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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 433 records · Page 24

Method to Measure Total Noise Temperature of a Wireless Receiver During Operation

An electromagnetic signal receiver and methods for determining the noise level and signal power in a signal of interest while the receiver is operating. In some embodiments, the signal of interest is a GPS signal. The receiver includes a noise source that provides a noise signal of known power during intervals while the signal of interest is observed. By measuring a signal-to-noise ratio for the signal of interest and the noise power in the signal of interest, the noise level and signal power of the signal of interest can be computed. Various methods of making the measurements and computing the power of the signal of interest are described. Applications of the system and method are described.

Young, Lawrence E.↗

Three-Phase LCC-LCC Compensated 50-kW Wireless Charging System with Non-Zero Interphase Coupling

In this paper, an LCC-LCC compensated 50 kW 3phase (3φ) wireless charging system with nonzero interphase mutual inductance is demonstrated. The 3φ-LCC compensation is designed considering a nonzero mutual-inductance among the phase-coils to meet resonance criteria, balance voltages and currents of the resonant tank components, achieve desired voltage gain, and ensure the zero-voltage switching (ZVS) operation. An experimental prototype of the 3φ-LCC-LCC compensation circuit is built for a 50 kW bipolar coil-based 3φ wireless charging system. The prototype system was tested at rated 50 kW power for evaluating the efficiency, ZVS operation, electric and magnetic field emissions, and thermal characteristics. The experimental results show 94.3% dc-to-dc efficiency and only 4.4 μT rms magnetic field emission at the rated 50 kW output power.

Mohammad, Mostak↗

Secondary-Side Active Rectifier Synchronization and Control in LCC-LC Compensated Inductive Power Transfer Systems

This paper proposes a communication-less synchronization and output power control strategy for LCC-LC compensated inductive power transfer systems with a secondaryside active rectifier. By replacing the passive rectifier with an active bridge, the proposed architecture eliminates the need for a separate secondary-side DC-DC converter and enables direct regulation of battery power. The key challenge in such a system is achieving robust synchronization of the secondary active bridge with the primary inverter without access to primary-side signals. To address this issue, the secondary-side variables are analyzed and the current through the secondary series inductor is identified as a load-independent synchronization variable with a fixed phase relationship to the primary excitation. A fixed-frequency second order generalized (SOGI)-based phase locked loop (PLL) is used to estimate the switching phase and frequency, and a phase-shift-based output power controller is developed using a phasor-transformer model of the active bridges. A modified control formulation is further introduced to remove phase-dependent loop-gain variation and simplify controller design. Simulation results validate the proposed method under both fixed and varying switching-frequency conditions, demonstrating successful frequency tracking from 82 kHz to 88 kHz and accurate output power regulation over a wide operating range. The proposed method offers a compact and effective solution for high-power IPT systems by enabling secondary-side synchronization and control without wireless communication or an additional DC-DC conversion stage.

Fernandes, Arnold Anthony [ORNL] (ORCID:0009000631↗

A Harmonics Interferometric Doppler Sensor With a Neon Lamp Detector

A cost-effective harmonic interferometric Doppler sensor has been developed to obtain both amplitude and phase of the micro-Doppler signatures of moving objects. A phase chopper is used to generate the harmonics of the interferometry signal. For cost-effectiveness, a Gunn diode source is used for signal generation and a neon lamp is employed as a broadband detector. An advanced signal processing algorithm has been developed to extract both amplitude and phase Doppler signatures. A prototype has been built to demonstrate the effectiveness of the harmonic interferometric Doppler sensor at 35 GHz, with Doppler objects such as human hand and metal objects. In addition, the broadband detection capability of the neon lamp allows the Doppler sensor to work up to the millimeter-wave regime and potentially beyond the terahertz (THz) wave regime. Due to the ruggedness of the neon lamp detector, it is expected that the Doppler sensor has important applications of sensing and wireless communication in harsh environment such as high-temperature, high-power and radioactive conditions.

Doppler sensor↗

Review and Gap Analysis of Heliostat Components and Controls

This investigation provides a comprehensive literature review pertaining to heliostat components and controls as part of the U.S. Department of Energy (DOE), Heliostat Consortium (Heliocon) program. Here, this work presents a detailed assessment of subcomponents, controls and wireless communications elements that comprise various designs of helisotats within concentrating solar power (CSP) installations. Additionally, this work also provides the results of an industry survey, intended to compliment the literature discussion, to provide a gap analysis of the primary technology and cost areas that need to be addressed to help improved to spur concentrating solar power (CSP) bankability. Although the results of the study determined several key areas for development, three strategic areas identified were: (1) the use of advanced composite materials to replace a need for expensive steel within the structure and mirror substrate, (2) employment of closed-loop controls for automated calibration, reduction of commissioning time and O&M hours, reduction of drive requirements, as well as overall cost reduction, and (3) the need for more Heliostat-centric codes and standards to facilitate engineering confidence in the development of new features, cost reductions, or other design iterations to be seamlessly introduced without optical performance problems.

14 SOLAR ENERGY↗

Deployable Fresnel Rings

Deployable Fresnel rings (DFRs) significantly enhance the realizable gain of an antenna. This innovation is intended to be used in combination with another antenna element, as the DFR itself acts as a focusing or microwave lens element for a primary antenna. This method is completely passive, and is also completely wireless in that it requires neither a cable, nor a connector from the antenna port of the primary antenna to the DFR. The technology improves upon the previous NASA technology called a Tri-Sector Deployable Array Antenna in at least three critical aspects. In contrast to the previous technology, this innovation requires no connector, cable, or other physical interface to the primary communication radio or sensor device. The achievable improvement in terms of antenna gain is significantly higher than has been achieved with the previous technology. Also, where previous embodiments of the Tri-Sector antenna have been constructed with combinations of conventional (e.g., printed circuit board) and conductive fabric materials, this innovation is realized using only conductive and non-conductive fabric (i.e., "e-textile") materials, with the possible exception of a spring-like deployment ring. Conceptually, a DFR operates by canceling the out-of-phase radiation at a plane by insertion of a conducting ring or rings of a specific size and distance from the source antenna, defined by Fresnel zones. Design of DFRs follow similar procedures to those outlined for conventional Fresnel zone rings. Gain enhancement using a single ring is verified experimentally and through computational simulation. The experimental test setup involves a microstrip patch antenna that is directly behind a single-ring DFR and is radiating towards a second microstrip patch antenna. The first patch antenna and DFR are shown. At 2.42 GHz, the DFR improves the transmit antenna gain by 8.6 dB, as shown in Figure 2, relative to the wireless link without the DFR. A figure illustrates the relative strength of power coupling between the first and second microstrip antennas with and without the DFR. Typically, a DFR is designed for use at a particular frequency; however, testing of a DFR indicated a relatively wide operational bandwidth of approximately 8.2%. Wider bandwidth operation and multi-band operation are anticipated by extending the known art of conventional Fresnel rings to the DFRs. Increasing the number of rings used to construct a DFR antenna increases the gain, with the upper bound limited often by the largest practical dimensions that can be tolerated for a given application. The maximum theoretical improvement in gain for a single ring is 9.5 dB. Experimental results are within 0.9 dB of this theoretical value. Adding rings increases gain, and theoretically, improvements of 10 to 13 dB above that of the primary antenna gain can be achieved with two- and three-ring versions.

Kennedy, Timothy F.↗

Biomedical Wireless Ambulatory Crew Monitor

A compact, ambulatory biometric data acquisition system has been developed for space and commercial terrestrial use. BioWATCH (Bio medical Wireless and Ambulatory Telemetry for Crew Health) acquires signals from biomedical sensors using acquisition modules attached to a common data and power bus. Several slots allow the user to configure the unit by inserting sensor-specific modules. The data are then sent real-time from the unit over any commercially implemented wireless network including 802.11b/g, WCDMA, 3G. This system has a distributed computing hierarchy and has a common data controller on each sensor module. This allows for the modularity of the device along with the tailored ability to control the cards using a relatively small master processor. The distributed nature of this system affords the modularity, size, and power consumption that betters the current state of the art in medical ambulatory data acquisition. A new company was created to market this technology.

Chmiel, Alan↗

A Field-Deployable Wireless Data Acquisition System for Ground-Test Arrays

This paper describes the development, characterization, and deployment of a field-deployable wireless data acquisition system for ground-test arrays, applicable in noise-source localization or beamforming measurements such as those encountered during airframe noise flyover measurement tests. The system design is enabled by commercially available, low-power Internet of Things (IoT) processors and Wi-Fi communication components. Time is synchronized across the array wirelessly by leveraging the Coordinated Universal Time (UTC) time provided by the Global Positioning System (GPS). Initial laboratory characterization of the system demonstrated its ability to meet acoustic bandwidth, dynamic range, time synchronization, environmental, and battery life requirements for typical ground-test array deployments. A successful system deployment at NASA Langley was performed that included measurement of a suspended elevated static noise source, and Uncrewed Aerial System (UAS) vehicle measurements using a quadcopter operated both in hover mode and forward flight. Beamform analysis of the acquired data showed an excellent ability of the array to extract accurate sound pressure levels from the suspended source. Synchronization of the array and vehicle GPS timecodes allowed the ability to extract acoustic signatures from the UAS vehicle during hover and forward flight maneuvers over the array. These results validate that the use of a high channel count wireless array is advantageous in airframe and propulsion noise flyover test campaigns.

wireless↗

Wireless Sensor Instrumentation for Distributed Sensing in Ground-Test Facilities

Wireless sensors have a number of advantages over wired sensors for flexible or temporary diagnostic deployment in a field or lab setting. Relative to wireless alternatives, traditional wired systems encounter limitations including spatial and weight constraints, maintenance costs, and signal integrity in high-noise environments. Ground-test facilities often face these challenges and cause increase down-time costs and failure of data integrity. This paper describes the development and implementation of flexible wireless sensor boards for applications within ground-test facilities using different network architectures. These boards implement state-of-the- art STM32 microprocessor chips for high-speed data acquisition and computational power. Additionally, the design integrates long-range radio transceivers with power output of +20dBm, easily reaching 2 km range, while maintaining high interference immunity and minimizing current consumption. The wireless sensor boards were implemented to demonstrate performance through benchmark testing and by taking distributed electrically-isolated measurements on a high-voltage lab apparatus while using different network architectures. Although this test case is in a laboratory setting, this network architecture could be easily repurposed for various other forms of monitoring.

Wireless Sensor Network↗

Interference from the Robledo DSN Transmitters to Central Madrid IMT-2000/UMTS System through Terrain Diffraction at S-Band

This study evaluates the possible interference from DSN Robledo 70-m transmitter with Madrid IMT-2000/UMTS wireless users in Spain as both systems will share the same frequency band. Using the effective earth radius, the 50 km terrain profile between Robledo and Madrid is modified and reconstructed. The diffraction propagation losses due to mountain peaks are calculated for the receivers in Madrid urban area. The mountains along the path are simplified into a rounded knife-edge and a rounded obstacle. The results show that for a near surface receiver (1.5 m above the ground) in Madrid, interference signal powers received are less than -135 dBm, which is far below the -109 dBm, the IMT-2000 wireless phone threshold. When a receiver is located at about 40 m above the ground (e.g., the top of Clock Tower of Cibeles Palace), diffraction will generate interference power less than -115 dBm. We find that our calculation results are basically consistent with those from the Longley-Rice model, while the latter has smaller loss because of the low resolution terrain profile used. As a comparison, we also find that the measurements of interference powers of -121.2 dBm at the top of Clock tower is in the range of the estimation. We conclude that the interference through the diffraction mechanism will not cause any problem to IMT-2000/UMTS users at near the surface of Madrid urban area.

telecommunications↗

Real-Time Wireless Data Acquisition System

Current and future aerospace requirements demand the creation of a new breed of sensing devices, with emphasis on reduced weight, power consumption, and physical size. This new generation of sensors must possess a high degree of intelligence to provide critical data efficiently and in real-time. Intelligence will include self-calibration, self-health assessment, and pre-processing of raw data at the sensor level. Most of these features are already incorporated in the Wireless Sensors Network (SensorNet(TradeMark)), developed by the Instrumentation Group at Kennedy Space Center (KSC). A system based on the SensorNet(TradeMark) architecture consists of data collection point(s) called Central Stations (CS) and intelligent sensors called Remote Stations (RS) where one or more CSs can be accommodated depending on the specific application. The CS's major function is to establish communications with the Remote Stations and to poll each RS for data and health information. The CS also collects, stores and distributes these data to the appropriate systems requiring the information. The system has the ability to perform point-to-point, multi-point and relay mode communications with an autonomous self-diagnosis of each communications link. Upon detection of a communication failure, the system automatically reconfigures to establish new communication paths. These communication paths are automatically and autonomously selected as the best paths by the system based on the existing operating environment. The data acquisition system currently under development at KSC consists of the SensorNet(TradeMark) wireless sensors as the remote stations and the central station called the Radio Frequency Health Node (RFHN). The RFF1N is the central station which remotely communicates with the SensorNet(TradeMark) sensors to control them and to receive data. The system's salient feature is the ability to provide deterministic sensor data with accurate time stamps for both time critical and non-time critical applications. Current wireless standards such as Zigbee(TradeMark) and Bluetooth(Registered TradeMark) do not have these capabilities and can not meet the needs that are provided by the SensorNet technology. Additionally, the system has the ability to automatically reconfigure the wireless communication link to a secondary frequency if interference is encountered and can autonomously search for a sensor that was perceived to be lost using the relay capabilities of the sensors and the secondary frequency. The RFHN and the SensorNet designs are based on modular architectures that allow for future increases in capability and the ability to expand or upgrade with relative ease. The RFHN and SensorNet sensors .can also perform data processing which forms a distributed processing architecture allowing the system to pass along information rather than just sending "raw data points" to the next higher level system. With a relatively small size, weight and power consumption, this system has the potential for both spacecraft and aircraft applications as well as ground applications that require time critical data.

Valencia, Emilio J.↗

Wearable Wireless Telemetry System for Implantable Bio-MEMS Sensors

In this paper, a telemetry and contact-less powering system consisting of an implantable bio-MEMS sensor with a miniature printed square spiral chip antenna and an external wearable garment with printed loop antenna is investigated. The wearable garment pick-up antenna and the implantable chip antenna are in close proximity to each other and hence couple inductively through their near-fields and behave as the primary and the secondary circuits of a transformer, respectively. The numerical and experimental results are graphically presented, and include the design parameter values as a function of the geometry, the relative RF magnetic near-field intensity as a function of the distance and angle, and the current density on the strip conductors, for the implantable chip antenna.

Simons, Rainee N.↗

Material aspects of giga-Hertz ZnO TFTs for wireless systems

Abstract Having enabled high-value application capabilities through mass production of flat-panel displays, X-ray imagers, and solar panels, Large-Area Electronics (LAE) holds potential to open new frontiers in wireless applications for the Internet of Things and 5G/6G, by enabling unprecedented spatial control and power efficiency through large size and flexible form factor of radiative apertures. However, this requires boosting operation frequencies from the traditional limits in the range of 10–100’s of mega-Hertz to multi giga-Hertz. In this paper, we discuss critical device metrics, to characterize zinc-oxide (ZnO) thin-film transistor (TFT) operation frequency for both active (for signal amplification) and passive components in LAE-based circuits and systems. We then describe the key structural and material approaches towards recently demonstrated LAE-based giga-Hertz wireless systems employing ZnO TFTs. Bringing LAE to the giga-Hertz regime provides a path towards flexible and meter-scale monolithic integrated wireless systems. Graphical abstract

Ma, Yue (ORCID:0000000186724090)↗

Physiological Signal Conditioner

Sensors 2000! is developing a Physiological Signal Conditioner (PSC) for monitoring of astronauts in the ISS Human Research Facility. The PSC is battery powered and worn by the crew. The Engineering Development Unit (PSC EDU) and the form-and-fit PSC Tooling Model will be displayed along with associated graphics and text explanations. Results of a recent advanced PSC-2 feasibility study will be presented. The presentation will stimulate discussion of the functional capabilities of a wireless, crew worn Physiological Signal Conditioner. Application of advanced technology to meet the conflicting demands of size, power, and functional capability will be of interest.

Friedericks, C.↗

Radio Relays Improve Wireless Products

Signal Hill, California-based XCOM Wireless Inc. developed radio frequency micromachine (RF MEMS) relays with a Phase II Small Business Innovation Research (SBIR) contract through NASA?s Jet Propulsion Laboratory. In order to improve satellite communication systems, XCOM produced wireless RF MEMS relays and tunable capacitors that use metal-to-metal contact and have the potential to outperform most semiconductor technologies while using less power. These relays are used in high-frequency test equipment and instrumentation, where increased speed can mean significant cost savings. Applications now also include mainstream wireless applications and greatly improved tactical radios.

Source record↗

Lunar Surface Network Relay Terminal: A Lunar Communications Platform

This paper will discuss the development of a Lunar Surface Relay that will serve as a central terminal for lunar surface wireless communications (e.g., 3GPP, Wi-Fi) for surface assets to transmit and receive data back-and-forth with Earth through lunar orbital relays or direct with Earth. Four variations of a wireless surface terminal were designed with varying concepts of operation to assess mass, power, cost drivers, and trade-offs. The designs entailed one stationary platform and three mobile which provided interesting trade-offs. The terminals are powered for operation with either a radioisotope/battery power system or solar array/battery power system.

WiFi↗

VLSI design of turbo decoder for integrated communication system on a chip applications

A high-throughput low-power turbo decoder core has been developed for integrated communication system applications such as satellite communications, wireless LAN, digital TV, cable modem, Digital Video Broadcast (DVB), and xDSL systems. The turbo decoder is based on convolutional constituent codes, which outperform all other Forward Error Correction techniques. This turbo decoder core is parameterizable and can be modified easily to fit any size for advanced communication system-on-chip products. The turbo decoder core provides Forward Error Correction of up to 15 Mbits/sec on a 0.13-micron CMOS FPGA prototyping chip at a power of 0.1 watts.

turbo decoder↗