Interactive Sonic Boom Display
aerospace
Interactive Sonic Boom Display (DRC-TOPS-7)
Provides Pilots with Real-Time Sonic Boom Information
Overview
Engineers at NASA's Armstrong Flight Research Center have developed a Real-Time Sonic Boom Display for aircraft that enables pilots to control boom placement. The system can be integrated into a cockpit or flight control room to help pilots place loud booms in specific locations away from populated areas or prevent them from occurring. Armstrong's sonic boom display system leverages existing tools co-developed and enhanced by the U.S. Air Force and NASA to predict sonic boom propagation to the ground. The technology can be used on current-generation supersonic aircraft, which generate loud sonic booms, as well as future-generation low-boom aircraft, anticipated to be quiet enough to be flown over land.
The Technology
A supersonic shock wave forms a cone of pressurized air molecules that propagates outward in all directions and extends to the ground. Factors that influence sonic booms include aircraft weight, size, and shape, in addition to its altitude, speed, acceleration and flight path, and weather or atmospheric conditions. NASA's Real-Time Sonic Boom Display takes all these factors into account and enables pilots to control and mitigate sonic boom impacts.
How It Works
Armstrong's technology incorporates 3-dimensional (3D) Earth modeling and inputs of 3D atmospheric data. Central to the innovation is a processor that calculates significant information related to the potential for sonic booms based on an aircraft's specific operation. The processor calculates the sonic boom near a field source based on aircraft flight parameters, then ray traces the sonic boom to a ground location taking into account the near field source, environmental condition data, terrain data, and aircraft information. The processor signature ages the ray trace information to obtain a ground boom footprint and also calculates the ray trace information to obtain Mach cutoff condition altitudes and airspeeds.
Prediction data are integrated with a real-time, local-area moving-map display that is capable of displaying the aircraft's currently generated sonic boom footprint at all times. A pilot can choose from a menu of pre-programmed maneuvers such as accelerations, turns, or pushovers and the predicted sonic boom footprint for that maneuver appears on the map display. This allows pilots to select or modify a flight path or parameters to either avoid generating a sonic boom or to place the sonic boom in a specific location. The system also provides pilots with guidance on how to execute a chosen maneuver.
Why It Is Better
No other system exists to manage sonic booms in-flight. NASA's approach is unique in its ability to display in real time the location and intensity of shock waves caused by supersonic aircraft. The system allows pilots to make in-flight adjustments to control the intensity and location of sonic booms via an interactive display that can be integrated into cockpits or flight control rooms. The technology has been in use in Armstrong control rooms and simulators since 2000 and has aided several sonic boom research projects.
Aerospace companies have the technological capability to build faster aircraft for overland travel; however, the industry has not yet developed a system to support flight planning and management of sonic booms. The Real-Time Sonic Boom Display fills this need. The capabilities of this cutting-edge technology will help pave the way toward overland supersonic flight, as it is the key to ensuring that speed increases can be accomplished without disturbing population centers.
Benefits
- Works in cockpits and flight control rooms: The technology enables in-flight carpet boom predictions, control room flight planning and analysis.
- Reduces noise pollution: This tool allows appropriate placement of the boom to minimize its impact on the ground.
- Provides information in real time: The system uses real-time data, allowing pilots to respond to changes and make appropriate adjustments to minimize sonic boom exposure.
Applications
- Commercial supersonic vehicles: Companies are developing commercial aircraft that will require this kind of technology to ensure that sonic booms do not adversely affect the public.
- Federal Aviation Administration (FAA): Regulators will require this type of system to approve flight plans, monitor aircraft in flight, and review flight data
- Aerospace R&D: This system is helping NASA develop trajectories in aircraft simulators and increase test point efficiency to reduce boom noise.
|
Tags:
|
Similar Results
Application of Leading Edge Serration and Trailing Edge Foam for Undercarriage Wheel Cavity Noise Reduction
Among the tests, landing gear cavities, a known cause of airframe noise, were evaluated. These are the regions where the landing gear deploys from the main body of an aircraft, typically leaving a large cavity where airflow can get pulled in, creating noise. NASA applied two concepts to these sections, including a series of chevrons placed near the front of the cavity with a sound-absorbing foam at the trailing wall, as well as a net that stretched across the opening of the main landing gear cavity. This altered the airflow and reduced the noise resulting from the interactions between the air, the cavity walls, and its edges.
Improved Ground Collision Avoidance System
This critical safety tool can be used for a wider variety of aircraft, including general aviation, helicopters, and unmanned aerial vehicles (UAVs) while also improving performance in the fighter aircraft currently using this type of system.
Demonstrations/Testing
This improved approach to ground collision avoidance has been demonstrated on both small UAVs and a Cirrus SR22 while running the technology on a mobile device. These tests were performed to the prove feasibility of the app-based implementation of this technology. The testing also characterized the flight dynamics of the avoidance maneuvers for each platform, evaluated collision avoidance protection, and analyzed nuisance potential (i.e., the tendency to issue false warnings when the pilot does not consider ground impact to be imminent).
Armstrong's Work Toward an Automated Collision Avoidance System
Controlled flight into terrain (CFIT) remains a leading cause of fatalities in aviation, resulting in roughly 100 deaths each year in the United States alone. Although warning systems have virtually eliminated CFIT for large commercial air carriers, the problem still remains for fighter aircraft, helicopters, and GAA.
Innovations developed at NASAs Armstrong Flight Research Center are laying the foundation for a collision avoidance system that would automatically take control of an aircraft that is in danger of crashing into the ground and fly it—and the people inside—to safety. The technology relies on a navigation system to position the aircraft over a digital terrain elevation data base, algorithms to determine the potential and imminence of a collision, and an autopilot to avoid the potential collision. The system is designed not only to provide nuisance-free warnings to the pilot but also to take over when a pilot is disoriented or unable to control the aircraft.
The payoff from implementing the system, designed to operate with minimal modifications on a variety of aircraft, including military jets, UAVs, and GAA, could be billions of dollars and hundreds of lives and aircraft saved. Furthermore, the technology has the potential to be applied beyond aviation and could be adapted for use in any vehicle that has to avoid a collision threat, including aerospace satellites, automobiles, scientific research vehicles, and marine charting systems.
Statistical Audibility Prediction (SAP) Algorithm
A method for predicting the audibility of an arbitrary time-varying noise (signal) in the presence of masking noise is described in "An Algorithm for Statistical Audibility Prediction (SAP) of an Arbitrary Signal in the Presence of Noise" published in the Journal of the Audio Engineering Society (Vo. 69, No. 9, September 2021). The SAP method relies on the specific loudness, or loudness perceived through the individual auditory filters, for accurate statistical estimation of audibility vs. time. As such, this work investigated a new hypothesis that audibility is more accurately discerned within individual auditory filters by a higher-level, decision-making process. Audibility prediction vs. time is intuitive since it captures changes in audibility with time as it occurs, critical for the study of human response to noise. Concurrently, time-frequency prediction of audibility may provide valuable information about the root cause(s) for audibility useful for the design and operation of sources of noise. Empirical data, gathered under a three-alternative forced-choice (3AFC) test paradigm for low-frequency sound, has been used to examine the accuracy of SAPs.
Future work should involve additional studies to examine the performance of SAP with realistic ambient noise and signals with higher-frequency content.
Virtual Aircraft Target Generator for ADS-B Testing
The Virtual Target Generator (VTG) is a system designed to create radio frequency (RF) signals that mimic the presence of nearby aircraft, for testing satellite-based surveillance systems. The VTG works by using a GPS receiver or other position data source to calculate a virtual target position, which may be calculated by applying predefined offsets and trajectories relative to the host. These virtual positions are encoded into standard message formats, such as ADS-B, and modulated onto an RF carrier signal.
The VTG includes a calibrated signal amplifier that adjusts the signal power so only the target test aircraft receives the signal, ensuring no other aircraft are affected. The test aircraft's surveillance avionics detect and interpret these virtual targets as if they were actual aircraft, enabling full participation in the testing of traffic collision avoidance, surveillance, or display systems.
The VTG supports complex test scenarios including dynamic movement, multiple simultaneous targets, and customizable aircraft parameters such as speed, heading, and altitude. The system is fully compliant with FAA ADS-B specifications and can be installed on the test aircraft itself or on a nearby companion aircraft.
Multi-Protocol Remote Monitoring for Radio Networks
The system revolves around a Communications Remote Monitoring Panel (CRMP), which interfaces with multiple radios operating under different communication protocols. The CRMP intelligently identifies each radio’s communication specification, such as analog, digital, or proprietary protocols, and dynamically adjusts to ensure the correct protocol is used for proper communication. This capability allows for seamless interaction between otherwise incompatible systems. Once connected, the CRMP transmits queries to assess the status of each connected radio to retrieve metrics including operational status, voltage, power status, and internal temperature. The CRMP can also remotely switch radios on or off, or flag problems for maintenance crews. The system supports real-time data acquisition, cross-protocol translation, and scalable network management. Whether deployed at a single control center or across multiple geographically dispersed facilities, the system improves visibility into the health of communication networks while minimizing the need for on-site technicians. Data trends may also inform replacement equipment acquisitions. Its modular, scalable architecture enables simultaneous monitoring of multiple radios, making it ideal for expanding networks or integrating legacy and next-gen systems.
