Observation 14744248

329CZ144IPERDRONE.0NORAD 60520FSKlabel: without-signalqueue rank 10

the fitted corridor, the path the matched filter scored, with its half width shaded. the same pass geometry at zero frequency offset. the commanded receive frequency, where a Doppler-corrected capture would sit. The gap between the first two is the measurement. Scale: 95.9 Hz per pixel across, 0.191 seconds per pixel down, drawn one screen pixel to one measured pixel.

The black and white points open at a fixed pair, not one fitted to this image. Across the 25 committed waterfalls the noise floor runs from 0.20 to 0.38, so on most observations the ramp starts well below the first real sample and a weak pass reads flat until the black point is raised toward the floor.

Reviewer note

generated, checked

The observed transmitter mode is FSK, which contradicts the network label indicating no signal. Focus on the frequency range around 401 MHz. A definitive observation would be a clear, distinct signal within this range, settling the question of signal presence.

Written by granite3.1-dense:8b (8.2B, Q4_K_M) from this observation's evidence packet, and accepted by the grounding checker: every number in it appears in that packet.

Check a claim about this observation

The grounding checker from the pipeline, ported to TypeScript and running here. Edit the sentence, or start from one of the drafts below, and the verdict changes as you type. Nothing is sent anywhere: the whole rule set is in the page.

260 of 700 characters

GROUNDED

Every number in this sentence is a token of the packet below, every code and label in it is this observation’s, and no permission rule fired. That is all the checker claims: the sentence is consistent with what was measured, not that the measurement is right.

The evidence packet this is checked against, exactly as the model was shown it
observation_id             : 14744248
ground_station_id          : 5068
ground_station_name        : 329CZ144
norad_catalogue_id         : 60520
transmitter_mode           : FSK
receiver_frequency_hz      : 401110000
network_label              : without-signal
pass_duration_s            : 296
max_elevation_deg          : 28.5
closest_approach_fraction  : 0.50
fitted_offset_hz           : -10164
fitted_offset_ppm          : -25.3
corridor_half_width_hz     : 2000
sigma_curved               : 0.5
sigma_vertical             : 0.3
hz_per_pixel               : 95.9
seconds_per_pixel          : 0.19
axis_derivation            : axis_ticks_ocr
axis_derivation_confidence : 0.94
model_probability          : 0.500
ensemble_uncertainty       : 0.0199
flat_row_fraction          : 0.00
queue_rank                 : 10
queue_score                : 0.582
queue_reason_codes         : STALE_CATALOGUE_FREQ
offset_at_bound            : false

The closed world. A number that is not a token of this text is not grounded, which is why 6490 is refused although those digits appear inside 436490000: containment is not membership, and a transposed offset passed the old check for exactly that reason.

The pass

The same propagation that produced the corridor above, drawn from the station's point of view and from orbit. Elevation is measured from the WGS-84 geodetic normal, which is the reference the corridor was scored against.

Sky track

Azimuth clockwise from true north, elevation from the horizon at the rim to the zenith at the centre. The open circle is the rise, the square is the set, and the filled mark is closest approach at 28.5°.

NESW3060

Ground track

The subsatellite point, the station as a cross, and the satellite’s horizon circle at closest approach from 349 km. There is no basemap: this console ships no coastline data and will not draw one it cannot cite.

30405060-20-10010203040

Elevation and Doppler against time

The same pass on a time axis. Two stacked panels rather than one panel with two vertical scales, because a twin-axis chart lets the author choose where two curves appear to cross. This window spans closest approach, and the Doppler zero crossing lands on the sample where elevation peaks, because both happen at the same instant.

0306090ELEVATION, DEG+10k0−10kDOPPLER, HZ074148222296SECONDS FROM THE START OF THE RECORDING
Every row is a field of the exported geometry, not a figure read off the plots.
QuantityValueWhere it comes from
Maximum elevation28.483°Highest sample of the propagated pass, from the geodetic normal
Azimuth at closest approach262.55°Clockwise from true north
Slant range at closest approach677.1 kmStation to satellite, the minimum over the pass
Closest approach, as a fraction of the pass0.50100 is the start of the recording window, 1 the end
Samples propagated512An error count above zero means the orbit model refused part of the window, and the track is drawn only where it did not

The fit

Frequency offset
-10164 Hz
-25.3 ppm of the catalogue downlink
Corridor half width
2000 Hz
20.9 pixels at this image scale
Max elevation
28.5°
pass geometry from the TLE that was current at capture
Closest approach
50%
through the observation window, where the Doppler curve is steepest
Detection strength against corridor offset-4.5-2.00.5-20.0-10.0010.020.0corridor offset, kHzsigma0.50σ at -10,164 Hz
Matched-filter sigma at every whole-pixel offset the fit was allowed, subsampled for transport with the peak and both endpoints always kept. The peak is the fitted offset: the same function produces both, so they cannot disagree. The curve is what makes the fit a measurement rather than a choice, because a corridor that were merely near the trace would give a flat sweep with no peak to find. Scored at 419 offsets, 141 plotted.

The fitted curve is the predicted Doppler curve shifted by the fitted frequency offset, which is the path the matched filter scored.

The predicted curve is the same shape at zero offset, so the gap between them is the measurement.

Time runs bottom to top: the first row is the end of the pass.

The frequency axis runs against the Doppler sign.

Why it is in the queue

The composite score and the criteria it met, from the queue receipt.

FieldValueWhat it is
Rank10inside the review budget of 50
Composite score0.581585rank-normalised blend of model disagreement, uncertainty and physics
Model p(signal)0.500000calibrated probability from the shipped image and corridor arm
Ensemble spread0.019907disagreement between seeds; a proxy for how sure the arm is
Flat rows0.0000fraction of the waterfall with no luminance variation
Episode5068:60520:11station, satellite and orbital revolution: the unit the interval is grouped on
ConflicttrueStale catalogue frequency

Precedent

The five nearest passes in the snapshot under the Granite embedding of a text card built from this pass's numbers.

Two conditions: any station, and then a condition that excludes this station and this satellite so a neighbour cannot be a near-duplicate of the query.

The measured agreement is on the precedent page, and under the second condition it does not beat chance.

ConditionNeighbourStationSatellite (NORAD)StartNetwork label
Any station147442275068590682026-08-09T19:23:15Zwith-signal
147382865068571662026-08-09T20:32:14Zwithout-signal
147442375068984952026-08-09T20:42:16Zwithout-signal
147382855068571662026-08-09T18:50:38Zwithout-signal
147442205068617412026-08-09T17:50:21Zwith-signal
Other station, other satellite147319435055580212026-08-09T21:52:32Zwith-signal
147319365055580222026-08-09T21:33:12Zwith-signal
147319605055359352026-08-09T21:41:50Zwith-signal
147382615055400692026-08-09T15:34:51Zwithout-signal
147310915055983952026-08-09T21:14:48Zwith-signal
This pass carries the network label without-signal, station 5068, satellite IPERDRONE.0 (NORAD 60520). Counting how many neighbours match that label is one draw and settles nothing on its own. The neighbours link to the network rather than to this console, because most of them are outside the shipped set and the console carries no imagery for them.

Provenance

Enough to fetch the original and check it.

FieldValue
Sourcenetwork.satnogs.org/observations/14744248
Original waterfall SHA-256bbcc142dd44909edc1f30d7aba41d142e9c44c552d3e732e92712653a9eff450
Window2026-08-09T22:40:26Z to 2026-08-09T22:45:22Z
Receive frequency401,110,000 Hz
Axis derivationread off the spectrogram's own tick labels (confidence 0.94)
Displayed imageunweighted mean of the R, G and B channels, 8-bit