Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “Radio frequency”

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.

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

At least 901 records · Page 50
All sourcesNASA NTRSDOE OSTI
DOE OSTI2025

Precision gyroscope from the helicity of light

We describe a gyroscope that measures rotation based on the effects of the rotation on the polarization of light. Rotation induces a differential phase shift in the propagation of left- and right-circularly polarized light and this phase shift can be measured in suitably designed interferometric setups. The signal in this setup is independent of the frequency of light, unlike various sources of noise such as vibrations, which cause phase shifts that depend on the frequency. Such vibrations are the practical limit on the sensitivity of conventional Sagnac-style optical interferometers that are typically used as gyroscopes. In the proposed setup, one can potentially mitigate this source of noise by simultaneously using two (or more) sources of light that have different frequencies. The signal in this setup scales with the total storage time of the light. Due to its frequency independence, it is thus most optimal to measure the signal using superconducting radio-frequency systems where the high finesse of the available cavities enables considerably longer storage times than is possible in an optical setup.

47 OTHER INSTRUMENTATION↗
NASA NTRS1985

Waves In Space Plasmas (WISP)

Waves in space plasmas (WISP) utilizes powerful radio transmitters and sensitive receivers to probe the secrets of the magnetosphere, ionosphere and atmosphere. The scientific objective is to achieve a better understanding of the physical processes occurring in these regions. For example, audio frequency radio waves will be radiated from the long WISP antenna, will travel to the outer reaches of the magnetosphere, and will interact with Van Allen belt particles, releasing some of their energy which amplifies the waves. Study of this interaction will give us a better understanding of a major magnetospheric process, wave particle interactions. Radio waves from WISP at higher frequencies (AM radio and beyond) will be reflected by the ionosphere and will, for example, advance our understanding of bubbles in the equatorial ionosphere which affect satellite communications.

Taylor, W. W. L.↗
NASA NTRS1986

Waves In Space Plasmas (WISP)

Waves in space plasmas (WISP) utilizes powerful radio transmitters and sensitive receivers to probe the secrets of the magnetosphere, ionosphere and atmosphere. The scientific objective is to achieve a better understanding of the physical processes occurring in these regions. For example, audio frequency radio waves will be radiated from the long WISP antenna, will travel to the outer reaches of the magnetosphere, and will interact with Van Allen belt particles, releasing some of their energy which amplifies the waves. Study of this interaction will give a better understanding of a major magnetospheric process, wave-particle interactions. Radio waves from WISP at higher frequencies (AM radio and beyond) will be reflected by the ionosphere and will, for example, advance our understanding of bubbles in the equatorial ionosphere which affect satellite communications.

Taylor, W. W. L.↗
NASA NTRS2021

The Sun Radio Interferometer Space Experiment (SunRISE) Mission

The Sun Radio Interferometer Space Experiment (SunRISE) will provide an entirely new view on particle acceleration and transport in the inner heliosphere by creating the first low radio frequency interferometer in space to localize heliospheric radio emissions. By imaging and determining the location of decametric-hectometric (DH) radio bursts from 0.1 MHz–25 MHz, SunRISE will provide key information on particle acceleration mechanisms associated with coronal mass ejections (CMEs) and the magnetic field topology from active regions into interplanetary space. Six small spacecraft, of a 6U form factor, will fly in a supersynchronous geosynchronous Earth orbit (GEO) orbit within about 10 km of each other, in a passive formation, and image the Sun in a portion of the spectrum that is blocked by the ionosphere and cannot be observed from Earth. Key aspects that enable this mission are that only position knowledge of the spacecraft is required, not active control, and that the architecture involves a modest amount of on-board processing coupled with significant ground-based processing for navigation, position determination, and science operations. Mission-enabling advances in software-defined radios, GPS navigation and timing, and small spacecraft technologies, developed and flown on the DARPA High Frequency Research (DHFR), the Community Initiative for Continuing Earth Radio Occultation (CICERO), and the Mars Cube One (MarCO) missions, have made this mission affordable and low-risk. The SunRISE mission will involve utilizing commercial access to space, in which the SunRISE spacecraft will be carried to their target orbit as a secondary payload in conjunction with a larger host spacecraft intended for GEO.

Neilson, Tim↗
NASA NTRS2022

The Sun Radio Interferometer Space Experiment (SunRISE) Mission

The Sun Radio Interferometer Space Experiment (SunRISE) will provide an entirely new view on particle acceleration and transport in the inner heliosphere by creating the first low radio frequency interferometer in space to localize heliospheric radio emissions. By imaging and determining the location of decametric-hectometric (DH, 0.1 MHz–23 MHz) solar radio bursts, SunRISE will provide key information on particle acceleration mechanisms associated with coronal mass ejections (CMEs) and the magnetic field topology from active regions into interplanetary space. The SunRISE Observatory will consist of six space vehicles in a passive formation, in orbits designed to keep them within approximately 10 km of each other, and flying in a supersynchronous geosynchronous Earth orbit (GEO). Each space vehicle consists of a Solar DH-GNSS payload and a 6U form factor spacecraft. The SunRISE Observatory together with significant ground-based processing, will enable imaging of the Sun in a portion of the spectrum that is blocked by the ionosphere and cannot be observed from Earth. Key aspects that enable this mission are that only position knowledge of the space vehicles is required, not active control, and that the architecture involves a modest amount of on-board processing coupled with significant ground-based processing for navigation, position determination, and science operations. Mission-enabling advances in software-defined radios, GPS navigation and timing, and small spacecraft technologies, developed and flown on the DARPA High Frequency Research (DHFR) and the Community Initiative for Continuing Earth Radio Occultation (CICERO) have made this mission affordable and low-risk. The SunRISE mission will exploit the multiple spacecraft per aperture (MSPA) capability of NASA’s Deep Space Network (DSN), for more efficient data transfers of larger data volumes, and utilize commercial access to space, in which the SunRISE space vehicles will be carried to their target orbit as secondary payloads in conjunction with a larger host spacecraft intended for GEO.

Neilson, Tim↗
NASA NTRS2016

Development of RFI Mitigation Techniques with Digital Beamforming

Remote sensing radars with longer wavelengths penetrate deeper into the observed scene and are more suitable for the scientific observation of ice sheets or vegetation. Therefore, SAR systems are moving to lower frequencies like L- or P-band. However, as the frequency spectrum is a limited resource, this means that the occupied frequency band has to be shared with existing users. These users can have serious impact on the imaging quality. Radio frequency interference (RFI) that arrives at the antenna together with the SAR backscatter is causing a drop of the signal-to-noise ratio. Despite the high processing gain of the SAR signal, artifacts can appear in the image if the RFI is strong enough. This can lead to a corruption of the acquired data and make it unsuitable for scientific purposes. Hence, the investigation of methods for RFI mitigation is critical to the performance of radar missions and to ensure they meet their main task.

Digital Beamforming↗
NASA NTRS1992

New results on the radio-far-infrared relation for galaxies

The radio-FIR relation has been decomposed into thermal bremsstrahlung-FIR and synchrotron-FIR relation for a sample of 31 galaxies. Both radio emission components are tightly correlated with the FIR emission for early and late-type spiral as well as irregular galaxies. It follows that any mixture of the radio components produces a tight universal radio-FIR relation. At high radio frequencies, thermal bremsstrahlung can dominate the radio emission over a large range of luminosities so that the slope of the radio-FIR relation approaches that of the thermal bremsstrahlung-FIR relation and is therefore close to unity (0.97 +/- 0.02). At lower frequencies, synchrotron emission dominates and the slope approaches that of the synchrotron-FIR ratio which is significantly steeper than unity (1.33 +/- 0.10). The results are consistent with a scenario in which the FIR luminosities of galaxies scale in direct proportion to the star formation rate.

Price, Rob↗