VIOLET's radio-info

Violet

VIOLET's permanent web address (unb.ca/cubesat-radio-info) is redirected to this page which the public and SatNOGS will use to access technical information regarding the radio interface and description of the protocols.

That permanent web address was documented with the Radio Amateurs of Canada (RAC); that address was also be sent to Innovation Science and Economic Development Canada (ISED) / Government of Canada, the International Amateur Radio Union (IARU) and the International Telecommunication Union (ITU).

Radio licence type

VIOLET is planned to transmit only when it is near the ground station at the University of New Brunswick, Fredericton, in response to an authenticated and encrypted uplink command. Scientific data is planned to be downloaded. VIOLET's radio licence is developmental/amateur radio; VIOLET is not an amateur radio sateliite.

Project description

CubeSat VIOLET is approximately 10 cm by 10 cm by 20 cm. VIOLET was designed, built, and tested, by the students in our group called CubeSat NB, a first-of-its-kind partnership among the New Brunswick Community College, the Université de Moncton and the University of New Brunswick. The purpose of the project is student education and nearly 300 students have been part of this project. CubeSat NB is one the 15 teams in the Canadian CubeSat Project, inspired by the Canadian Space Agency. VIOLET is named after the purple violet, the floral emblem of the province of New Brunswick. VIOLET's mission is to study space weather, using passive magnetic attitude control, with hysteresis rods, in low Earth orbit, near the peak of the eleven-year solar cycle, using the voltage and current from its four photovoltaic panels, and two internal temperature sensors.

Frequency coordination

Downlink physical-layer parameters

The technical downlink parameters are:

  • carrier frequency of 436.830 MHz,
  • 25.36 dBm EIRP,
  • effectively a 2.1 dB dipole antenna gain in VIOLET, but VIOLET has passive magnetic attitude control and over its ground station, would have similar attitudes and would rotate around the magnetic field,
  • BPSK modulation at 9600 bits/second,
  • 0.5 roll-off-factor with raised-cosine pulse shaping,
  • emission designator 15K0G1DAN,
  • 15 kHz bandwidth,
  • G3RUH scrambling polynomial x17+x12+1,
  • NRZ-I encoding, and
  • AX.25 downlink packets, described next.

Downlink AX.25 packet format

  • In response to one encrypted-and-authenticated uplink packet, VIOLET will transmit 25 AX.25 downlink packets.
  • Each downlink AX.25 packet has:
    •  connectionless and UI frames,
    • a source call sign VE9VLT-1,
    • a destination call sign VE9CNB-1, and
    • 243 bytes from a
      • 16 byte header, and
      • 227 bytes of data.

Downlink data format

The 227 bytes of downlink data contain data from the electrical power supply and the RF transceiver.

  • Counter buffer index, 2 bytes
  • Counter next id, 4 bytes
  • Counter next iv, 4 bytes
  • Electrical power supply, 177 bytes
    • Power integrated unit (PIU) status, 1 byte
    • PIU software version number, 1 byte
    • PIU response code, 1 byte
    • PIU board identifier, 1 byte
    • PIU reserved, 1 byte
    • Voltage on board supply, 2 bytes
    • and so on.
  • RF transceiver, 40 bytes
    • Uptime, in s, 4 bytes
    • Transmitter instantaneous RF reflected power, in ADC units, where it could be converted later to dBm using 20 log10(0.00767 * ADC), 2 bytes
    • and so on.

VIOLET's launch and deployment

  • The launch of VIOLET from the Kennedy Space Center to the International Space Station (ISS) is planned for March, 2024, but can change due to a variety of reasons, such as weather.
  • The deployment of VIOLET from the ISS is on a date not known at this time, likely between March and May, 2024.
  • In the first week after deployment, VIOLET's orbit will be similar to the ISS,
    • apogee 408 km,
    • perigee 403 km,
    • orbit inclination 51.6 degrees and
    • orbital period of 92.7 minutes.
  • The orbit will decay quickly after three to six months near the peak of the eleven-year solar cycle.

CubeSat NB ground station, earth station

At this time, the planned CubeSat NB ground station

Amateur radio activities at the University of New Brunswick

Some activities are documented at

Uplink command and control

  • cubicrypt is used for encryption and authentication, where required for communication to VIOLET and control of VIOLET.