Space-Domain Awareness Using Over-the-Horizon Radar
Bibliographic record
Abstract
The use of existing over-the-horizon radar (OTHR) systems as space-domain awareness (SDA) sensors is experimentally evaluated by tracking several International Space Station (ISS) passes under different solar activity conditions. Using range and Doppler measurements, a single-frequency ionospheric correction technique is introduced and is shown to be critical to the implementation of accurate SDA using OTHR. This single-frequency technique is also useful for monitoring the ionosphere total electron content (TEC) using a space target without very accurate prior knowledge of its orbital parameters. All measurements and orbit determination results are validated with truth data provided by the National Aeronautics and Space Administration (NASA). Although it is determined that angle-of-arrival (AOA) measurements are not accurate enough for accurate SDA, orbit determination using single-pass observations from a single site are shown to yield position and velocity errors that can be better than 500 m and 0.7 m/s with a radar bandwidth of only 10 kHz. Accurate SDA using OTHR is determined to be possible especially at night or in periods of solar minimum.
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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 | 0.000 | 0.001 |
| 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 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| 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 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".