Hey everyone! @EA4HCD or @FossaSys here.
I am the lead developer of the FossaSat-1 pocketqube satellite launching into LEO this october aboard an Electron. We just got coordinated a frequency of 437.600 MHz by the IARU for the satellite so I though it was an appropriate time to start asking the community.
For those that don’t know the project, this 5cm sided cube will mainly test the use of the LoRa modulation in space. (https://Fossa.Systems explains the project pretty well). Its a mostly open source and crowdfunded project.
Our LoRa configuration as default is SF11, CR4 at 125KHz. We can however change some of these settings for experimental purposes. RTTY is simple 45 baud ASCII stuff, seems like there’s no decoder for SatNOGS though.
Now regarding its function, the satellite mainly functions in a loop as follow:
- LORA Telemetry Packet TX on amateur (Voltages, states, config, sensors etc)
- LORA RX on ISM band (experimental ping/pong style commands or messages to be repeated)
- LORA RX on amateur (same as ISM but higher power and control commands)
- LORA TX Repeated messages / ping pong
- Sleep depending on batt voltage (couple s)
Every couple loops the following occurs:
- RTTY Telemetry Packet TX on amateur band
- GFSK RX on amateur (commands)
The loop is a couple of s so the latency between repeated messages is not much. LoRa can be recieved on the ground using a copper wire and a 3€ module, it would be great if reception could also be carried out on satnogs though. There has been some work on a LoRa GNU decoder which seems to work with SF11 but I still have a lot of testing to do and not enough time. I am guessing the RTTY should be easy to integrate considering the amount of external decoders.
Thank you very much!