SEARCH · Search NASA

Results for “phase calibration”

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.

SourceResearch connectionFrom yearThrough year

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 379 records · Page 21

All sources NASA NTRS DOE OSTI

DOE OSTI2025

Realization and Calibration of Continuously Parameterized Two-Qubit Gates on a Trapped-Ion Quantum Processor

Continuously parameterized two-qubit gates are a key feature of state-of-the-art trapped-ion quantum processors, as they have favorable error scalings and show distinct improvements in circuit performance over more restricted maximally entangling gatesets. In this work, we provide a comprehensive and pedagogical discussion on how to practically implement these continuously parameterized Mølmer–Sørensen gates on the Quantum Scientific Computing Open User Testbed, a low-level trapped-ion processor. To generate the arbitrary entangling angles, θ, we simply scale the amplitude of light used to generate the entanglement. However, doing so requires careful consideration of amplifier saturation as well as the variable light shifts that result. As such, we describe a method to calibrate and cancel the dominant fourth-order effects, followed by a dynamic virtual phase advance during the gate to cancel any residual light shifts, and find a linear scaling between θ and the residual light shift. Once we have considered and calibrated these effects, we demonstrate performance improvement with decreasing θ. Finally, we describe nuances of hardware control to transform the XX-type interaction of the arbitrary-angle Mølmer–Sørensen gate into a phase-agnostic and crosstalk-mitigating ZZ interaction.

Yale, Christopher Gordon [Sandia National Laborato↗

NASA NTRS1984

Relationship between phase difference and coefficient of restitution during low velocity foreign object transverse damage of composite plates

This work discusses a model to correlate the coefficient of restitution of low velocity transverse impacts of graphite-epoxy laminates with the residual deformation or central deflection at the end of the impact event. It is assumed that the energy absorbed by the target can be calibrated in terms of residual deflection, and thereby in terms of phase difference between the occurrence of impact force and central deflection to their maximas. Analysis was modeled on the basis of the experience from impact tests. Predictions are compared with the test results of impacted circular and flat plates. Experimentally measured values of coefficient of restitution and phase difference agreed well with the predicted relationship between them.

Lal, K. M.↗

NASA NTRS2016

Soil Moisture Active Passive Mission L4_C Data Product Assessment (Version 2 Validated Release)

The SMAP satellite was successfully launched January 31st 2015, and began acquiring Earth observation data following in-orbit sensor calibration. Global data products derived from the SMAP L-band microwave measurements include Level 1 calibrated and geolocated radiometric brightness temperatures, Level 23 surface soil moisture and freezethaw geophysical retrievals mapped to a fixed Earth grid, and model enhanced Level 4 data products for surface to root zone soil moisture and terrestrial carbon (CO2) fluxes. The post-launch SMAP mission CalVal Phase had two primary objectives for each science product team: 1) calibrate, verify, and improve the performance of the science algorithms, and 2) validate accuracies of the science data products as specified in the L1 science requirements. This report provides analysis and assessment of the SMAP Level 4 Carbon (L4_C) product pertaining to the validated release. The L4_C validated product release effectively replaces an earlier L4_C beta-product release (Kimball et al. 2015). The validated release described in this report incorporates a longer data record and benefits from algorithm and CalVal refinements acquired during the SMAP post-launch CalVal intensive period. The SMAP L4_C algorithms utilize a terrestrial carbon flux model informed by SMAP soil moisture inputs along with optical remote sensing (e.g. MODIS) vegetation indices and other ancillary biophysical data to estimate global daily net ecosystem CO2 exchange (NEE) and component carbon fluxes for vegetation gross primary production (GPP) and ecosystem respiration (Reco). Other L4_C product elements include surface (10 cm depth) soil organic carbon (SOC) stocks and associated environmental constraints to these processes, including soil moisture and landscape freeze/thaw (FT) controls on GPP and respiration (Kimball et al. 2012). The L4_C product encapsulates SMAP carbon cycle science objectives by: 1) providing a direct link between terrestrial carbon fluxes and underlying FT and soil moisture constraints to these processes, 2) documenting primary connections between terrestrial water, energy and carbon cycles, and 3) improving understanding of terrestrial carbon sink activity in northern ecosystems. There are no L1 science requirements for the L4_C product; however self-imposed requirements have been established focusing on NEE as the primary product field for validation, and on demonstrating L4_C accuracy and success in meeting product science requirements (Jackson et al. 2012). The other L4_C product fields also have strong utility for carbon science applications; however, analysis of these other fields is considered secondary relative to primary validation activities focusing on NEE. The L4_C targeted accuracy requirements are to meet or exceed a mean unbiased accuracy (ubRMSE) for NEE of 1.6 g C/sq m/d or 30 g C/sq m/yr, emphasizing northern (45N) boreal and arctic ecosystems; this is similar to the estimated accuracy level of in situ tower eddy covariance measurement-based observations (Baldocchi 2008).

Cal/Val↗

NASA NTRS2004

Real-Time Point Positioning Performance Evaluation of Single-Frequency Receivers Using NASA's Global Differential GPS System

This paper evaluates the performance of a single-frequency receiver using the 1-Hz differential corrections as provided by NASA's global differential GPS system. While the dual-frequency user has the ability to eliminate the ionosphere error by taking a linear combination of observables, the single-frequency user must remove or calibrate this error by other means. To remove the ionosphere error we take advantage of the fact that the magnitude of the group delay in range observable and the carrier phase advance have the same magnitude but are opposite in sign. A way to calibrate this error is to use a real-time database of grid points computed by JPL's RTI (Real-Time Ionosphere) software. In both cases we evaluate the positional accuracy of a kinematic carrier phase based point positioning method on a global extent.

internet-based global differential GPS (IGDG)↗

NASA NTRS1993

Test-Signal Generator For SNR Calibration

Assembly of commercial and custom-made electronic equipment designed to generate noisy intermediate-frequency or baseband received phase-modulation data-communication signals with accurately known signal-to-noise ratios. Signals used to perform signal-to-noise-ratio calibrations and other tests of responses of data-communication receivers to noisy incoming signals. Underlying principle applicable to generation of test signals for other advanced data-communication receivers.

Gutierrez-Luaces, Benito O.↗

NASA NTRS1973

The minitrack tracking function description, volume 1

The treatment of tracking data by the Minitrack system is described from the transmission of the nominal 136-MHz radio beacon energy from a satellite and the reception of this signal by the interferometer network through the ultimate derivation of the direction cosines (the angular coordinates of the vector from the tracking station to the spacecraft) as a function of time. Descriptions of some of the lesser-known functions operating on the system, such as the computer preprocessing program, are included. A large part of the report is devoted to the preprocessor, which provides for the data compression, smoothing, calibration correction, and ambiguity resolution of the raw interferometer phase tracking measurements teletyped from each of the worldwide Minitrack tracking stations to the central computer facility at Goddard Space Flight Center. An extensive bibliography of Minitrack hardware and theory is presented.

Englar, T. S., Jr.↗

NASA NTRS1981

An interferometer-based phase control system

A system for focusing and pointing the SPS power beam is discussed. The system is ground based and closed loop. One receiving antenna is required on earth. A conventional uplinked data channel transmits an 8-bit phase error correction back to the SPS for sequential calibration of each power module. Beam pointing resolution is better than 140 meters at the rectenna.

Ott, J. H.↗

NASA NTRS1980

An interferometer-based phase control system

A system for focusing and pointing the SPS power beam is discussed. The system is ground based and closed loop. One receiving antenna is required on Earth. A conventional uplink data channel transmits an 8-bit phase error correlation back to the SPS for sequential calibration of each power module. Beam pointing resolution is better than 140 meters at the Rectenna.

Ott, J. H.↗

NASA NTRS1980

An interferometer based phase control system

An interferometer based phase control system for focusing and pointing the solar power satellite (SPS) power beam is discussed. The system is ground based and closed loop. One receiving antenna is required on Earth. A conventional uplink data channel transmits an 8 bit phase error correction back to the SPS for sequential calibration of each power module. Beam pointing resolution is better than 140 meters at the rectenna.

Ott, J. H.↗

NASA NTRS1992

Radio and optical interferometric imaging

Since diffraction-limited imaging with a single aperture yields angular resolution approx. lambda/D, the attainment of high angular resolution with single apertures requires the construction of correspondingly large monolithic apertures, the whole surface of which must be figured to much less than a wavelength. At the longer wavelengths, it is impossible to build a sufficiently large single aperture: for example, at lambda 21 cm, arcsec resolution requires an aperture of diameter approx. 50 km. At the shorter wavelengths, the atmosphere imposes a natural limit in resolution of about one arcsec. However, another route is possible; that is, using synthetic apertures to image the sky. Synthetic apertures are now in use in many fields, e.g., radio interferometry, radar imaging, and magnetic-resonance imaging. Radio-interferometric techniques developed in radio astronomy over the past 40 years are now being applied to optical and IR astronomical imaging by a number of groups. Furthermore, the problem of figuring synthetic apertures is considerably simpler, and can be implemented in a computer: new 'self-calibration' techniques allow imaging even in the presence of phase errors due to the atmosphere.

Cornwell, Tim J.↗

NASA NTRS1994

Controller for the Electronically Scanned Thinned Array Radiometer (ESTAR) instrument

A prototype controller for the ESTAR (electronically scanned thinned array radiometer) instrument has been designed and tested. It manages the operation of the digital data subsystem (DDS) and its communication with the Small Explorer data system (SEDS). Among the data processing tasks that it coordinates are FEM data acquisition, noise removal, phase alignment and correlation. Its control functions include instrument calibration and testing of two critical subsystems, the output data formatter and Walsh function generator. It is implemented in a Xilinx XC3064PC84-100 field programmable gate array (FPGA) and has a maximum clocking frequency of 10 MHz.

Zomberg, Brian G.↗

NASA NTRS1996

Low Gravity Guidance System for Airborne Microgravity Research

Microgravity research techniques have been established to achieve a greater understanding of the role of gravity in the fundamentals of a variety of physical phenomena and material processing. One technique in use at the NASA Lewis Research Center involves flying Keplarian trajectories with a modified Lear Jet and DC-9 aircraft to achieve a highly accurate Microgravity environment by neutralizing accelerations in all three axis of the aircraft. The Low Gravity Guidance System (LGGS) assists the pilot and copilot in flying the trajectories by displaying the aircraft acceleration data in a graphical display format. The Low Gravity Guidance System is a microprocessor based system that acquires and displays the aircraft acceleration information. This information is presented using an electroluminescent display mounted over the pilot's instrument panel. The pilot can select the Microgravity range that is required for a given research event. This paper describes the characteristics, design, calibration and testing of the Low Gravity Guidance System Phase 3, significant lessons from earlier systems and the developmental work on future systems.

Rieke, W. J.↗

NASA NTRS2004

Scanning Tunneling Optical Resonance Microscopy Developed

The ability to determine the in situ optoelectronic properties of semiconductor materials has become especially important as the size of device architectures has decreased and the development of complex microsystems has increased. Scanning Tunneling Optical Resonance Microscopy, or STORM, can interrogate the optical bandgap as a function of its position within a semiconductor micro-structure. This technique uses a tunable solidstate titanium-sapphire laser whose output is "chopped" using a spatial light modulator and is coupled by a fiber-optic connector to a scanning tunneling microscope in order to illuminate the tip-sample junction. The photoenhanced portion of the tunneling current is spectroscopically measured using a lock-in technique. The capabilities of this technique were verified using semiconductor microstructure calibration standards that were grown by organometallic vapor-phase epitaxy. Bandgaps characterized by STORM measurements were found to be in good agreement with the bulk values determined by transmission spectroscopy and photoluminescence and with the theoretical values that were based on x-ray diffraction results.

Bailey, Sheila G.↗

NASA NTRS2011

MPS Editor

Previously, it was time-consuming to hand-edit data and then set up simulation runs to find the effect and impact of the input data on a spacecraft. MPS Editor provides the user the capability to create/edit/update models and sequences, and immediately try them out using what appears to the user as one piece of software. MPS Editor provides an integrated sequencing environment for users. It provides them with software that can be utilized during development as well as actual operations. In addition, it provides them with a single, consistent, user friendly interface. MPS Editor uses the Eclipse Rich Client Platform to provide an environment that can be tailored to specific missions. It provides the capability to create and edit, and includes an Activity Dictionary to build the simulation spacecraft models, build and edit sequences of commands, and model the effects of those commands on the spacecraft. MPS Editor is written in Java using the Eclipse Rich Client Platform. It is currently built with four perspectives: the Activity Dictionary Perspective, the Project Adaptation Perspective, the Sequence Building Perspective, and the Sequence Modeling Perspective. Each perspective performs a given task. If a mission doesn't require that task, the unneeded perspective is not added to that project's delivery. In the Activity Dictionary Perspective, the user builds the project-specific activities, observations, calibrations, etc. Typically, this is used during the development phases of the mission, although it can be used later to make changes and updates to the Project Activity Dictionary. In the Adaptation Perspective, the user creates the spacecraft models such as power, data store, etc. Again, this is typically used during development, but will be used to update or add models of the spacecraft. The Sequence Building Perspective allows the user to create a sequence of activities or commands that go to the spacecraft. It provides a simulation of the activities and commands that have been created.

Mathews, William S.↗

DOE OSTI2020

Analysis of 83m Kr prompt scintillation signals in the PIXeY detector

Prompt scintillation signals from 83m Kr calibration sources are a useful metric to calibrate the spatial variation of light collection efficiency and electric field magnitude of a two phase liquid-gas xenon time projection chamber. Because 83m Kr decays in two steps, there are two prompt scintillation pulses for each calibration event, denoted S1a and S1b. We study the ratio of S1b to S1a signal sizes in the Particle Identification in Xenon at Yale (PIXeY) experiment and its dependence on the time separation between the two signals (Δ t), notably its increase at low Δ t. Finally, in PIXeY data, the Δ t dependence of S1b/S1a is observed to exhibit two exponential components: one with a time constant of 0.05 ± 0.02 μ s, which can be attributed to processing effects and pulse overlap and one with a time constant of 10.2 ± 2.2 μs that increases in amplitude with electric drift field, the origin of which is not yet understood.

47 OTHER INSTRUMENTATION↗

NASA NTRS1998

Broadband Interferometer for Measuring Transmitted Wavefronts of Optical Bandpass Filters for HST (ACS)

The transmitted wavefronts of optical filters for the Hubble Space Telescope (HST) Advanced Camera for Surveys (ACS) are characterized using the Wildly and Openly Modified Broadband Achromatic Twyman Green (WOMBAT) Interferometer developed in the NASA/GSFC Optics Branch's Diffraction Grating Evaluation Facility (DGEF). Because only four of thirty-three of ACS's optical bandpass filters transmit the 633 nm light of most commercial interferometers, a broadband interferometer is required to verify specified transmitted wavefront of ACS filters. WOMBAT's design is a hybrid of the BAT interferometer developed by JPL used for HST Wide Field and Planetary Camera 2 (WFPC-2) filters and a WYKO 400 phase shifting interferometer. It includes a broadband light source, monochromator, off-axis, parabolic collimating and camera mirrors, an aluminum-coated fused silica beam splitter, flat retroreflecting mirrors for the test and reference arms, and a LTV-sensitive CCD camera. An outboarded, piezo-electric phase shifter holds the flat mirror in the interferometer's reference arm. The interferometer is calibrated through interaction between the WYKO system's software and WONMAT hardware for the test wavelength of light entering the beam splitter. Phase-shifted interferograms of the filter mounted in the test arm are analyzed using WYKO's Vision' software. Filters as large as 90 mm in diameter have been measured over a wavelength range from 200 to 1100 nm with a sensitivity of lambda/200 rms at lambda = 633 nm. Results of transmitted wavefront measurements are shown for ACS fixed band pass and spatially-variable bandpass filters for a variety of wavelengths.

Boucarut, R. A.↗

NASA NTRS1977

A digital goniometer for VOR

A new VOR (VHF omni-range) goniometer design which promises to improve the reliability and maintainability of the VOR ground station is described. The heart of the new concept is the use of two digital phase shifters to produce the rotating figure-of-eight pattern of conventional VOR. Using digital circuits, the goniometer adjustments and calibration reduce to timing adjustments of binary signals. A common clock used for timing the digital phase shifters also synchronizes the 30 Hz modulation of the 9.96 kHz reference.

Meer, S. A.↗

DOE OSTI2023

An improved synthetic signal injection routine for the Haloscope At Yale Sensitive To Axion Cold dark matter (HAYSTAC)

Microwave cavity haloscopes are among the most sensitive direct detection experiments searching for dark matter axions via their coupling to photons. When the power of the expected microwave signal due to axion–photon conversion is on the order of 10 −24 W, having the ability to validate the detector response and analysis procedure by injecting realistic synthetic axion signals becomes helpful. Here, we present a method based on frequency hopping spread spectrum for synthesizing axion signals in a microwave cavity haloscope experiment. It allows us to generate a narrow and asymmetric shape in frequency space that mimics an axion’s spectral distribution, which is derived from a Maxwell–Boltzmann distribution. In addition, we show that the synthetic axion’s power can be calibrated with reference to the system noise. Further, compared to the synthetic axion injection in the Haloscope At Yale Sensitive to Axion Cold dark matter (HAYSTAC) Phase I, we demonstrated synthetic signal injection with a more realistic line shape and calibrated power.

47 OTHER INSTRUMENTATION↗