OSI – Scintillometry for Air/Gas Flow Measurement

Building on over 30 years of ground-breaking research, with NASA, NOAA, U.S. Army, and Air Force, Optical Scientific, Inc. (OSI) has developed a world-wide reputation for accuracy and rugged reliability. OSI‘s product line of advanced optical sensors, present weather sensors, and AWOS systems are recognized as leaders in the global market  /

In 1981 Dr. Ting-I Wang, working at the NOAA ERL Wave Propagation Laboratory published a seminal paper: Wind Measurements By Temporal Cross-Correlation Of Optical Scintillations showing how this method could be used to measure changes in air flow just by analyzing the movement of air through a beam of light. Other papers refining this approach soon followed, along with grant of original US patents.

In 1985, OSI was formed to develop and apply this concept to the collection of weather data. This small core company located in the I-270 high-technology corridor outside Washington, DC, soon began producing weather instruments of unprecedented accuracy and reliability. From simple Optical Rain Gauges (ORG) to Long-baseline Optical Anemometer (LOA) which can measure air movement over a distance of up to 10 kilometers.

These instruments found a variety of uses in atmospheric data reporting for NASA, NOAA, US Army, US Air Force, along with Sandia and Argonne National Laboratories. State, local governments and commercial ventures also put the sensors to work at airports, along highways, in shipboard and industrial applications, where they are still in service today.

In 1999, OSI developed the OFS 2000 Optical Flow Sensor. A refinement and miniaturization of the LOA technology, this tough, dependable, highly-accurate air/gas flow sensor - tested and verified at NIST (National Institute of Standards and Technology) - became the premier flow sensor for industries concerned with limiting greenhouse gas emissions, or simply seeking more efficient process control. OFS ruggedness, flexibility and precision quickly established it as the leader in air/gas flow measurement. In the years since then, OSI has responded to customer needs by developing ever more sophisticated versions with wider capabilities.

OFS 2000 optical flow sensors transmit a light beam from one side of a flow area to another. The scintillation caused by the passage of air or gas through the entire light beam is detected, analyzed, and the velocity calculated using an adaptive algorithm refined with over 20 years of field data and constant analysis. This mode of measurement is immune to the effects of temperature, moisture content, particulate count, or pressure.

OFS 2000

Our original optical flow sensor. Widely used wherever combustion emission compliance or process control are critical.

OFS 2000W

For applications where light can be obscured by particulate. System automatically compensates for variations in opacity.

OFS 2000F

Designed specifically for applications where accurate tracking of dynamic change is critical. –F model measures velocity of 0.3 to 100 m/s – both directions.


Extended range with AGC to optimize the amount of light based on the steam level. Measurement is not dependent on differential pressure, design DP, beta ratio, temperature, gas composition, humidity or the speed of sound.

A partial list of OFS advantages:

OFS 2000 flow sensors require no calibration – ever. Observable drift is less than 1% per year. An automatic calibration check feature and continuous self-test diagnostics are built-in for user security.

The sensor heads are isolated from the flow media. Measurement is completely non-interfering.

OFS can install in tight spaces with minimum space requirements of 2 upstream / 1 downstream diameters. Installation is to standard ANSI pattern 4” pipe flange.

OFS 2000 can be configured with the ability to accept smart temperature and pressure sensor current loop data to calculate and report volumetric flow or mass flow in addition to velocity.

OFS 2000 sensors meet or exceed:

●  EPA Method 14

●  EPA MACT RSR 40 CFR 63.670

●  EPA 40 CFR part 60 & 75

●  EPA 40 CFR part 60 sub part J & Ja

●  SCAQMD rule 1118

Along with development of new sensors, OSI has followed a policy of careful, continuous refinement to existing products, and exploration of new avenues. With the continuing success of our scientific research, sensors, systems, and technology, OSI has been able to expand its market globally and now supports customers in North and South America, Europe, the Middle East, Africa, India, China, and Australia.

Our progress has been due to our constant effort to meet our customer’s needs: military, scientific, civil, commercial or industrial. We take pride in our history of original research, innovative thinking, supporting our customers, and - simply making the best products we can.

contact information

If you care to learn more about how our technology can be tailored, or if you have a special requirement, we are ready to help.

Optical Scientific Inc.

2 Metropolitan Court

Suite 6

Gaithersburg, MD 20878

T  +01 301 963 3630
F  +01 301 948 4674
W  opticalscientific.com