Uplink Downlink
Frequency 70-centimeter band 145.950MHz
Modulation DBPSK BPSK
Baudrate 12.5kBaud 12.5kBaud
Sync Word 0x49E0DCC7 0x49E0DCC7
FEC None CCSDS-LDPC 1/2, 1k Block size

How to track MOVE-II (Deutsche Version am Ende der Seite)

To communicate with the MOVE-II Satellite we use a UHF/VHF communication module. The downlink of this module can be received by any interested radio amateur.
In its regular operation mode, MOVE-II transmits its CW callsign (DP0MVE) every 40 seconds and a short beep every 10 seconds. Additionally, the satellite transmits a data beacon every minute. The data beacon has a bandwidth of approx. 18 kHz, its modulation is described in the table above. The data sent down by the satellite is packed into Nanolink frames.

Orbital Parameters

The objects launched during the SSO-A mission have not all been identified yet. The best fitting TLE for MOVE-II are the ones of object Y:

2018-099Y               
1 43780U 18099Y   18347.79208705  .00000308  00000-0  33550-4 0  9991
2 43780  97.7660  56.8433 0012730 231.2418 128.7665 14.94852771  1488

Orbital parameters have been retrieved from Celestrak.com.

What does a typical MOVE-II overpass look like?

You should recognize the CW beeps and beacons every 10s. Every 60s, a data beacon is sent. Sometimes, the data beacon interrupts the CW transmissions. The signal-to-noise ratio of the data beacon is a lot lower than that of the CW beeps so the data beacons may not be visible at low elevation.

To make sure that it is really us that you are hearing, compare your observations to overpasses posted on the SatNOGS.org network.

The CW beacon is DP0MVE and should look like this:   -..   .–.  —–  —  …-  .

Contribute

We would be glad if you could help us to receive MOVE-II. We will also send you MOVE-II QSL cards and a little thank you in this case.

You can help us in two ways:

Option 1: Record baseband data and send it to us

We would be glad if you could send us everything that your ground station received during an overpass of MOVE-II. We will then analyze your data with our decoding software and give you feedback if we could extract data and what information was transmitted during the overpass.

Requirements

  • an SSB receiver (for hearing the CW transmissions) or an SDR if you would also like to capture enough bandwidth for the data transmissions)
    • Minimum bandwidth for data decoding is 25 kHz
    • An additional 6 kHz for the Doppler shift is needed if you should not have Doppler shift correction implemented
  • Software to capture the baseband
    • Standard software like SDR Console or SDR sharp is fine (Record the baseband at a precision of 16 bit)
    • GNU Radio is even better (Stream the signal in a file sink block)

Upload the recorded file on our Radio Submission page and please also give us the sample rate of your recorded file, the used frequency of your receiver, time and date of the beginning of your record and your location. If the uploader does not work for you, please send a submission without a file and we will send you a link to an alternative upload service.

During the next days, you should hear back from us and what we got out of your submission.

Option 2: Decode MOVE-II data on your Linux computer

You need an SDR with sufficient bandwidth and a ground station setup that gives you sufficient SNR of the data signals. This will most likely require a high-gain VHF antenna and a rotator and a low noise floor in your area.

Use the provided software to decode the signal. It is a compact distribution of GNU Radio along with the decoder blocks for the LDPC code, descrambling the bitstream, and recognizing the Nanolink frames. Here you can download the software: https://move2radio.lrt.mw.tum.de/download

Install

The AppImage itself can simply be started like a executable. On most linux systems you will have to mark the file as executable after download:

  1. right click on file
  2. properties
  3. permission
  4. mark as executable

SDR stick driver

To run this software you will need a SDR-stick compatible with gr-osmosdr.
The stick needs to be installed in your operating system for SDR usage. This means a udev rule will have to be installed and the kernel driver deactivated.

Example for rtl_sdr devices

The following is an example, you will have to find the exact udev rules needed for your device using google.
First create a file /etc/udev/rules.d/50-rtlsdr.rules with the following content:

SUBSYSTEM=="usb", ATTRS{idVendor}=="0bda", ATTRS{idProduct}=="2838", GROUP="adm", MODE="0666", SYMLINK+="rtl_sdr"

Then reload the udev rules:

sudo udevadm control --reload
sudo udevadm trigger

As final step remove the kernel driver (Note, see next if this does not work on your system):

sudo rmmod dvb_usb_rtl28xxu

To make this permanent, add the module to the module blacklist. Create a file /etc/modprobe.d/sdr.conf with the following content:

blacklist dvb_usb_rtl28xxu
and reboot!

Now start move2radio and it should detect the sdr stick!

Usage

Just start move2radio.AppImage and wait until it launches. The terminal that opens will tell you if there are any errors.
When the program started, your session-id will be printed in the terminal. To later see which data you provided to the MOVE-II project, write this session-id down.
Use the frequency slider to receive the correct frequency of the satellite.
The session-id that appears in the terminal can be used to register your call-sign or name on https://move2radio.lrt.mw.tum.de/
Your name/callsign will then appear on the leaderboard with the amount of frames your contributed.

Build

This repository provides the build script used to build move2radio. It downloads all needed sources as compiles them as needed.

AppImage

You can build the whole software package with the following commands:

mkdir build && cd build
cmake ..
make appimage

Components

Each component of the software can be built by itself. For example to build only the gr-ccsds gnuradio blocks:

make build_gr_ccsds

Similarily, to only build the exact gnuradio version used in move2radio:

make build_gnuradio

 

MOVE-II selbst empfangen

Für die Kommunikation mit MOVE-II verwenden wir ein UHF/VHF Modul. Der Downlink dieses Moduls kann dabei von allen Amateurfunkern frei Empfangen werden.
MOVE-II sendet im regulären Betrieb alle 10 Sekunden ein kurzes Piepen und alle 30 Sekunden sein Morse-Rufzeichen DP0MVE. Jede Minute wird die Telemetrie des Satelliten dann wie oben beschrieben gesendet.
Der Resultierende Bytestrom beinhaltet dann die eigentlichen Nutzdaten in Form von Nanolink Frames. Zum dekodieren dieser Daten stellen wir ein fertiges Softwarepaket zur Verfügung.

Wir würden uns freuen wenn Sie uns beim Empfang von MOVE-II unterstützen. Gerne senden wir ihnen auch MOVE-II QSL Karten mit einem kleinen Dankeschön des Teams zu.
Sie können uns auf zwei wege unterstützen:
Indem Sie uns eine Baseband aufnahme schicken. Hierfür benötigen Sie
– einen SSB Empfänger (oder ein SDR)
– zum späteren Dekodieren der Telemetrie wäre eine mindeste Bandbreite von 25kHz wünschenswert
– nehmen Sie die Daten bitte als rohe wave Datei oder als gnuRadio file mit complexen samples auf (mithilfe der GnuRadio file sink)
Wenn Sie uns diese Dateien zukommen lassen, geben Sie bitte auch die verwendete sample rate, die genutzte Frequenz am Empfänger, den genauen Empfangszeitpunkt (zu beginn der Aufnahme) und ihren Ort an.
ODER
verwenden sie die zur Verfügung gestellte Software um das Signal direkt zu dekodieren. Hier können Sie die Software downloaden: https://move2radio.lrt.mw.tum.de/download

Für aktuelle TLEs und Beobachtungen schauen Sie bitte auf SatNOGS (https://db.satnogs.org/satellite/99910/) und CelesTrak (Link sobald MOVE-II in der Datenbank auftaucht).