79 lines
2.7 KiB
Markdown
79 lines
2.7 KiB
Markdown
# JSON protocol
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This protocol was created by adsb-tools. This specification is official.
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## Format
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[JSON streaming](https://en.wikipedia.org/wiki/JSON_Streaming) encoding, line delimited.
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Each line must contain a single outer JSON object; no other outer types are permitted.
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First frame must always be a header; frames can otherwise appear in any order, including
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additional headers.
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## Common fields
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* `type` (string): one of:
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* `header` (see [Header](#header))
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* `Mode-AC` (see [Packet](#packet))
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* `Mode-S short` (see [Packet](#packet))
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* `Mode-S long` (see [Packet](#packet))
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## Header
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* `type`:
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* String
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* `header`
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* `magic`:
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* String
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* `aDsB`
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* `server_version`:
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* String
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* Unique identifier for this server implementation
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* Recommended: `https://url/of/source#version`
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* `server_id`:
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* String
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* Unique identifier for this server instance
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* [UUID](https://en.wikipedia.org/wiki/Universally_unique_identifier) recommended
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* 36 character limit
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* `mlat_timestamp_mhz`:
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* Integer
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* MHz of the clock used in subsequent `mlat_timestamp` fields
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* `mlat_timestamp_max`:
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* Integer
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* Maximum value of subsequent `mlat_timestamp` fields, at which point values are expected to wrap
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* `rssi_max`:
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* Integer
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* Maximum value of subsequent `rssi` fields
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## Packet
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* `type`:
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* String
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* One of:
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* `Mode-AC` (4 byte payload, 2 bytes when decoded)
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* `Mode-S short` (14 byte payload, 7 bytes when decoded)
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* `Mode-S long` (28 byte payload, 14 bytes when decoded)
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* `source_id`:
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* String
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* Unique value for the source that recorded this packet.
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* [UUID](https://en.wikipedia.org/wiki/Universally_unique_identifier) recommended
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* 36 character limit
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* `mlat_timestamp`:
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* Integer
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* Value of the [MLAT](https://en.wikipedia.org/wiki/Multilateration) counter when this packet arrived at the recorder
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* Range [0, `mlat_timestamp_max`]
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* Units of 1 / (`mlat_timestamp_mhz` * 10^6) Hz
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* `rssi`:
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* Integer
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* [RSSI](https://en.wikipedia.org/wiki/Received_signal_strength_indication) of the received packet at the recorder
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* Range [0, `rssi_max`]
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* Units unspecified
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* `payload`:
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* Upper-case, hex-encoded
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* See `type` for length
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## Examples
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* `{"mlat_timestamp_mhz": 120, "type": "header", "magic": "aDsB", "server_version": "https://github.com/flamingcowtv/adsb-tools#1", "server_id": "fba76102-c39a-4c4e-af7c-ddd4ec0d45e2", "mlat_timestamp_max": 9223372036854775807, "rssi_max": 4294967295}\n`
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* `{"payload": "02C58939D0B3C5", "type": "Mode-S short", "rssi": 269488144, "source_id": "f432c867-4108-4927-ba1f-1cfa71709bc4", "mlat_timestamp": 247651683709560}\n`
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* `{"payload": "A8000B0B10010680A600003E4A72", "type": "Mode-S long", "rssi": 2206434179, "source_id": "f432c867-4108-4927-ba1f-1cfa71709bc4", "mlat_timestamp": 247651683777900}\n`
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