Retrieval of Ship Radial Velocity From Single-Channel Complex-Valued Spaceborne SAR Imagery
Why this work is in the frame
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Bibliographic record
Abstract
This article proposes two different techniques to estimate the radial velocity component in complex-valued single-channel space-based synthetic aperture radar (SAR) systems for ships on the open ocean in cases where ship wakes or other features are not observable. While the first technique is based on the well-known Doppler centroid anomaly detection method developed for improved SAR processing, the second novel technique exploits the difference between the azimuth or Doppler ambiguities on either side of the ship image caused by a radial motion. Measuring either the ambiguity shift or the intensity ratio and comparing it with the theoretically expected values permits inferring an estimate of the radial velocity component. Estimation results for both techniques are compared with the Cramér–Rao bound (CRB) and the accurate benchmark estimator along-track interferometric (ATI). Although not as accurate as ATI, it is demonstrated that useful velocity information can be deduced, which is currently not available on almost all existing space-based SAR systems.
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Full frame distilled prediction
Teacher imitationNot 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.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
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.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from it