Visibility Sensor FS11

Designed according to ICAO, FAA, and WMO guidelines, the FS11 is an ideal instrument for runway visual range (RVR) assessment and airport visibility measurement, as well as other demanding applications. It provides the optimal combination of the best accuracy, the highest reliability, broad measurement range, and low maintenance needs.

Benefits

The main applications of FS11 are runway visual range (RVR) and synoptical and aeronautical visibility measurements. FS11 is also well suited for other demanding applications, such as visibility measurement at ports and harbors.

Scientifically Valid Chain of Calibration

FS11 is calibrated through a scientifically valid chain of reference. The scattering response of the calibration device can be clearly traced to a reference FS11 visibility sensor, which is in continuous operation at Vaisala outdoor test field along with reference transmissometers and other

instrumentation. The visibility measurement of FS11 is also traceable to FAA reference sensors.

Low Maintenance Need

FS11 incorporates a technique that measures and compensates for window contamination. It ensures unparalleled measurement accuracy between window cleanings. It also enables much longer window cleaning intervals than compared to conventional visibility sensors. The unique system works by monitoring the total reflectance of the window surface. It automatically compensates for visibility measurement errors caused by window contamination. The sophisticated self-diagnostics and modular design allow for very short service times. The measurement fork and optional background luminance sensor LM21 are independent instruments that can be replaced quickly as pre-calibrated spare parts.

Reliable Operation in the Harshest Weather

Four main design features are combined in FS11 to ensure reliable operation in the harshest weather. The first is the window contamination compensation technique. The second is the “head-down” design of the optical heads, which protects them against virtually all windblown particles (even those flying horizontally). High-power heaters are the third feature. Each heater has its own temperature monitoring and control mechanism to prevent snow accumulation during the heaviest snowstorm. As a final measure, there is an optical path clearance monitoring circuitry to verify that measurement is not affected by obstructions.