INFORMATION FOR COMMUNICATING WITH FLORIPASAT-1

FloripaSat-1 communicates through VHF and UHF bands

Operation Parameters

COMMUNICATION: VHF

Beacon

The beacon is sent constantly and provide the satellite basic stats and data.

COMMUNICATION: UHF

Downlink and Uplink

Also constant, the downlink provide complete satellite packet. Uplink allows telecommands to be sent.

OPEN COMMANDS

Repeater

Open to the ham radio community, there are three open commands: ping, data request and message broadcast.

PROTOCOLS

NGHam e AX.25

FloripaSat-I uses two different protocols: NGHam and AX.25. Both for VHF and only NGHam for UHF.

DATA

Decoding

Using the FloripaSat-1 custom-made software, it is possible to process and decode the collected data.

Tracking

Use the following information for tracking:

NORAD ID: 44885

International Designator: 2019-093G

Orbit

Altitude: 628.6km;
Inclination: 97.9°;
Cycle Repetition: 31 days;
Orbit Period: 5835 seconds;
Ascending Node Local Time: 10:30 a.m.

Couldn't understand how to capture the FloripaSat-1 signal with the information on the page? Check out our step by step guide

We understand that the amount of information can make some people confused, so we made a guide for those interested in capturing the Beacon telemetry signal in a simpler way.

Click the button below to be directed to the step-by-step docs:

  • Frequency: 145.9 MHz
  • Protocol: NGHam and AX.25
  • Modulation: GFSK
  • Deviation: 2,5 kHz
  • Baudrate: 1200 bps
  • Output Power: 30 dBm (1 W)

The Beacon of FloripaSat-I transmits packets periodically, with 5 possible periods (accordingly to the overall energy level of the satellite):

Energy LevelBeacon Period [s]
L1 (100% – 90% of total battery charge)10
L2 (92.5% – 80% of total battery charge)10
L3 (82.5% – 70% of total battery charge)20
L4 (72.5% – 60% of total battery charge)30
L5 (62.5% – 0% of total battery charge)30

In normal satellite operation, the beacon packets contains the following data:

FieldOffsetLength [bytes]Content
Satellite ID010“FLORIPASAT”
Batteries voltages104Variable
Batteries tempearatures146Variable
Total charge of batteries202Variable
Solar panels currents2212Variable
Solar panels voltages346Variable
Overall status of the satellite402Variable
Accelerometer and gyroscope4212Variable
Time since boot544Variable
Number of OBDH module resets since launch582Variable

If a fault on the OBDH module occurs (if the TTC module stops receiving data from it), only the EPS data are transmitted:

FieldOffsetLength [bytes]Content
Satellite ID010“FLORIPASAT”
Batteries voltages104Variable
Batteries tempearatures146Variable
Total charge of batteries202Variable
Solar panels currents2212Variable
Solar panels voltages346Variable
Energy level401Variable

If a fault occurs in the OBDH and EPS modules, only the satellite ID is transmitted:

FieldOffsetLength [bytes]Content
Satellite ID010“FLORIPASAT”
  • Frequency: 436.1 MHz
  • Modulation:2- GFSK
  • Protocol: NGHam
  • Deviation: 5 kHz
  • Baudrate: 2400 bps
  • Output Power: 30 dBm (1 W)

The Downlink of FloripaSat also transmits packets periodically (it contains a lot more data than the beacon packets), accordingly to the energy level of the satellite:

Energy LevelDownlink Period [s]
L1 (100% – 90% of total battery charge)60
L2 (92.5% – 80% of total battery charge)60
L3 (82.5% – 70% of total battery charge)120
L4 (72.5% – 60% of total battery charge)120
L5 (62.5% – 0% of total battery charge)none

The content of each periodic downlink packet is described in the table below:

FieldOffsetLength [bytes]Content
Flags02Variable
OBDH Status26Variable
IMU Accelerometer812Variable
IMU Gyroscope2012Variable
OBDH Misc.326Variable
OBDH Uptime384Variable
Solar Panel Sensors4212Variable
Main Radio5419Variable
Solar Panels Data7318Variable
EPS Misc.918Variable
Battery Monitor9921Variable
Temperatures12021Variable
Energy Level1411Variable
RUSH Data14240Variable
Payload X1827Variable

The downlink also transmits sporadic packets with the answers of the uplink telecommands.

  • Frequency: 436.1 MHz
  • Modulation: 2-GFSK
  • Protocol: NGHam
  • Deviation: 5 kHz
  • Baudrate: 2400 bps

There are three types of uplink packets: Data request, ping and message broadcast. Each one is described in the table below:

CommandLength [bytes]Content
Data request8“dr” + flags
Ping8“pg” + requester callsign
Message broadcastUp to 28“br” + requester callsign + message
  • Data request: To request data of the satellite use this command. Selecting the flags, the user can download a set of past data of sensors or modules.
  • Ping: This command can be used to test the communication with satellite. When received, the satellite transmits back a ping packet.
  • Message broadcast: When received, the satellite transmits back the same content (an string with up to 20 characters) with the callsign of the source of command. This command can be used for communication between two or more ground stations.

The two callsigns are showed below:

  • 0PY0EFS
NameID Code [1 byte]Data [up to 220 bytes]Data Size [bytes]Total Size [bytes]Acess Level
OBDH Data0x00OBDH/EPS data5090Public
EPS Data0x01EPS data3190Public
TTC Data0x02“FLORIPASAT”1058Public
OBDH Data0x03OBDH/EPS data5070Public
EPS Data0x04EPS data3151Public
TTC Data0x05“FLORIPASAT”1030Public
Telemetry0x10Flags (16 bits) + OBDH/EPS data212266Public
Ping answer0x11Requester callsign (ASCII)758Public
Data request answer0x12Requester callsign (ASCII – 7 bytes) + Data (140 bytes)7 to 14758 to 202Public
Hibernation feedback0x13Requester callsign (7 bytes) + Hibernation duration in hours (16 bits, MSB first)958Public
Charge reset feedback0x14Requester callsign (7 bytes)758Public
Message broadcast0x15Resquester callsign (7 bytes) + Destination callsign (7 byes) + Message (up to 38 chars)14 to 5290Public
  • 00PP5UF or any callsign
    NameID Code [1 byte]Data [up to 220 bytes]Data Size [bytes]Total Size [bytes]Acess Level
    Ping request0x20None058Public
    Data request0x21Data flags (16 bits) + Count (1 byte) + Origin (1 byte) + Offset (4 bytes)858Public
    Broadcast message0x25Destination callsign (7 bytes) + Message (ASCII, up to 38 characters)7 to 3890Public

NGHam

The figure below describes the NGHam protocol fields of each packet.

The only customized parameters from the protocol changed in FloripaSat-I, are the preamble and the sync. word, which are applied for both frequency communications:

  • Preamble: 0xAA, 0xAA, 0xAA, 0xAA
  • Sync. Word: 0x5D, 0xE6, 0x2A, 0x7E

More information about the NGHam protocol can be found here.

AX.25

The beacon packets are also transmitted using the AX.25 protocol (the same packet with both protocols).

FieldLength [bytes]Content
Preamble40xAA, 0xAA, 0xAA, 0xAA
Sync. word40x5D, 0xE6, 0x2A, 0x7E
Flag10x7E
Destination Address7Ground Station Callsign and SSID
Source Address7Satellite Callsign and SSID
Control10x03
Protocol Identifier10xF0
Data60, 41 or 10“FLORIPASAT” + Data
Frame Check Sequence2Variable
Flag10x7E

NOTE: The callsign and SSID of both satellite and ground station, will be defined accordingly to the obtained licenses.

More information about the AX.25 protocol can be found here.

To decode the packets, there is a custom made sofware developed by the group. This software is capable of handling SDR devices, receive/transmit the signals and code/decode packets.

More information about this software can be found here. To obtain the program, go to this page and download the latest release.

Also, see our tutorials on youtube.

video tutorials

Some steps are documented through tutorial videos, intending to turn the process more simple and clear.

If you do not have access to the software or are unsuccessful in decoding send us the signal audio via email (contact@spacelab.ufsc.br) and we will try to decode it. 

Any questions we will be pleased to answer, send via email or make a new “issue” in our GitHub page.

Could you capture a signal from FloripaSat-1? Email us and get your QSL card

To receive your QSL card send an email to contact@spacelab.ufsc.br containing the following information:

  • Full name with identifier number
  • Date containing day, month, year and time UTC of signal reception
  • Grid locator
  • Frequency used
  • Signal audio received in the format. wav
  • Important: the audio must be recorded directly from the radio or SDR, if recorded by a speaker the decoding will not be possible

If you want to describe the equipment that was used to capture the signal we will be happy know!

Our card comes in 3 different versions with different photos on the back, if you prefer one of them let us know! Check them out below:

Front of QSL card

Back team version

Back launch version

Back INPE version

With the support of the amateur radio community and the SatNOGS network, FloripaSat-1 has been heard beyond Brazil's borders

So far more than 15 radio amateurs around the world have recorded the FloripaSat-1 signal. Through the global network of SatNOGS stations more than 450 observations have already been made, check them out clicking here.

Special thanks to: DK3WN; KC4MCQ; JA0CAW; PA0DLO; K4KDR; VK5QI; PY2SDR; PY4ZBZ; BX2ABT; PV8DX; E29AHU; YC2SAT; PU5FTL; PY2DNR; PY417SWL; JH4XSY/1 and PU4JOE.

Join them and contact FloripaSat-1!

The FloripaSat-1 mission has finished its development and integration phase, but our work is not over yet.

Follow the SpaceLab UFSC lab to see recent activities from future space missions and group-led projects.

Contact us if you wish to join!

@ 2020 SpaceLab UFSC – Space Technology Research Laboratory, Federal University of Santa Catarina