Thanks @K4KDR we are going to check them in the next hours!
And a quick summary of the latest updates:
PHASMA-DIRAC:
Yesterday, 24hours after deployment we managed to decode the first beacons, after fixing some issues with the gain of our ground station at hsgr. We also send a command to increase the transmission gain of the satellite (Space to Earth).
Some hours ago we received some EPS telemetry that confirms panels deployment. Given the good battery status (fully charged) In the next pass we are going to try increasing the RX duration of the satellite in order to have more opportunities to communicate with it and also increase a little the battery temperature.
PHASMA-LAMARR:
Unfortunately no reception until now, we have sent some commands for rebooting but no success until now. We are waiting for the internal watchdog (48h) to reset later today the satellite (if no commands has been received until now).
From now on we are going to send only reboot commands, just in case it is received from the satellite. So, either reboot command is received or watchdog resets the satellite.
In mission’s ground stations we also get CRC fails but we also managed to get several good frames.
There was a discussion about it in the PHASMA matrix chat channel https://matrix.to/#/#phasma:matrix.org. @PE0SAT@sdoukos and @DL4PD@surligas maybe you can help answering the question above.
Given that we don’t have any signals from LAMARR until now and post-launch TLE sets start getting off, we decided to generate TLE for LAMARR based on DIRAC’s TLE. I’ll give more details on this decision later in the daily update, for now here is the TLE:
Thank you very much for the CRC settings! Mine match, so it’s very probably just an SNR issue on my end.
I was not attempting any Doppler correction in these early days after deployment since I was in ‘search’ mode to locate & characterize the signals. All of my decodes are on replay after the Doppler offset of each bursts of packets was determined.
Going forward, I have added a Source Block to GNU Radio for my Airspy-R2 SDR with doppler correction and will start decoding & uploading to SatNogs “live”.
As for the CRC errors, of course the higher the baud rate, the more SNR is required for 100% clean decodes. It seems highly likely that that’s all I’m dealing with here on PHASMA-DIRAC.
After removing the CRC Check block and the adding it again I got different behavior and decoded frames. I will share the full IQ and latest flow-graph at the following location.
PHASMA-DIRAC:
The satellite continues to be in good status. We got several telemetry frames in the last passes, we see an increase in the battery temperatures as expected after the increase in its RX duration.
The next steps, given the good pass we have later today, we are going to get more telemetry and try to activate/enable ADCS subsystem and get some sensor values. The latest produced TLE looks good.
There were some frames sent to the dashboards without crc check(?) giving some non-normal values, for example for temperatures or for the GNSS status etc. So, we are going to remove them from the dashboards for now to have a better picture of the satellite status. However the frames will continue to be in SatNOGS DB in case we need them for further analysis.
From SatNOGS Network observations, as well as from the observations on PHASMA stations, we noticed that there is a slow tumbling, with rough estimation it rotates from every 30 seconds to every 1-2 minutes.
PHASMA-LAMARR:
No updates, still nothing heard. In case that it didn’t received anything from ground station, it supposed to be reset by the watchdog ~12 hours ago, but there is a chance that it received some commands but we just didn’t see it respond. Given the above we are going to wait ~48h from the last command we sent (about 24 hours from now).
Without signals we didn’t produce any more accurate TLE, so until now we’ve used the post-launch TLE set from satcat.com. However we noticed that post launch TLE sets from other missions, as well as from PHASMA-DIRAC, has started to be deprecated, so we decided to start using PHASMA-DIRAC’s ones for PHASMA-LAMARR.
This decision was based on the fact that they have the same mass and they were deployed with a small time difference. Another factor that could affect the orbit and the difference between the two, is if both of them have deployed their panels, however at the current altitude the B* drag is very low so it shouldn’t affect a lot the orbit even if the one has panels deployed and the other not.
Ground Segment:
We continue to improve the ground stations setups. We noticed that on UHF commands from hsgr station are not acknowledged from PHASMA-DIRAC, so we are looking on this matter and will do some experiments in the next pass. We will experiment with the gain of transmission, in case that saturates our signals and also we will increase the transmission window in case that it is to short for PA to be ready.
On the S-band side, we want to re-check the setups and make sure that working properly in order to close the two-way communication with PHASMA-DIRAC and try to communicate in S-band with LAMARR if we don’t have any update.
On SatNOGS side, we have many reception but unfortunately no decoded frames. There are variable reasons for this, the one is that many stations haven’t been updated yet to the latest version that is able to decode frames from PHASMA satellites. Another issue could be the SNR of the stations given that most of them have antennas calibrated for the UHF radio amateur band (435-438MHz), so they don’t perform that well at 400-403 MHz. Other factor that may affect the SNR are the transmission type (modulation, bandwidth), the power and the noticed tumbling of the satellite.
Thanks for all the info, Jan! As for the FSK Demod, CCSDS Deframer, & CRC Check blocks, everything is identical here. So, I’m comfortable that it’s just a signal quality issue on my end. Pre-launch, I got clean decodes from the sample file that was provided, so I’ll hope for a bit more SNR down the road.
Replacing the CRC Check block was my solution, I guess coping blocks out of other flow-graphs isn’t such a good idea.
I wonder if adding a FIR filter would also help in getting better results but I haven’t been successful in creating these blocks, some lack of knowledge and experience,
Using the SDR Source within GNU Radio (w/ doppler correction) worked fine on the DIRAC pass tonight… 15db and greater SNR. Was hoping for ‘live’ decodes for upload to SatNogs, but unfortunately, while numerous frames were decoded, not a single one passed the CRC-check.
Phasma-Dirac decodes. 12 frames in real time with CRC check. RX in EM12jw. After several failed attempts, chose to increase input bandwidth of demodulator to 300k sps. Tks project team, PE0SAT and K4KDR for flowgraph hints!
