46 lines
2.2 KiB
Markdown
46 lines
2.2 KiB
Markdown
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# SatNOGS flowgraphs
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This directory contains all the available flowgraphs that can be executed from
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the `satnogs-client`.
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## Contribution guide
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Flowgraphs are placed inside the `apps/flowgraphs` directory.
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If a decoding flowgraph targets only specific satellite/mission, the
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flowgraph should be placed inside the `apps/flowgraphs/satellites` directory.
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Each flowgraph should have a representative name (eg `voyager_decoder`) and
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both the GNU Radio file (`.grc`) and the generated pythons script should be available.
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Python auto-generared flowgraph scripts should have the `satnogs_` prefix.
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This can be performed by setting properly the `ID` field of the `Options` block
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of the flowgraph.
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For example the `voyager_decoder.grc` should generate a python executable named
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`satnogs_voyager_decoder.py`
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**NOTE:**: Custom python GNU Radio scripts are not allowed.
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Each flowgraph should be able to be generated from the corresponding `.grc` file.
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All generated python scripts should be installed using the `CMake` build system.
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To do so, edit properly the `apps/CMakeLists.txt` or `apps/flowgraphs/satellites/CMakeLists.txt` file.
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In the `apps/flowgraphs` directory, the is an example flowgraph called `example_flowgraph.grc`
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that can be used as a base.
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### Execution arguements interface
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The `stanogs-client` and the `gr-satnogs` communicate through a set of
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predefined command line arguments.
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Depending the decoding flowgraph, additional arguments may exist or missing.
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However, there is a set of mandatory arguments.
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* `--antenna`: The name of the antenna to use
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* `--dev-args`: SDR device specific arguments
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* `--bb-gain`: Baseband gain
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* `--if-gain`: Intermediate frequency gain
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* `--rf-gain`: RF gain
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* `--ppm`: The PPM correction
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* `--rx-freq`: RX frequency
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* `--rx-sdr-device`: The RX SDR device identification name (e.g uhd, airspy, etc)
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* `--rigctl-port`: The `rigctld` port
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* `--doppler-correction-per-sec`: Number of Doppler corrections per second
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* `--lo-offset`: Offset from the desired center frequency. The flowgraph should
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tune the SDR with this offset from the center frequency and digitally compensate it.
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This eliminate the problem of the DC leakage, expressed in the majority of the
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SDR devices.
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