The ALS-2 is a sensor designed to provide an accurate and reliable determination of the amount of background light during all weather conditions.


  • Digital or analogue output
  • Extensive self-checking
  • Field calibration can be carried out using the optional automatic ALS-2 Calibrator
  • 2 years warranty
Such a sensor is usually referred to either as an Ambient Light Sensor (ALS) or Background Luminance Sensor. Such sensors are typically used as part of a system to determine the Runway Visual Range at an aerodrome. The ambient light received by the sensor’s 6° field of view is focussed onto a photodiode of similar spectral response to the human eye. The output from the photodiode is used to determine the ambient light level using the standard (SI) units of candela per square metre (cd/m2), averaged over one minute.

Background Luminance Meter ALS-2 - Product sheet