MétaCan
Menu
Back to cohort
Record W2155788466 · doi:10.1063/1.1581396

High-frequency direction finding in space

2003· article· en· W2155788466 on OpenAlexaff
H. G. James

Bibliographic record

VenueReview of Scientific Instruments · 2003
Typearticle
Languageen
FieldPhysics and Astronomy
TopicIonosphere and magnetosphere dynamics
Canadian institutionsCommunications Research Centre Canada
Fundersnot available
KeywordsPhysicsDipoleDipole antennaAmplitudeRadiation patternAntenna (radio)Computational physicsPlane waveAcousticsReciprocity (cultural anthropology)Magnetic dipoleOpticsTelecommunicationsComputer science

Abstract

fetched live from OpenAlex

Transionospheric propagation experiments at high frequency (HF) are planned in the Enhanced Polar Outflow Probe small-satellite mission. Crossed dipoles connected to a HF receiver in the spacecraft will be used to measure parameters of incident waves originating from coordinated ground transmitters. This article is concerned with the measurement of one important wave parameter: its direction of arrival (DOA). Two important issues about the receiving antenna signals are addressed here: the effective length of the dipoles, and the computational method of determining the DOA from the amplitudes and relative phase of signals. The electric field radiated by the monopole elements composing the dipoles has been calculated using the NEC4 code. With recourse to the reciprocity principle that the effective length of the active dipole equals that of the same dipole as a receiving antenna, the dependence of the effective length on DOA has been computed, for various antenna-spacecraft configurations. For 3 m monopoles combined as dipoles, and for frequencies between 5 and 18 MHz, effective lengths can be well approximated using a simple expression for a short dipole, with modest adjustment to include asymmetries of the transmitting members. The radiation-reception patterns of isolated monopoles are quite symmetric, implying that the experiment does not depend critically on dipole signals. The antenna models provide a basis for the numerical technique for inverting the amplitude and phase of voltages induced by an plane wave incident on crossed dipoles to the DOA of the wave. The procedure assumes a cw elliptically polarized wave, taking account of plasma effects. The mathematics leads to expressions for the induced dipole voltages as functions of the wave vector azimuthal and polar angles. The inverse determination of the DOA angles is underspecified for only two dipoles, and requires selecting the true solution from two or more possible azimuth-polar pairs throughout the 4π sr solid-angle space surrounding the spacecraft. The selection of the solution will be guided by values expected for the known ground-transmitter and satellite positions, and by other wave parameter measurements.

Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.

How this classification was reachedexpand

Full frame distilled prediction

Teacher imitation

Not calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.

metaresearch head score (Codex)0.000
metaresearch head score (Gemma)0.000
Version: codex-gemma-dda1882f352aValidation status: machine_predicted_unvalidated
Candidate categoriesInsufficient payload (model declined to judge)
Consensus categoriesnone
DomainCandidate signal: none · Consensus signal: none
Study designCandidate signal: Theoretical or conceptual · Consensus signal: none
GenreCandidate signal: Empirical · Consensus signal: Empirical
Teacher disagreement score0.491
Threshold uncertainty score0.999

Codex and Gemma teacher scores by category

CategoryCodexGemma
Metaresearch0.0000.000
Meta-epidemiology (narrow)0.0000.000
Meta-epidemiology (broad)0.0000.000
Bibliometrics0.0000.001
Science and technology studies0.0000.000
Scholarly communication0.0000.000
Open science0.0000.000
Research integrity0.0000.000
Insufficient payload (model declined to judge)0.0020.000

Machine scores (provisional)

The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.

Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.

Opus teacher head0.009
GPT teacher head0.243
Teacher spread0.233 · how far apart the two teachers sit on this one work
Validation statusscore_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from it

Classification

machine, unvalidated

Machine predicted; a candidate call from one teacher head, not a consensus.

Study designTheoretical or conceptual
Domainnot available
GenreEmpirical

How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".

Quick stats

Citations15
Published2003
Admission routes1
Has abstractyes

Explore more

Same venueReview of Scientific InstrumentsSame topicIonosphere and magnetosphere dynamicsFrench-language works237,207