Wind Event Warning System

Langley has developed various technologies to enable the portable detection system, including: - 3-inch electret condenser microphone - unprecedented sensitivity of -45 dB/Hz - compact nonporous windscreen - suitable for replacing spatially demanding soaker hoses in current use - infrasonic calibrator for field use - piston phone with a test signal of 110 dB at 14Hz. - laboratory calibration apparatus - to very low frequencies - vacuum isolation vessel - sufficiently anechoic to permit measurement of background noise in microphones at frequencies down to a few Hz - mobile source for reference - a Helmholtz resonator that provides pure tone at 19 Hz The NASA system uses a three-element array in the field to locate sources of infrasound and their direction. This information has been correlated with PIREPs available in real time via the Internet, with 10 examples of good correlation.

The Vortex Radiometer (VR) creates concentric, annular antenna beam patterns that measure sky-noise temperature. Annular antenna patterns are created by imparting orbital angular momentum into the electric field received by the antenna using spiral phase plates placed in front of the antenna aperture, generating multiple radiometer channels. Data points are then collected by plotting the measured noise temperature of each radiometer channel as a function of time. Noise temperature increases as a noise source (e.g., weather-related noise, signal interference, etc.) traverses the antenna beam patterns. An algorithm is then used to correlate noise temperature peaks in adjacent beams and to determine when a fade will occur, how long the fade will last, and how intense the fade will be. With this information, effective and efficient strategies can be implemented using cognitive communication and antenna systems to autonomously select the optimum fade-mitigation technique and parameter (e.g., increasing the transmission power, adjusting the modulation and/or coding scheme, etc.). NASA's VR system has been prototyped, including the radiometer device and the algorithm for characterizing noise sources based on VR data. Simulations have shown that a VR system can instruct an existing cognitive antenna to switch between Ka- and X-Band communications in order to avert interference from small diameter noise sources. Any high-performance communication systems operating in RF or optical frequencies may benefit from NASA's VR capabilities.

Radiosondes are launched twice a day from different locations of the world and meteorological data is collected to plot the STUV diagram and determining CAPE (Cumulative Average Potential Energy) values. Radiosondes are not re-usable and used only at pre-determined locations around the globe. Moreover, a radiosonde can drift up to 125 miles from its release point. About 75,000 radiosondes are used every year. Given this unmet need, an inventor at NASA has developed an advanced airborne meteorological system which can provide meteorological parameters at any location at any desired time. In additional to routinely used meteorological sensors, an infrasonic sensor is also included to determine wind shear at local and regional levels. The airborne system may also be used in towns and cities to track drones and UAVs in the area. The airborne vehicle (UAV or drone) should be able to track seismic waves, magnetic storms, magneto-hydrodynamic waves, tornadoes, meteor, and lightning, etc. This technology can be use to measure environmental turbulence including wind shear, vortices as well as large and small eddies is an important factor in forecasting local and regional weather. It can also detect infrasound at ranges of many miles from the source and the shape of the acoustic power spectrum can be used to identify type of turbulence in the atmosphere.

This technology utilizes the U.S. high-voltage power transmission grid system as an extremely large antenna to extract unprecedented spatiotemporal space physical and geological information from distributed GIC observations. GICs are measured using differential a magnetometer technique involving one fluxgate magnetometer under the transmission line and another reference magnetometer station nearby. The reference station allows subtraction of the natural field from the line measurement, leaving only the GIC-related Biot-Savart field. This allows inversion of the GIC amplitude. The magnetometer stations are designed to operate autonomously. They are low-cost, enabling large scale application with a large number of measurement locations.

This technology comprises a novel system of detecting, inspecting and analyzing a corona discharge using an ultra-violet camera. It is useful for a number of potential applications, most notably, power line fault detection. The most novel feature is that it uses UV instead of IR which has been problematical for corona discharge detection because there is too much interference from other sources. UV detection offers images that isolate the location of the corona discharge with far greater precision.