Swath bathymetry and the requirement for handling multiple same-time arrivals
Bibliographic record
Abstract
Swath bathymetry sonar is used to obtain profiles of the bottom by estimating the arrival angle of the backscatter for a given range. Simple interferometric sonars estimate the angle by measuring the phase difference between two receive elements. This procedure works well if the backscatter is from a single area of the bottom and there are no competing signals. If, however, two or more signals from different directions arrive at the elements at the same time, the resulting phase difference will be in error, and hence, the estimated bottom location will be in error. This paper describes typical survey situations where multiple same-time signals are likely and provides examples from survey data. The situations discussed include shallow water applications where multipath signals and surface scattering are present, and the situation where two bottoms are present within the profile. Both towfish and pole mount deployment configurations are considered. It is concluded that a swath bathymetry system must be able to operate in the presence of at least two same-time signals, and preferably three or four. Mitigation techniques are useful for eliminating multipath and surface scatter, but multiple bottoms must be estimated simultaneously requiring the swath bathymetry system to estimate multiple angles simultaneously.
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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 | 0.001 | 0.004 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.006 | 0.003 |
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".