SWS-050 and SWS-250 Visibility and Present Weather Sensor

Posted on 12th February 2015 in News

Biral launches three new sensors for aviation applications
Biral has extended its SWS range to meet the budget expectations of many regional airports across the globe, and upgraded the successful ALS ambient light sensor.   The new products are:



Made to Biral’s high precision engineering standards, the new SWS-050 visibility sensor is designed to monitor visibility and obstruction to vision caused by dust, fog, rain, drizzle, snow and hail.

With a measurement range of 10 metres to 40 kilometres the sensor is ideal for use in aviation applications, particularly for end of runway use.

The SWS-050 uses a compact, forward scatter design ensuring that the output is both accurate and reliable in all weather conditions and will not be influenced by local light sources even those that flash.

Constructed from robust aluminium and finished with a high quality powder coating, the sensor will give many years of reliable service. Featured as standard is heating of the optical windows and sensor hoods, permitting use in the harshest conditions. Both optical windows are monitored for contamination and visibility output is automatically compensated to reduce maintenance requirements. An ambient light sensor can also be easily integrated with the SWS-050 sensor making it an excellent choice for aviation applications where both RVR and METAR data is needed. An optional calibration kit is available, which allows calibration in the field to be carried out simply and quickly.



Introduced as part of the same range, the new Biral SWS-250 incorporates a back scatter receiver to form a visibility and present weather sensor.

Designed for both runway use and ‘met gardens’, the SWS-250 has a visibility performance up to 75km and reports 39 WMO 4680 codes. The sensor measures visibility (MOR, EXCO and TEXCO), fog, haze, drizzle, snow, hail and other non-frozen precipitation according to WMO-4680. METAR coded outputs are also provided.


The enhanced present weather information from the SWS-250 is due to the back scatter receiver which allows detailed precipitation analysis and the use of algorithms developed for Biral’s flagship VPF-750 present weather sensor.

Built to a high specification, in powder coated aluminium for long and reliable service, the SWS-250 can be integrated with an ambient light sensor for use in aviation applications where both RVR and METAR data are needed. An optional calibration kit is available, which allows calibration in the field to be carried out simply and quickly.


Also on show at ATC Global for the first time is the new Biral ALS-2, an ambient light sensor designed for use in ICAO compliant RVR (runway visual range) systems.

The ALS-2 sensor is a significantly upgraded version of Biral’s original ALS and is designed to Federal Aviation Authority (FAA) requirements. There are options of serial or analogue output and the ability to be used stand-alone or integrated with a Biral visibility / present weather sensor.

Power for the ALS-2 is taken from the visibility / present weather sensor with which it is integrating.   The 0 to 40,000 Cd/m² light reading is directly available in the sensor data message and the extensive self-test features of the ALS-2 can also be accessed via the serial interface.

A hood is fitted around the sensor window to make sure that viewing is unobstructed by precipitation. An option is available for automatic heating to prevent build-up of snow if the temperature falls below 2°C. Further options are available of additional internal heaters for extremely cold operation down to -40°C or even down to -55°C.
A field calibrator is also available to allow calibration of the ALS-2 sensor to be performed insitu without the need to remove connections. The calibrator is simple to use and reduces maintenance and assists in keeping downtime to an absolute minimum.
Further information on Biral meterorological instruments for aviation is available from Biral on +44 275 847787 email aviation@biral.com or by visiting the company’s website at www.biral.com