3 - Précision de mesure des sonars bathymétriques en fonction du rapport signal/bruit
Bibliographic record
Abstract
Multibeam echosounders and bathymetric side-scan sonars are nowadays widely used for seafloor topographic mapping. Depending on the measurement angle sector and on the sonar array structure, various methods are usable to estimate time-angle pairs needed to estimate sounding point positions. Distinctions are to be made between methods based on signal amplitude or phase, on one hand, and measurements at given time or angle, on the other hand; this leads to define four main methods, covering most of bathymetry systems available today (maximum amplitude instant, phase difference direction, zero-phase difference instant, maximum amplitude direction). The principles of these four approaches are described, and their respective measurement accuracy is evaluated as a function of the signal-to-noise ratio value. The formulae developed here account for the array geometry and beamforming weighting. The performances of two current methods for oblique incidences are compared and commented. The particular case of measurements close to the vertical is discussed. The performances of elementary measurements of phase, time and angle for fluctuating signals are presented in an appendix.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.003 | 0.007 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.002 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.004 | 0.004 |
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.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
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".