Improved VAD horizontal wind retrievals using high-altitude airborne Doppler radar

The technology presents an on-board estimation, navigation and control architecture for multi-rotor drones flying in an urban environment. It consists of adaptive algorithms to estimate the vehicle's aerodynamic drag coefficients with respect to still air and urban wind components along the flight trajectory, with guaranteed fast and reliable convergence to the true values. Navigation algorithms generate feasible trajectories between given way-points that take into account the estimated wind. Control algorithms track the generated trajectories as long as the vehicle retains a sufficient number of functioning rotors that are capable of compensating for the estimated wind. The technology provides a method of measuring wind profiles on a drone using existing motion sensors, like the inertial measurement unit (IMU), rate gyroscope, etc., that are observably necessary for any drone to operate. The algorithms are used to estimate wind around the drone. They can be used for stability or trajectory calculations, and are adaptable for use with any UAV regardless of the knowledge of weight and inertia. They further provide real-time calculations without additional sensors. The estimation method is implemented using onboard computing power. It rapidly converges to true values, is computationally inexpensive, and does not require any specific hardware or specific vehicle maneuvers for the convergence. All components of this on-board system are computationally effective and are intended for a real time implementation. The method's software is developed in a Matlab/Simulink environment, and has executable versions, which are suitable for majority of existing onboard controllers. The algorithms were tested in simulations.

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.

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.

This innovative kite system is called the WindiWing, and utilizes aerodynamic forces and moments to control its configuration for both ascent and descent, eliminating the need for an external power source or human intervention. By harnessing wind power, the system autonomously climbs and descends along a pilot kite line, provided sufficient wind conditions exist. Windiwing includes a set of stops at predetermined upper and lower bounds of the kite line, which define the highest and lowest points the WindiWing can travel. When a stop is hit, the WindiWing changes direction. Therefore, it can sustain extended flight times at different altitudes. Unlike prior solutions, WindiWing is a passive line-climber operating entirely through aero-mechanical principles and does not require electrical power or active control systems for changes in lift. Instead, WindiWing continuously moves between the designated stops along the kite tether, maintaining stable and predictable movement without the need for remote operation or onboard power. WindiWing is designed with flexibility in mind, offering the ability to carry a range of instrumentation, making it suitable for integration with kite-based systems, tethered balloons, or uncrewed aircraft platforms. The absence of electrical components reduces complexity, enhances reliability, and allows for extended atmospheric data collection with minimal oversight. By offering a scalable, cost-effective, and power-independent solution, this technology enables long-duration atmospheric profiling at various altitudes, making it an ideal tool for researchers in the fields of atmospheric research, environmental research, and education.

The electrical transmission lines used to transmit power are optimized for 50 to 60 Hz waveforms, but are suitable for waveforms of higher frequencies, into the megahertz range. Therefore, powerline conductors are capable of transmitting signals which could be used for geolocation. Indeed, frequencies in the 100 kHz range are used for diagnostic purposes in contemporary power grids today. Signals transmitted in this band are used to verify the operation of sites along the power grid, are used to configure the power grid (for example, throw a circuit breaker). The technology takes advantage of the suitability of electrical conductors employed in power transmission for signal transmission in the sub-megahertz range, and, in the preferred embodiment, utilizes the existing diagnostics signals in this range for geolocation.