Observation record.Satnogs-VHF.2021-04-19T20-06-00

Ground-station Satnogs-VHF
Owner N5CNB

Waterfall
DopplerComparaison
PostProcessing

Résumé de l'événement

satellite LUSAT_(LO-19)
date 2021-04-19
time 20:06:00
duration 590
freq 4.37125e+08
culm 52.55

Waterfall

The graph at the bottom left gives the waterfall (time on the abscissa, frequency on the ordinate). The graph at the top gives the integrated signal strength in frequency as a function of time. At the bottom right, the average of the spectra over all the measurement times (frequency on the ordinate).

The time range of the measurement is given in the top right part (minimum_time, maximum_time). The frequency range determined by the number of points used by the Fourier transform is given by fmin and fmax. The units used for power (or the energy received in each time slot) could not be determined.

transitfile record.Satnogs-VHF.2021-04-19T20-06-00.transit

Additional capture data

The beginning of the transit is marked by a circle and the end of the transit by a disc.

• paramètres prévus
  filename record.Satnogs-VHF.2021-04-19T20-06-00
  satellite LUSAT_(LO-19)
  date 2021-04-19
  time 20:06:00
  samp 250000
  duration 590
  freq 4.37125e+08
  culm 52.55
• paramètres réalisés
  recfile record.Satnogs-VHF.2021-04-19T20-06-00.dat
  start 2021-04-19T20:06:00
  end 2021-04-19T20:15:52
  freq 4.37125e+08
  gain 50
  ns 590
  samp 250000
  nsamp 147500000

Gaussian fit

When the intensity of the signal as a function of time follows an approximately Gaussian law, this tool must capture approximately the parameters by non-linear adjustment. The adjustment is carried out using the NLOPT2 library. The behavior is undefined if the law is arbitrary.

abscisses: giga-samples name ordinates: sum_20000(I²+Q²)/1e6

• Resultats du fit
  t0 500000 [ 2 s]
  a 1000
  sigma 1500000
  y0 2000

calpower-stats

• Autres statistiques (de la valeur I²+Q²)
  moyenne 2.35082
  max 2.73174
  moyenne.debut.fin 2.37584
  hauteur.signal 0.3559 [ -4.48672 dB ] (max - moyenne.debut.fin)
  longueur.totale 590
  integrale.signal -14.7665 (somme - moyenne.debut.fin*longueur.totale)

Calculated and measured Doppler comparison

Abscissa: frequency in Hz
Ordinates: time in seconds

sumY2 3.63402e+09
sumDy2 3.43961e+08
dfmin 552.551 sumDy2 1.76933e+06
dtmin 0.00141986 sumDy2 1.76931e+06

* Kepler element data for LUSAT_(LO-19)

name ‘LUSAT_(LO-19)’
satellite_number 20442
central_object EARTH
ephemeris_type UnknownEphemerisType
epoch_year 21
epoch_day 108.43838988

• Kepler elements
  epoch_julday 2459322.93838988
  Time jd 2459322.93839 < 2021-04-18 10:31:16.0885 UTC >
  inclination 98.7356 deg [98 44'08"]
  right_ascension_of_ascending_node 63.3777 deg [4:13:31]
  major_radius 7160.73 km
  eccentricity 0.0011439
  periast_argument 343.212 deg [343 12'41"]
  mean_anomaly 16.8689 deg [16 52'08"]

• Supplemental data
  cc 1.99771481402
  ra 7.16892e+06 [797910]
  rp 7.15254e+06 [781528]
  va 7470.69
  vp 7453.62
  axb 7168.92 x 7168.91
  mammmdt 51.6333
  bstar 0.6496
  mean_motion_1st_deriv 2.7e-07
  mean_motion_2nd_deriv 0
  mean_motion 14.3298 rev/day 0.0697845 day/rev
  periapsis_distance 7152.54 km
  apoapsis_distance 7168.92 km
  periapsis_mean_height 781.528 km
  apoapsis_mean_height 797.91 km
  rev_number_at_epoch 63223
  tle_age 0.892154 day

* TLE

LUSAT (LO-19)
1 20442U 90005G 21108.43838988 .00000027 00000-0 26496-4 0 9999
2 20442 98.7356 63.3777 0011439 343.2115 16.8689 14.32982760632238

Spectrum analysis

median 1.86928
noise_level_db 1.93681
min -6.64623
max 29.3382
freq_center -1593.52
trig_level_db 10
nbin_rescaling 29.9957
freq_center_trig -1086.36
signal_range_dB 27.4014
theo_range_dB 48.1648 [ 8 bits ]

Post-processing

number of decodings: 0

Credits

Decodage gr-satellites v3.6.0 (Daniel Estevez)

N5FXH’s page

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