orbcomm-rx
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π‘ Demodulator and decoder for the Orbcomm VHF Subscriber Transmitter (STX) downlink.
π‘ orbcomm-rx - STX Demodulator and Decoder
orbcomm-rx is a demodulator and decoder for the Orbcomm VHF Subscriber Transmitter (STX) downlink. Each satellite in the Orbcomm constellation transmits two STX carriers between 137-138 MHz. These downlinks contain satellite position data, orbital elements, uplink/downlink channel info, and encrypted user messages.
Demodulator
The STX downlinks are modulated using Symmetrical Differential Phase Shift Keying (SDPSK) at a data rate of 4.8 kbps.

Decoder

Resources
- βEver wondered what is on the Orbcomm Satellite Downlink?β - Mike Kenny
- "The Orbcomm Experience" - Jochen Harms