gps_time_offset
from the skyGPS-reported UTC minus the local clock
Time spoofing, receiver faults
The assembly that notices when the sky goes dark
यं वै सूर्यं स्वर्भानुस्तमसाविध्यदासुरः ।
अत्रयस्तमन्वविन्दन्नह्यन्ये अशक्नुवन् ॥
The sun, whom the Asura Svarbhānu had enveloped with darkness, the Atris recovered; no others were able.
Rig Veda 5.40.9
In hymn 5.40 the sky's most trusted reference goes dark — the eclipse of Svarbhānu — and is understood rather than merely feared. The fifth Mandala of the Rigveda is called the Atri Mandala.
Sangam (சங்கம்) is confluence and assembly: rivers meeting, and the classical Tamil academies where independent voices reached consensus by collective judgment. That is the architecture — a sangam of independent channels deliberating over what the sky and the clocks are really saying.
GPS is infrastructure that almost everything else quietly depends on, and it is easy to attack. Jamming drowns the signal. Spoofing is worse: the receiver keeps reporting a confident fix, and the fix is a lie. Both are cheap. Neither announces itself.
The defence is not a better receiver — it is a second opinion that does not come from the same sky. Atri Sangam's premise is that a site which already knows where it is can check what it is being told.
Each channel is a residual — an observed value minus what it should be — fed into one engine. Only the GPS channels come from the satellite constellation; the rest are deliberately independent of it.
GPS-reported UTC minus the local clock
Time spoofing, receiver faults
Distance of the reported fix from the surveyed site
Position spoofing, multipath
Spread of per-satellite signal strength
Spoofing tell — a single transmitter collapses the spread toward zero
Network time minus the local clock
Independent time cross-check
Widest disagreement among several NTP servers
A minority of lying time servers
Ed25519-signed time minus the local clock
Time reference an attacker cannot forge without the key
WWVB 60 kHz radio time minus the local clock
Terrestrial time, no network needed
Observed offset minus the local clock's own drift model
Slow manipulation that tracks nothing real
A slow spoof. GPS drifts away from the band while the independent references hold flat. CUSUM catches the accumulation.
A crude spoof. The reported position jumps away from the surveyed antenna, and the step detector fires at once.
An outage. The channels go silent, and the shaded gaps are the absence itself — jamming looks exactly like this.
A healthy site is the fourth. See all four in the dashboard demo, where GPS is plotted against the consensus band the independent references span — a hairline when everything agrees, fanning open when it stops.
Alpha. The monitor runs: the daemon, the detection layers, the storage and the dashboard are built and tested, and the independent time channels — NTP consensus, Roughtime, WWVB — are wired in and opt-in per site.
What is honestly not done: the solar channel exists as a predictor but is not yet wired into the daemon, and the star-tracker channel is a roadmap idea. The default thresholds are consumer-grade starting points, meant to be overridden, and have not been validated against real jamming or spoofing hardware. Treat them as a place to begin tuning, not as a calibrated defence.
There is no language model anywhere in it — nothing is generated, nothing is inferred. It is arithmetic on residuals, and the reason it can be trusted is that you can read every step of it.