Dump1090_sdrplus is a Mode S decoder (see ADS-B) specifically designed for SDR devices including RTLSDR, HackRF One, Airspy and SDRplay. It is a fork of Salvatore Sanfilippo's original dump1090 with support for additional SDR devices.
The main features are:
- Robust decoding of weak messages, with dump1090 many users observed improved range compared to other popular decoders.
- Network support: TCP30003 stream (MSG5...), Raw packets, HTTP.
- Embedded HTTP server that displays currently detected aircrafts on
Google Maps. Remember to replace
YOURGOOGLEKEYingmap.htmlwith yourMaps Javascript API-enabled key to view it in browser. - Single bit errors correction using the 24 bit CRC.
- Ability to decode DF11, DF17 messages.
- Ability to decode DF formats like DF0, DF4, DF5, DF16, DF20 and DF21 where the checksum is xored with the ICAO address by brute forcing the checksum field using recently seen ICAO addresses.
- Decode raw IQ samples from file (using --ifile command line switch).
- Interactive command-line-interfae mode where aircrafts currently detected are shown as a list refreshing as more data arrives.
- CPR coordinates decoding and track calculation from velocity.
- TCP server streaming and receiving raw data to/from connected clients (using --net).
Type in the shell
sudo apt-get install librtlsdr0 librtlsdr-dev libhackrf-dev libairspy-dev libsoxr-dev
If you want to enable SDRPlay, download libraries from http://www.sdrplay.com/linuxdl.php and
chmod 755 SDRplay_RSP_API-Linux-2.13.1.run
./SDRplay_RSP_API-Linux-2.13.1.run
sudo ldconfig
make
else
make NoSDRplay=1
To capture traffic directly from your RTL device and show the captured traffic on standard output, just run the program without options at all:
./dump1090
To just output hexadecimal messages:
./dump1090 --raw
To run the program in interactive mode:
./dump1090 --interactive
To run the program in interactive mode, with networking support, and connect with your browser to http://localhost:8080 to see live traffic:
./dump1090 --interactive --net
In iteractive mode it is possible to have a less information dense but more "arcade style" output, where the screen is refreshed every second displaying all recently seen aircrafts with some additional information such as altitude and flight number, extracted from received Mode S packets.
To decode data from a file, use:
./dump1090 --ifile /path/to/binfile
The binary file can be created using rtl_sdr or hackrf_transfer (requires
conversion). File contents need to be 8-bit unsigned IQ samples at 2 Mhz sample rate.
Example with rtl_sdr:
rtl_sdr -f 1090000000 -s 2000000 -g 50 output.bin
In the example a gain of 50 is used, simply you should use the highest gain availabe for your tuner. This is not needed when calling dump1090 itself as it is able to select the highest gain supported automatically.
Example with hackrf_transfer:
hackrf_transfer -r output.sb -f 1090000000 -s 2000000 -p 0 -a 0 -l 32 -g 48
sox -r 2000000 -c 1 output.sb output.ub
In the example RX/TX RF amplifier is disabled, IF gain is set to 32dB and baseband gain is set to 48dB (80% of maximum). As opposed to RTL SDR devices, HackRF returns signed IQ values, so SoX is used to convert them to unsigned IQ values.
It is possible to feed the program with data via standard input using the --ifile option with "-" as argument.
dump1090 can be called with other command line options to set a different gain, frequency, and so forth. For a list of options use:
./dump1090 --help
By default dump1090 tries to fix single bit errors using the checksum. Basically the program will try to flip every bit of the message and check if the checksum of the resulting message matches.
This is indeed able to fix errors and works reliably in my experience, however if you are interested in very reliable data I suggest to use the --no-fix command line switch in order to disable error fixing.
In my limited experience dump1090 was able to decode a big number of messages even in conditions where I encountered problems using other programs, however no formal test was performed so I can't really claim that this program is better or worse compared to other similar programs.
If you can capture traffic that dump1090 is not able to decode properly, drop me an email with a download link. I may try to improve the detection during my free time (this is just a hobby project).
By enabling the networking support with --net dump1090 starts listening for client connections on port 30002 and 30001 (you can change both ports if you want, see --help output).
Connected clients are served with data ASAP as they arrive from the device (or from file if --ifile is used) in the raw format similar to the following:
*8D451E8B99019699C00B0A81F36E;
Every entry is separated by a simple newline (LF character, hex 0x0A).
Port 30001 is the raw input port, and can be used to feed dump1090 with
data in the same format as specified above, with hex messages starting with
a * and ending with a ; character.
So for instance if there is another remote dump1090 instance collecting data it is possible to accumulate the output to a local dump1090 instance doing something like this:
nc remote-dump1090.example.net 30002 | nc localhost 30001
It is important to note that what is received via port 30001 is also broadcasted to clients listening to port 30002.
In general everything received from port 30001 is handled exactly like the normal traffic from RTL devices or from file when --ifile is used.
It is possible to use dump1090 just as a hub using --ifile with /dev/zero as argument as in the following example:
./dump1090 --net-only
Or alternatively to see what's happening on the screen:
./dump1090 --net-only --interactive
Then you can feed it from different data sources from the internet.
Connected clients are served with messages in SBS1 (BaseStation) format, similar to:
MSG,4,,,738065,,,,,,,,420,179,,,0,,0,0,0,0
MSG,3,,,738065,,,,,,,35000,,,34.81609,34.07810,,,0,0,0,0
This can be used to feed data to various sharing sites without the need to use another decoder.
Mode S messages are transmitted at 1090 Mhz. If you have a decent antenna you'll be able to pick up signals from aircrafts pretty far from your position, especially if you are outdoor and in a position with a good sky view.
You can easily build a very cheap antenna following the istructions at:
http://antirez.com/news/46
With this trivial antenna I was able to pick up signals of aircrafts 200+ Km away from me.
If you are interested in a more serious antenna check the following resources:
- http://gnuradio.org/redmine/attachments/download/246/06-foster-adsb.pdf
- http://www.lll.lu/~edward/edward/adsb/antenna/ADSBantenna.html
- http://modesbeast.com/pix/adsb-ant-drawing.gif
With --aggressive it is possible to activate the aggressive mode that is a modified version of the Mode S packet detection and decoding. THe aggresive mode uses more CPU usually (especially if there are many planes sending DF17 packets), but can detect a few more messages.
The algorithm in aggressive mode is modified in the following ways:
- Up to two demodulation errors are tolerated (adjacent entires in the magnitude vector with the same eight). Normally only messages without errors are checked.
- It tries to fix DF17 messages trying every two bits combination.
The use of aggressive mode is only advised in places where there is low traffic in order to have a chance to capture some more messages.
The Debug mode is a visual help to improve the detection algorithm or to understand why the program is not working for a given input.
In this mode messages are displayed in an ASCII-art style graphical representation, where the individial magnitude bars sampled at 2 Mhz are displayed.
An index shows the sample number, where 0 is the sample where the first Mode S peak was found. Some additional background noise is also added before the first peak to provide some context.
To enable debug mode and check what combinations of packets you can log, use --help to obtain a list of available debug flags.
Debug mode includes an optional javascript output that is used to visualize packets using a web browser, you can use the file debug.html under the 'tools' directory to load the generated frames.js file.
The code is clearly commented in order to be easy to understand. For the diligent programmer with a Mode S specification on his hands it should be trivial to understand how it works.
The algorithms I used were obtained basically looking at many messages as displayed using a throw-away SDL program, and trying to model the algorithm based on how the messages look graphically.
If you have an RTLSDR device and you happen to be in an area where there are aircrafts flying over your head, just run the program and check for signals.
However if you don't have an RTLSDR device, or if the presence of aircrafts is very limited in your area, you may want to try the sample file distributed with the dump1090 distribution under the "testfiles" directory.
Just run it like this:
./dump1090 --ifile testfiles/modes1.bin
It is just a simple filter that will get raw IQ 8 bit samples in input and will output a file missing all the parts of the file where I and Q are lower than the specified level for more than 32 samples.
Use it like this:
cat big.bin | ./dump1090 --snip 25 > small.bin
I used it in order to create a small test file to include inside this program source code distribution.
dump1090 was written during some free time during xmas 2012, it is a hobby project so I'll be able to address issues and improve it only during free time, however you are encouraged to send pull requests in order to improve the program. A good starting point can be the TODO list included in the source distribution.
dump1090 was written by Salvatore Sanfilippo and is released under the BSD three clause license. HackRF One support was added by Ilker Temir. AirSpy support was added by Chris Kuethe. SDRplay support was added by the SDRplay team.