Optical Weather Identifiers

The OWI-430 DSP-WIVIS™ is the most advanced present weather and visibility sensor ever made. The fully automated instrument provides accurate visibility, present weather and precipitation measurement in a single sensor. This 3rd generation intelligent sensor uses all digital signal processing (DSP)
for no-drift high-accuracy results. OSi’s patented environmentally adaptive algorithms use artificial-intelligence technology derived from over 200 million field hours of real-world data from our sensors installed around the world. The result is the most advanced weather sensor in the world.

The DSP-WIVIS™ measures visibility and detects and quantifies rain, snow, drizzle, freezing and mixed precipitation conditions. The -DSH model identifies whether visibility impairments are caused by haze/fog vs. dust/smoke. The sensor is designed for year-round continuous operation in all climates from Antarctica to tropical rain forests. OSI’s advanced weather sensors provide critical weather information to airport, highway, military, research and meteorological weather information systems all over the world with over 3000 systems fielded. Sensing the environment is not a sideline business for us – it is our primary focus. When you need superior present weather information and high reliability, nothing else can match OSi’s DSP-WIVIS™.

Thanks to the new DSP electronics, the typical need for field calibration is completely eliminated. The single enclosure makes integration and installation simple. Adding the optional HIP-100 acoustic sensor provides for enhanced hail and ice pellet discrimination. The DSP-WIVIS™ is widely used by airports and regional DOT’s across the US and throughout the world. No other weather instrument can provide this powerful combination of high performance, low cost and proven reliability! No other company can provide the proven level of support and customer satisfaction that OSi does!

The OWI-650 LP-WIVIS™ has been designed from the ground up for quick deployment anywhere. The LP- WIVIS is the first present weather and visibility sensor designed for battery powered or solar powered applications.

The LP-WIVIS™ is more than just a sensor. It is a system. Other sensors including
wind, temperature, relative humidity, and barometric pressure may be easily added. The LP-WIVIS™ serves as both sensor and data acquisition system. No separate data acquisition system is required.

The fully automated instrument provides accurate visibility, present weather and precipitation measurement in a single sensor. This next generation intelligent sensor uses all digital signal processing (DSP) for no-drift high-accuracy results. OSi’s patented environmentally adaptive algorithms use artificial-intelligence technology derived from over 25 year’s experience and over 200 million field hours of real-world data from our sensors installed around the world. The result is the most advanced/easily deployable weather sensor in the world.

The LP-WIVIS™ is already a low power present weather and visibility sensor but to further reduce the power requirements the LP-WIVIS™ may be operated in intermittent mode. In intermittent mode, the sensor is automatically powered up for one minute, reports present weather and visibility measurements and then is powered down. The heaters are independently controlled. In many environments the heaters are never powered on. Advanced detection algorithms report dew or frost on lens and control heater function.

The LP-WIVIS™ measures visibility and detects and quantifies rain, snow, drizzle, freezing and mixed precipitation conditions. The sensor is designed for year-round continuous operation in all climates from Antarctica to tropical rain forests.

Thanks to the advanced DSP electronics, the typical need for field calibration is completely eliminated. OSi Sensors are widely used by airports and regional DOT’s across the US and throughout the world. No other present weather and visibility sensor can provide this powerful combination of high performance, low power, quick deployability and proven reliability! No other company can provide the proven level of support and customer satisfaction that OSi does!

Rechargeable batteries, solar power kits, spread spectrum radios, and additional sensors are all available options.

OWI-430 ADVANTAGES TECHNICAL BRIEF

The OWI-430 Optical Weather Identifier is a unique combination present weather and visibility sensor. Competitors such as Vaisala, Belfort, and Biral do not use the patented technique (Patent Number US 05444530) utilized by Optical Scientific Inc, (OSi). Unlike conventional forward scatter visibility measurement instruments, the OWI-430 is able to utilize signals from forward optical scatter, in-beam optical scintillation, ambient light, temperature, and humidity to accurately determine meteorological optical range (visibility), precipitation type (rain, snow, hail, drizzle, etc.) and precipitation amount.

The OWI-430 uses a compact, triple aperture optical system to measure both precipitation and visibility.The sensor frame is an all aluminum, welded design. As shown in Figure 1, the small box (TX) is the transmitter unit and contains an infrared Light Emitting Diode (LED) light source and lens with dual heaters. The large box (RX) contains two (2) independent optical receiver assemblies, each consisting of a photo diode, lens with dual heaters, and pre-amplifier electronics. One of the receivers detects present weather (in-beam) and the other detects visibility (forward scatter). The two signals are processed by a Digital Signal Processing (DSP) board located behind the two receivers. A light block is attached to the sensor arm during
the installation procedure to reduce stray transmitter light from entering the forward scatter receiver. The dual lens heaters which prevent dew, frost, and snow from building up on the lenses are self-regulating devices. They are “on” continuously but draw more current when the outside temperature is cold and less current when the temperature is warm. All wiring between transmit and receive heads is within the welded sensor frame.

On the underside of the OWI-430 are temperature and relative humidity sensors. The advanced algorithms in the DSP board are based on over 300 million unit-hours of field experienced OSi has gained over the past three decades. The algorithms analyze the outputs of the various sections of the sensor to accurately identify and measure precipitation and visibility.

Key advantages (summarized in Table 1) of the OWI-430 over the Vaisala PWD22, Belfort 6550, and Biral HSS VPF-700 visibility/present weather sensors include:

1. The ambient light sensor (ALS) is standard with the OWI-430. Competitors provide the ALS as a value added option.
2. The OWi-430 forward receiver and ALS use the same optics with exactly the same field-of-view, resulting in a more accurate / more representative ambient light measurement.
3. No other manufacturer of visibility/present weather sensors can match the sensitivity and reliability of precipitation detection (especially snow) of the OSi patented optical scintillation technology.
4. No narrow hoods over lenses prevent ice/snow blockage (due to hood ice/snow bridging) and insect nesting.
5. The OWI-430 includes temperature and humidity sensors. These added parameters further aid in the accurate discrimination of weather types such as snow, rain, drizzle, mist, fog and haze. The temperature and humidity data is also used to eliminate insect-induced false precipitation alarms.
6. With the addition of the acoustic hail and ice pellet sensor (HIPS) the OWI-430 provides superior snow, ice pellet, hail and freezing rain discrimination, far surpassing all other visibility/present weather sensors.
7. The OWI-430 uses both in-beam and forward scatter optical data to accurately determine meteorological optical range (visibility) and precipitation type and amount.
8. OSi’s advanced artificial intelligence algorithms and all digital design eliminate the requirement of field calibration. Unlike other manufactures’ visibility/present weather sensors, the OWI-430 does not require periodic field calibration for unattended field operation.
9. OSi’s advanced artificial intelligence algorithms automatically compensate for dust, water droplets and ice/snow accumulated on the lenses, ensuring reliable measurements even when the optics are partially obscured.
10. The OWI-430 requires less maintenance and offers higher reliability than any other manufacturers’ visibility/present weather sensor.
11. The sensor’s calculated MTBF (Mean Time Between Failure) is well in excess of 80,000 hours. Field based statistics significantly exceed that number.
12. The OWI-430 has reserved I/O capability built in. Extra analog, digital and serial channels are available. Other sensors may be added without requiring a separate data acquisition system. This capability allows complete automated weather stations to be implemented without requiring a separate data acquisition system. This reduces costs to customer and improves system reliability. This system integration capability is not available from any other manufacturers.