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NASA NTRS2003

Wireless Phone Threat Assessment and New Wireless Technology Concerns for Aircraft Navigation Radios

To address the concern for cellular phone electromagnetic interference to aircraft radios, a radiated emission measurement process was developed for two dominant digital standards of wireless handsets. Spurious radiated emissions were efficiently characterized from devices tested in either a semi-anechoic or reverberation chamber, in terms of effective radiated power. Eight representative handsets (four from each digital standard) were commanded to operate while varying their radio transmitter parameters (power, modulation, etc.). This report provides a detailed description of the measurement process and resulting data, which may subsequently be used by others as a basis of consistent evaluation of other portable transmitters using a variety of wireless transmission protocols. Aircraft interference path loss and navigation radio interference threshold data from numerous reference documents, standards, and NASA partnerships were compiled. Using these data, a preliminary risk assessment is provided for wireless phone interference to aircraft Localizer, Glideslope, Very High Frequency Omni directional Range, and Global Positioning Satellite radio receivers on typical transport airplanes. The report identifies where existing data for device emissions, interference path loss, and navigation radio interference thresholds need to be extended for an accurate risk assessment for wireless transmitters in aircraft.

Ely, Jay J.↗

NASA NTRS1979

Voyager 1 Planetary Radio Astronomy Observations Near Jupiter

Results are reported from the first low frequency radio receiver to be transported into the Jupiter magnetosphere. Dramatic new information was obtained both because Voyager was near or in Jupiter's radio emission sources and also because it was outside the relatively dense solar wind plasma of the inner solar system. Extensive radio arcs, from above 30 MHz to about 1 MHz, occurred in patterns correlated with planetary longitude. A newly discovered kilometric wavelength radio source may relate to the plasma torus near Io's orbit. In situ wave resonances near closest approach define an electron density profile along the Voyager trajectory and form the basis for a map of the torus. Studies in progress are outlined briefly.

Warwick, J. W.↗

NASA NTRS1979

Voyager 1 planetary radio astronomy observations near Jupiter

Results from the first low-frequency radio receiver to be transported into the Jupiter magnetosphere are reported. Dramatic new information was obtained, both because Voyager was near or in Jupiter's radio emission sources and because it was outside the relatively dense solar wind plasma of the inner solar system. Extensive radio spectral arcs, from above 30 to about 1 MHz, occurred in patterns correlated with planetary longitude. A newly discovered kilometric wavelength radio source may relate to the plasma torus near Io's orbit. In situ wave resonances near closest approach define an electron density profile along the Voyager trajectory and form the basis for a map of the torus. Detailed studies are in progress and are outlined briefly.

Warwick, J. W.↗

NASA NTRS2003

Graphical and Statistical Analysis of Airplane Passenger Cabin RF Coupling Paths to Avionics

Jafri, Madiha↗

NASA NTRS2005

Comparative Analysis of Interference Pathloss Coupling Patterns on B-737 VS. B757 Airplanes

Portable wireless technology provides many benefits to modern day travelers. Over the years however, numerous reports have cited portable electronic devices (PEDs) as a possible cause of electromagnetic interference (EMI) to aircraft navigation and communication radio systems. PEDs may act as transmitters, both intentional and unintentional, and their signals may be detected by the various radio receiver antennas installed on the aircraft. Measurement of the radiated field coupling between passenger cabin locations and aircraft communication and navigation receivers, via their antennas is defined herein as interference path loss (IPL). IPL data is required for assessing the threat of PEDs to aircraft radios, and is very dependent upon airplane size, the interfering transmitter position within the airplane, and the location of the particular antenna for the aircraft system of concern. NASA Langley Research Center, Eagles Wings Inc., and United Airlines personnel performed extensive IPL measurements on several Boeing 737 airplanes. In the Spring of 2004, extensive IPL measurements were also taken on several Boeing 757 airplanes under a cooperative agreement between NASA Langley Research Center and Delta Airlines. The objective of this paper is to analyze IPL measurement data, to better understand the impact on coupling levels based on the different locations of the aircraft radio antennas on B-757 and B-737 airplanes, and to provide a basis for future fuzzy logic modeling of airplane IPL. This effort will build upon previous fuzzy modeling of IPL data for B-737 airplane data.

Jafri, Madiha↗

NASA NTRS2007

Small Aircraft RF Interference Path Loss Measurements

Interference to aircraft radio receivers is an increasing concern as more portable electronic devices are allowed onboard. Interference signals are attenuated as they propagate from inside the cabin to aircraft radio antennas mounted on the outside of the aircraft. The attenuation level is referred to as the interference path loss (IPL) value. Significant published IPL data exists for transport and regional category airplanes. This report fills a void by providing data for small business/corporate and general aviation aircraft. In this effort, IPL measurements are performed on ten small aircraft of different designs and manufacturers. Multiple radio systems are addressed. Along with the typical worst-case coupling values, statistical distributions are also reported that could lead to more meaningful interference risk assessment.

Nguyen, Truong X.↗

NASA NTRS2007

Small Aircraft RF Interference Path Loss

Nguyen, Truong X.↗

NASA NTRS1995

Kilometric type 3 radio bursts observed from high southern ecliptic latitudes by Ulysses

The Ulysses URAP experiment has provided the first measurements of remote and in-situ wave phenomena from high southern latitudes. Remote sensing of type 3 solar radio bursts constitute an important component of the Ulysses observations. Type 3 radio emissions, which have never before been viewed from outside the ecplitic plane, have been observed by Ulysses to its maximum southern latitude (approximately 80 deg S), although their frequency of occurrence has generally diminished due to the declining phase of the solar cycle. In addition, the Ulysses radio receiver measures both the direction of arrival and the complete polarization state of incident radiation. These physical parameters provide information on the origin and nature of the radio emission. Preliminary analyses have indicated that kilometric type 3 radiation is often approximately 10-20% circularly polarized at the highest URAP frequencies. New directional information provides crucial information on the effects of beaming and scattering of the radiation in the interplanetary medium.

Reiner, M. J.↗

NASA NTRS1977

Interaction of electromagnetic and acoustic waves in a stochastic atmosphere

This paper considers the interaction of electromagnetic and acoustic waves where a Radio Acoustic Sounding System (RASS) is operated in a stochastic environment characterized by turbulence, winds and mean-temperature gradients. It has been shown that for a RASS operating at acoustic frequencies below a few kilohertz propagating under typical atmospheric conditions, turbulence has little effect on the strength of the received radio signal scattered from the pulse at heights up to a few kilometers. This result implies that the received RF signal level (power) is primarily a function of sound intensity which decreases as x exp minus 2 where x is the altitude.

Bhatnagar, N.↗

NASA NTRS2001

Relationship between Jovian Hectometric Attenuation Lanes And Io Volcanic Activity

Within the Galileo plasma wave instrument data a narrow (in frequency) attenuation band is seen in the hectometric (HOM) emission that varies in frequency with system III longitude. This attenuation lane is believed to be the result of near-grazing incidence or coherent scattering of radio emission near the outer edge of the Io torus, i.e., when the ray path is nearly tangent to an L shell containing the Io flux tube. Such a process should, therefore, be enhanced when the Io volcanic activity is increased and the Io flux tube has enhanced density. We have performed a systematic study of the existing Galileo radio emission data in an effort to determine the phenomenology and frequency of occurrence of the attenuation lanes and the association, if any, with published volcanic activity of Io. Our results indicate that the attenuation lanes are present almost all of the time but are enhanced on occasion. The best examples of attenuation lanes occur when Galileo is within approximately 65 R(sub J) of Jupiter and thus are probably more apparent because of the increased signal-to-noise ratio of the radio receivers. The lack of continuous monitoring of Io activity and the lack of known activity on the anti-Earthward side of Io are problematic and make detailed correlation with radio emission very difficult at this time. Nevertheless, if the data are displayed for periods when the spacecraft is within 65 R(sub J) (i.e., for each perijove pass), then the highest-contrast lanes occur on most passes when the Io volcanic activity is also high for that pass. These results support our current understanding of attenuation lane formation and suggest that future efforts can be made to better understand the interaction of HOM emission with the Io flux tube.

Menietti, J. D.↗

NASA NTRS2002

Ultrawideband Electromagnetic Interference to Aircraft Radios: Results of Limited Functional Testing With United Airlines and Eagles Wings Incorporated, in Victorville, California

On February 14, 2002, the FCC adopted a FIRST REPORT AND ORDER, released it on April 22, 2002, and on May 16, 2002 published in the Federal Register a Final Rule, permitting marketing and operation of new products incorporating UWB technology. Wireless product developers are working to rapidly bring this versatile, powerful and expectedly inexpensive technology into numerous consumer wireless devices. Past studies addressing the potential for passenger-carried portable electronic devices (PEDs) to interfere with aircraft electronic systems suggest that UWB transmitters may pose a significant threat to aircraft communication and navigation radio receivers. NASA, United Airlines and Eagles Wings Incorporated have performed preliminary testing that clearly shows the potential for handheld UWB transmitters to cause cockpit failure indications for the air traffic control radio beacon system (ATCRBS), blanking of aircraft on the traffic alert and collision avoidance system (TCAS) displays, and cause erratic motion and failure of instrument landing system (ILS) localizer and glideslope pointers on the pilot horizontal situation and attitude director displays. This report provides details of the preliminary testing and recommends further assessment of aircraft systems for susceptibility to UWB electromagnetic interference.

Ely, Jay J.↗

NASA NTRS2002

Ultrawideband Electromagnetic Interference to Aircraft Radios

A very recent FCC Final Rule now permits marketing and operation of new products that incorporate Ultrawideband (UWB) technology into handheld devices. Wireless product developers are working to rapidly bring this versatile, powerful and expectedly inexpensive technology into numerous consumer wireless devices. Past studies addressing the potential for passenger-carried portable electronic devices (PEDs) to interfere with aircraft electronic systems suggest that UWB transmitters may pose a significant threat to aircraft communication and navigation radio receivers. NASA, United Airlines and Eagles Wings Incorporated have performed preliminary testing that clearly shows the potential for handheld UWB transmitters to cause cockpit failure indications for the air traffic control radio beacon system (ATCRBS), blanking of aircraft on the traffic alert and collision avoidance system (TCAS) displays, and cause erratic motion and failure of instrument landing system (ILS) localizer and glideslope pointers on the pilot horizontal situation and attitude director displays. This paper provides details of the preliminary testing and recommends further assessment of aircraft systems for susceptibility to UWB electromagnetic interference.

Ely, Jay J.↗

NASA NTRS1999

A Versatile Planetary Radio Science Microreceiver

We have developed a low-power. programmable radio "microreceiver" that combines the functionality of two science instruments: a Relative Ionospheric Opacity Meter (riometer) and a swept-frequency, VTF/HF radio spectrometer. The radio receiver, calibration noise source, data acquisition and processing, and command and control functions are all contained on a single circuit board. This design is suitable for miniaturizing as a complete flight instrument. Several of the subsystems were implemented in a field-programmable gate array (FPGA), including the receiver detector, the control logic, and the data acquisition and processing blocks. Considerable efforts were made to reduce the power consumption of the instrument, and eliminate or minimize RF noise and spurious emissions generated by the receiver's digital circuitry. A prototype instrument was deployed at McMurdo Station, Antarctica, and operated in parallel with a traditional riometer instrument for approximately three weeks. The attached paper (accepted for publication by Radio Science) describes in detail the microreceiver theory of operation, performance specifications and test results.

Fry, Craig D.↗

NASA NTRS2011

Multi-Spacecraft Observations of Saturn Kilometric Radio Emission

Saturn kilometric radiation (SKR) is the auroral radio emission of Saturn, which has been observed by Voyager 1 & 2, Cassini, and Ulysses. Ulysses is able to detect the intense intervals of SKR from distances up to 10 AU, because of its long antennas (72 m tip-to-tip) and sensitive radio receivers. Studies of SKR by A. Lecacheux gave the surprising result that the periodicity of SKR varied with time; it was not locked to a planetary rotation of Saturn. This result has been confirmed by Cassini radio observations. Here, we compare Ulysses and Cassini observations of SKR to constrain a mode! for the SKR emission geometry. SpecifIcally, we examine the question - are the brighter sources of 5KR fixed in Saturn longitude or local time? The results have significant consequences for our understanding of SKR and its varying periodicity

MacDowall, R. J.↗

DOE OSTI2024

Detecting dark matter substructures on small scales with fast radio bursts

The matter power spectrum is only weakly constrained on subgalactic scales, while physics beyond the Standard Model can leave unique imprints, especially on sub-parsec scales. We propose measuring the arrival-time difference of fast radio bursts (FRBs) along two adjacent sightlines as a new probe to dark matter substructures on scales down to ∼ 1 AU . We discuss two observational scenarios in which it may be possible to place interesting constraints on such models through the monitoring of repeating FRB sources: (i) By sending radio receivers to space to form a baseline of tens of AU or more and measuring the temporal variation of the arrival-time difference between receivers. (ii) By measuring the temporal variation of the arrival-time difference between two lensed images of one strongly lensed repeater. In both scenarios, obtaining interesting constraints requires correlating the voltage time series to measure the radio signal arrival time to sub-nanosecond precision. We find that two radio dishes separated by 20 AU may be sensitive to the enhancement of small-scale structures at ∼ 10 - 8 M ⊙ masses in the QCD axion dark matter scenario, or from an early epoch of matter domination with a reheating temperature up to 60 MeV. Other dark matter models, such as those composed of ∼ 10 - 13 M ⊙ primordial black holes produced during inflation, would also be probed by this method. We further show that a strong lensing situation of multiple images provides an equivalent ∼ 2000 AU ( σ v / 10 3 km s - 1 ) ( δ t / 10 yr ) baseline, for a typical velocity of dark matter substructures σ v and an observational time span δ . This is much more sensitive, but with the uncertainty that intervening decoherence from the interstellar medium may degrade the timing precision, and that spatial variation in the FRB emission spot may result in confounding signals. We show that the lensing magnifications of Type Ia supernovae constrain a similar quantity to such FRB timing, with present limits being equivalent to ruling out the same parameter space that would be probed by a 0.14 AU baseline.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

NASA NTRS1997

Ulysses and WIND simultaneous observations of the radio emission associated with the 6-7 January 1997 coronal mass ejection

The three dimensional source location of interplanetary type 2 radio bursts is intended to be determined from two spacecraft observations, performed by the radio receivers onboard the WIND and Ulysses spacecraft and associated with the interplanetary coronal mass ejection detected by the large advanced spectrometer coronagraph (LASCO) from the SOHO spacecraft. The intensity time profiles recorded by WIND and Ulysses were compared and their directivity is found to vary from one component of radio emission to another. The three dimensional location was obtained by radio triangulation and was deduced from the direction measured at WIND and the difference of the arrival times measured at both spacecraft. The sensitivity of both determination methods to wave scattering and refraction was discussed.

Hoang, S.↗

NASA NTRS1999

U Burst in the Solar Wind

A type U bursts was observed on 22 June 1998 with the WAVES radio receivers on the Wind spacecraft. It descended in frequency from 5 MHz to the turning frequency of about 1 MHz. It is extremely rare that a U burst is observed at such a low frequency, well out in the solar wind. Using a density model to convert frequency to radial distance, we find that the radio emission started at 3 solar radius, and that the electron stream turned back toward the sun at about 8 solar radius. The probable origin of the energetic electrons was in a B 6.8 X-ray flare that was coincident with the onset of the U burst. A series of images by the SOHO/LASCO chronograph show a slow (214 km/s) CME in progress on the west limb whose front was at 9 solar radius, at the time of the U burst. As no stable magnetic loops exist at radial distances such as 8-9 solar radius, we attribute the U burst to a stream of energetic electrons accelerated in an active region at the footpoint of one leg of the expanding arch of the CME. The electron stream became unstable and began emitting radio emission at about 3 solar radius, continued to emit as it passed the top of the loop at 8-9 solar radius, then stopped emitting in the downgoing leg at about 4 solar radius.

Leblanc, Y.↗

NASA NTRS1978

Miniature interferometer terminals for earth surveying

A system of miniature radio interferometer terminals was proposed for the measurement of vector baselines with uncertainties ranging from the millimeter to the centimeter level for baseline lengths ranging, respectively, from a few to a few hundred kilometers. Each terminal would have no moving parts, could be packaged in a volume of less than 0.1 cu m, and would operate unattended. These units would receive radio signals from low-power (10 w) transmitters on earth-orbiting satellites. The baselines between units could be determined virtually instantaneously and monitored continuously as long as at least four satellites were visible simultaneously.

Counselman, C. C., III↗