross and tail wind measurements. This will enable the ATC personnel to inform the pilot of these important parameters to maximise the efficiency of both take off and landing.

Your local contact for AGI products is Owen International.