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https://github.com/mutability/dump978
Experimental demodulator/decoder for UAT on 978MHz
https://github.com/mutability/dump978
Last synced: about 2 months ago
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Experimental demodulator/decoder for UAT on 978MHz
- Host: GitHub
- URL: https://github.com/mutability/dump978
- Owner: mutability
- License: gpl-2.0
- Archived: true
- Created: 2015-01-24T14:43:16.000Z (over 9 years ago)
- Default Branch: master
- Last Pushed: 2023-08-03T03:00:07.000Z (about 1 year ago)
- Last Synced: 2024-06-08T21:32:27.636Z (4 months ago)
- Language: C
- Size: 172 KB
- Stars: 170
- Watchers: 38
- Forks: 80
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
README
# dump978
Experimental demodulator/decoder for 978MHz UAT signals.
# This repository is unmaintained
Please use https://github.com/flightaware/dump978 instead of this repository.
## Demodulator
dump978 is the demodulator. It expects 8-bit I/Q samples on stdin at
2.083334MHz, for example:
````
$ rtl_sdr -f 978000000 -s 2083334 -g 48 - | ./dump978
````
It outputs one one line per demodulated message, in the form:
````
+012345678..; this is an uplink message
-012345678..; this is a downlink message
````
For parsers: ignore everything between the first semicolon and newline that
you don't understand, it will be used for metadata later. See reader.[ch] for
a reference implementation.
## Decoder
To decode messages into a readable form use uat2text:
````
$ rtl_sdr -f 978000000 -s 2083334 -g 48 - | ./dump978 | ./uat2text
````
## Sample data
Around 1100 sample messages are in the file sample-data.txt.gz. They are the
output of the demodulator from various RF captures I have on hand. This file
can be fed to uat2text etc:
$ zcat sample-data.txt.gz | ./uat2text
When testing, this is much easier on your CPU (and disk space!) than starting
from the raw RF captures.
## Filtering for just uplink or downlink messages
As the uplink and downlink messages start with different characters, you can
filter for just one type of message very easily with grep:
````
# Uplink messages only:
$ zcat sample-data.txt.gz | grep "^+" | ./uat2text
# Downlink messages only:
$ zcat sample-data.txt.gz | grep "^-" | ./uat2text
````
## Map generation via uat2json
uat2json writes aircraft.json files in the format expected by *my fork* of
[dump1090](https://github.com/mutability/dump1090)'s map html/javascript.
To set up a live map feed:
1) Get a copy of [this dump1090 repository](https://github.com/mutability/dump1090).
We're going to reuse its mapping html/javascript:
````
$ git clone https://github.com/mutability/dump1090 dump1090-copy
````
2) Put the html/javascript somewhere your webserver can reach:
````
$ mkdir /var/www/dump978map
$ cp -a dump1090-copy/public_html/* /var/www/dump978map/
````
3) Create an empty "data" subdirectory
````
$ mkdir /var/www/dump978map/data
````
4) Feed uat2json from dump978:
````
$ rtl_sdr -f 978000000 -s 2083334 -g 48 - | \
./dump978 | \
./uat2json /var/www/dump978map/data
````
5) Go look at http://localhost/dump978map/
## uat2esnt: convert UAT ADS-B messages to Mode S ADS-B messages.
Warning: This one is particularly experimental.
uat2esnt accepts 978MHz UAT downlink messages on stdin and
generates 1090MHz Extended Squitter messages on stdout.
The generated messages mostly use DF18 with CF=6, which is
for rebroadcasts of ADS-B messages (ADS-R).
The output format is the "AVR" text format; this can be
fed to dump1090 on port 30001 by default. Other ADS-B tools
may accept it too - e.g. VRS seems to accept most of it (though
it ignores DF18 CF=5 messages which are generated for
non-ICAO-address callsign/squawk information.
You'll want a pipeline like this:
````
$ rtl_sdr -f 978000000 -s 2083334 -g 48 - | \
./dump978 | \
./uat2esnt | \
nc -q1 localhost 30001
````