Synchronization of Weak Indoor GPS Signals with Doppler Using a Segmented Matched Filter and Accumulation
Bibliographic record
Abstract
This paper investigates GPS codephase acquisition with very low SNR signals found within large buildings. Conventional GPS receivers can acquire the GPS codephase relatively easily when in direct line of sight with the satellites. However, acquisition becomes difficult with highly attenuated signals found inside buildings. Recent government regulations aim to improve 911 service for wireless telephones by supplying dispatchers with caller location, however, this requires the development of new technologies. With extensive signal averaging, GPS signals can provide positioning within large buildings. We assume 5dB/floor of signal attenuation so the GPS signal would be -183 dBWor less at the bottom of a 5-story building. We assume 2 MHz system bandwidth and surrounding walls at room temperature of 290 K (17degC) so the Boltzmann noise is -141 dBW. More than 50 dB SNR improvement is provided by an accumulating segmented matched filter that is robust to polarity reversals caused by Doppler frequency offset and by GPS data transitions. Through simulation, performance comparisons are made to a conventional matched filter (CMF) operating without polarity reversals.
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How this classification was reachedexpand
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 | 0.000 |
| 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 teacher head, 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".