BurkinaSat-1 project is an initiative of Universtity Nobert Zongo project in Burkina Faso West African Country. The satellite is transmitting becon data via UHF band at 437.X Mhz frequency
amateur radio can get the burkina-sat1 Becon Telemetry by using process below.
- Use SDR radio at frequency UHF 437.X Mhz (Note the X value will be provide by IARU after validation)
- Use GQRX and a compatible SDR
In the GQRX main GUI, several things must be configured:
In the Input Controls tab: Ensure the DC Remove checkbox is checked. Adjust RF, IF and BB gains according to your needs. Common values that usually work on RTL-SDR, depending on the noise around the antenna and the strength of the satellite signal are shown below. However, playing around with these values to find the optimal combination of gains is recommended.
- RF: 0 dB, IF: 16 dB, BB: 20 to 32 dB
- RF: 0 dB, IF: 24 dB, BB: 20 to 24 dB
- RF: 14 dB, IF: 16 dB, BB: 20 to 24 dB
- RF: 14 dB, IF: 8 dB, BB: 20 to 32 dB In the Receiver Options tab: The satellite sends GMSK-modulated data. To demodulate such satellite signals, select Narrow FM as the demodulation mode. The filter width can be left to Normal, as this usually gives enough bandwidth for the 4800 bps frames from Quetzal-1. In the FFT Settings tab: Set the FFT size to 32768. This usually makes the spectrum cleaner. You can adjust the zoom on the FFT display to fit your needs. Make sure port 7355 is configured for UDP. To do so, click on the ... button next to Rec and select the Network tab. Then configure: UDP Host: localhost UDP Port: 7355
Burkina-Sat1 is deployed using Gomspace hadware and software at some point . Burkina-Sat1 use UHF @435.200 Mhz for down link and up link transmission. For downlink, Burkina-sat1 uses a GOMSpace AX100 transceiver, which transmits GMSK-modulated data at 4800 bps at 437.X.200 MHz. Beacons are encapsulated in AX.25 + HDLC frames, with G3RUH scrambling and NRZI encoding. The following image shows the overall beacon format:
Once you downloaded and installed the Gqrx Software defined radio, you can use RTL-SDR dongle to attach your your ground station UHF antenna or use the anntena provided by RTL-SDR. Attach your Gqrx to your RTL-SDR by selecting USB as connexion port
Please clone the gr-satellites project providing a decoder to decode the data that received from Gqrx .
gr-satellites is a GNU Radio out-of-tree module encompassing a collection of telemetry decoders that supports many different Amateur satellites. This open-source project started in 2015 with the goal of providing telemetry decoders for all the satellites that transmit on the Amateur radio bands.
It supports most popular protocols, such as AX.25, the GOMspace NanoCom U482C and AX100 modems, an important part of the CCSDS stack, the AO-40 protocol used in the FUNcube satellites, and several ad-hoc protocols used in other satellites.
Once you cloned the gr-satellites project and followed the instruction for installation, you an run the decoder using the command line as follow: $ gr_satellites usage: gr_satellites satellite [-h] [--version] [--list_satellites] [--ignore_unknown_args] (--wavfile WAVFILE | --rawfile RAWFILE | --rawint16 RAWINT16 | --audio [DEVICE] | --udp | --kiss_in KISS_IN) [--samp_rate SAMP_RATE] [--udp_ip UDP_IP] [--udp_port UDP_PORT] [--iq] [--udp_raw] [--input_gain INPUT_GAIN] [--start_time START_TIME] [--throttle] [--kiss_out KISS_OUT] [--kiss_append] [--kiss_server [PORT]] [--kiss_server_address KISS_SERVER_ADDRESS] [--zmq_pub [ADDRESS]] [--hexdump] [--dump_path DUMP_PATH]
Next step you should provide the recording wav file you got from the SDR recording the becon Telemetry : below you have the all process :
