Vega VV16 launch (2020-09-03)

Satellites & Observations Launches
21

The current TLE are very good for receiving the newly deployed satellites.

Until now we have received AmicalSat and TRISAT.

TTU100 and UPMSat-2 haven’t been heard… but we still trying as many of the passes were low ones.

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22

TTU100 transmitter parameters in DB are correct

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23

Hi all, how can I put this custom TLE into Gpredict? Unfortunately Celestrak’s version it’s not updated with the new launch.

24

STRF observations by @pierros and myself find the following transmitters belonging to the VV16 launch.

  • 435.615MHz: as yet unidentified
  • 436.100MHz: AmicalSAT
  • 437.405MHz: UPMSat-2
  • 437.515MHz: as yet unidentified

I’ll update this post as more information becomes available.

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25

Until now we have received:

AmicalSat, UPMSat and TRISAT

Unfortunately nothing from TTU100.

We have added one more unknown satellite in DB that transmits in Radio Amateur band without coordination at 437.515.

Also we have some initial TLE sets from spacetrack, so we have started to use them for getting better results.

All five satellites have been scheduled.

26

Dear Fredy

Thanks to provide the very first data from UPMSat-2 satellite, launched recently.
A minor correction about receiving mode: it is FSK, not AFSK as stated in the DB. That means you need to switch to USB (or LSB) mode to receive data at 1200bps.
Your TLE seems good. We have the preliminary from Arianespace:
1 99999U 20999C 20247.10526620 .00000038 00000-0 12762-4 0 18
2 99999 97.4580 310.2540 0014300 070.7990 076.3347 15.15988174 992

(99999U is a fiction until NORAD give us the right ID)

That is all.
Rafael, EA4BPN, member of UPMSat-2 team.

UPMSAT-2 public telemetry codification https://www.amsat-ea.org/app/download/11965940/UPMSAT2+-+Public_TM_v1_2.pdf

UPMSAT-2 public telemetry decoding software https://www.amsat-ea.org/app/download/11965964/upmsat2_v1_2.exe

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27

Thanks, fixed on DB and on the future observations

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28

What is bandwidth of USB modulation to recieve 1200bps FSK speed?

29

It should be standard phone, around 2.8 kHz. You need to match 1.2-2.2kHz tones of ax.25 in your packet decoder.

Sound sample https://drive.upm.es/index.php/s/bJI7a643o5u47CZ/download

30

Until now we have:

  • UPMSat-2: received, currently described well by 46275, 46276(selected in network), 46277, 46278

  • TRISAT: received, currently described well by preliminary TLE of Vega VV16 launch (2020-09-03)

  • TTU100: not received, we try to track it with 46275. https://network.satnogs.org/observations/2784504/ seems to have something but we don’t see it on other observations that were performed at the same time.

  • AmicalSat: received, currently described well by preliminary TLE of Vega VV16 launch (2020-09-03)

  • Unknown satellite: received, currently described well by 46272, 46273, 46274(selected in network)

31

There currently is no USB demodulator in SatNOGS.
With the combination of not-quite-precise-enough doppler correction in these early days and stations individual ppm offsets, keeping a narrow FSK signal within a SSB demodulator is difficult.

Instead, you’re going to have to make use of the fm-demodulated output of the FSK demodulator, which is what is currently set up. It should be possible to bit-slice this output.

It looks like you are transmitting without scrambling? (I think the FSK demod expects this).
Maybe @surligas can indicate if the current FSK demod flowgraph can be used to receive this telemetry.

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32

Bandwidth : 900 Hz for the 300 bauds mode and 3400 Hz for the 1200 bauds one.
On USB mode filters cut off audio above 1.2KHz.

Here is UPMSat-2 usb audio signal imported in UZ7HO soundmodem.
USBmod

Sound sample audio is 5KHz wide so it is easy decode:

1:Fm UPMST2 To EA4BPN Via UNDEF [01:41:55R] [+±]
c 7Ïÿÿÿÿðy×0-„@È)q*àÀMðOàNgöëg§jö}0us0s0x†ÍmÕàMàILP`€KqWr’q×?ÿ

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33

Hello!

I am also a team member of TTU100. I was wondering whether it makes sense to use the TLE of 46275 as the target for the CubeSats launched later (from 3 Sept 03:33:32). Of course, I am assuming that 46275 is one of the bigger satellites launched in the beginning.
A simple two-body analysis shows that with 24 hours, the difference might already grow to 2000 km on the ground track. In one of my example cases the antenna pointing was as follows:
Azimuth 288.7°, elevation 50.7° (515 km orbit)
Azimuth 182.4°, elevation 7.5° (530 km orbit)

I had done an estimation for the TLE pre-launch with STK’s HPOP (High-Precision Orbit Propagator). I used the pre-launch TTU100 vectors and propagated the satellite for 24 h. The result I used as a basis for TLE calculation. Unfortunately the full licence I used at my university expired and as such cannot do further propagation investigations right now.

A picture from STK from today afternoon is show below.

TLE_Difference
TLE_Difference1553×712 556 KB

If needed I could share my calculated TLE or any further pictures from STK.

34

Please do, we used these as they were the first ones for this launch from spacetrack but it seems for many of the satellites is not very accurate.

PS Have you received any signal yet?

35

Ok, this is the TLE:

1 NNNNNU 20061    20247.15007234  .00012616  00000-0  75938-3 0 0000N
2 NNNNN 097.5174 320.2827 0001428 234.5934 156.7344 15.1089865200003N

It was calculated from the following vector:
TTÜ100
Tsep/H0 (s): 6296,25
X/Y/Z J2000 (m): 4233659,31086458 / -4155902,16355396 / 3544922,5095557
Vx/Vy/Vz J2000 (m/s): -3557,16954402693 / 1886,01524760547 / 6440,59040933349

HPOP parameters:
Mass 1300 g, area 0.02 m^2, Cd 2.2. Otherwise default STK values.

As far as I know we have not received any signal yet.

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36

I’ve updated TTU100 with the new TLE and re-scheduled the future observations as they were too off with the new TLE.

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37

A quick update:

  • UPMSat-2: received, currently described well by 46275, 46276(selected in network), 46277

  • TRISAT: received, currently described well by preliminary TLE of Vega VV16 launch (2020-09-03)

  • TTU100: not received, currently trying to track it with preliminary TLE of Vega VV16 launch (2020-09-03)

  • AmicalSat: received, currently described well by preliminary TLE of Vega VV16 launch (2020-09-03)

  • Unknown satellite: received, currently described well by 46272, 46273(selected in network), 46274

38

I was wondering whether the SatNOGS database has been set up/updated properly for TTU100. The database uses FSK 9600 at 435.450 MHz but it has not specified “standard G3RUH encoded AX25 packets”. Also, the “morse transmission on a same frequency using unmodulated carrier” is missing. Do I understand correctly that it would correlate to CW?

39

We can not currently add information like that, however in clients AX25 is what the default demodulator tries to demodulate for FSK.

Please login in https://db.satnogs.org and suggest this transmitter (you can do it by hitting edit button at the top right corner on the satellite page).

3 Likes
40

A quick update, used TLE sets don’t fit accurately the signals (except UPMSat-2), however are still good for tracking the satellites.

Another update is that the last observations of TRISAT hasn’t any signal.