In the late 1990’s wind turbines with nacelle heights exceeding 60 meters were introduced to the wind energy community. Initially, wind prospecting and siting studies continued to use 50-meter wind towers and extrapolate the measurement to the nacelle heights. It was quickly determined that this approach was not sufficient for the placement of these tall turbines. The next approach was to increase the wind tower heights to between 80 meters and 100 meters. In this case the initial financial investment (100 meter towers, installation, etc.), the required FAA permits and tower safety equipment, the increased need for larger land areas coupled with the visibility of these towers in the local community area are reasons to seek alternative measurement methods.
In the mid-1990’s, Atmospheric Systems Corporation (ASC) independently developed an acoustic remote sensing unit called a Doppler miniSoDAR (or miniSoDAR for short) for high-resolution wind profiling in the lowest 200 meters of the atmosphere. Initially the miniSoDAR was developed under a NAVY SBIR (Small Business Innovative Research) grant to provide wind measurements with NAVY helicopters hovering at a height of 100 feet (AGL) at a distance of 150 feet away from the miniSoDAR system. The miniSoDAR systems were designed to be autonomous and telemeter their data continuously to a central Control and Display PC near the helicopter Field Operations Director. The miniSoDAR was specifically designed for providing high spatial resolution measurements in high background noise environments. SODAR technology was originally designed and employed in high altitude wind measurements (600 meters or higher) and low background noise environments (characteristic of the Air Quality and Atmospheric Research monitoring sites). The miniSoDAR was (and remains) a significant technical advance to SODAR technology. In contrast to those commercial systems designed for Air Quality applications the miniSoDAR can produce wind profile measurements (from 15 meters to 200 meters in 5 meter increments) in time intervals as short as 30 seconds to hour averages or longer.
Since its introduction the miniSoDAR has been successfully used in a wide range of observational and operational activities. For example, NASA together with the USAF has purchased thirteen miniSoDAR systems to support their rocket launch and Space Shuttle landing activities at Cape Canaveral and Vandenburg Air Force Base. These units have been operational for over four years and are networked (via an ethernet link) to their respective base weather operations office. In effect the miniSoDAR systems are in the process of replacing the local wind tower network. The FAA has recently realized the potential for the miniSoDAR to detect and monitor airplane wing tip wake vortices. ASC is currently contracted to provide the instrumentation and data processing expertise to rapidly advance the wing tip wake detection program.
In addition to developing and manufacturing the miniSoDAR hardware, ASC also has developed user friendly Windows based programs to manipulate and visualize the miniSoDAR data. These programs provide our customer’s with the ability to cost effectively use miniSoDAR measurements.
On the application of miniSoDAR technology to wind energy