Category: Airband

Monitoring Military Aircraft with an RTL-SDR Part 2

Last month we posted about monitoring and logging military ADS-B data on milaircomms.com. It turns out that there is another service at www.live-military-mode-s.eu that also does military ADS-B logging. One user of live-military-mode-s.eu has recently uploaded a tutorial showing how to use a RTL-SDR to contribute to their logs. By contributing to their service you get a username and password to access members only sections of their site.

Contribution involves running an ADS-B decoder like RTL1090, sending the decoded data to Virtual Radar Server (VRS) and then using VRS to rebroadcast the data to their Mode-S Logger software.

Some Military ADS-B Logs
Some Military ADS-B Logs

Monitoring Military Aircraft with an RTL-SDR

The military air communications monitoring enthusiasts over at milaircomms.com have been using a system involving RTL-SDRs to monitor military air traffic through ADS-B. While military aircraft generally do not transmit GPS position information like commercial aircraft do, they are still able to record live information such as the aircraft’s hex code, registration number, aircraft type, the base station location and a graph of recorded altitudes. They also log all this data showing where military aircraft have been spotted over time.

To receive this information they so far have a network of about 30 volunteers running RTL-SDR based ground stations that use their custom MilAirComms1090 software. If you want to contribute, the software is available for Windows and for Linux/Raspberry Pi.

Example of a US Coast Guard C-130 Aircraft doing Touch/Goes and Sighting History
Example Logs of a US Coast Guard C-130 Aircraft doing Touch/Goes and its Sighting History

FlightAware Introduces PiAware for use with RTL-SDR and dump1090 on a Raspberry Pi

FlightAware is an online service providing real time flight tracking. The flights are primarily tracked by volunteers who run ADS-B decoding hardware which is networked through the internet to the FlightAware servers.

Now FlightAware have written in to RTL-SDR.com to let us know about their new PiAware software which enables a Raspberry Pi running dump1090 to contribute data to the FlightAware network. Dump1090 is a popular RTL-SDR compatible ADS-B decoder program for Linux systems.

A major perk for running their software and contributing data is that FlightAware will buy you a licensed copy of PlanePlotter.

The press release provided is quoted below.

If you are running an inexpensive Raspberry Pi ADS-B receiver with dump1090 then you can install the PiAware Package from FlightAware to freely view nearby flight traffic and transmit this data to FlightAware’s tracking network.  Most aircraft within Europe by 2017 and USA by 2020 will be required to have ADS-B transmitters onboard.
FlightAware’s user-hosted worldwide ADS-B receiver network tracks about 90,000 unique aircraft per day and feeds this live data into the FlightAware website in combination with other public/private flight tracking data sources.  FlightAware has over 500 user-hosted ADS-B sites online across 60 countries, with top contributors tracking over 10,000 aircraft per day.  To see how ADS-B data is put to use, check out the FlightAware Live Map.
The PiAware installation process takes only a few minutes.  If you don’t have PlanePlotter, you can download it and then send FlightAware your installation’s serial number and we’ll buy you a license.  FlightAware will also give users a free Enterprise Account ($90/month value) in return for installing PiAware.
flightaware
FlightAware Real Time Map Example

Receiving and Decoding FLARM (Tracking Gliders, Helicopters etc) using the RTL-SDR

Over on our Facebook page, a user has let us know about the Open Glider Network project which makes use of the RTL-SDR dongle to decode FLARM. FLARM is a low cost and low power consumption ADS-B alternative which is often used by small aircraft such as gliders and helicopters for collision avoidance. With the right antenna, receiver and decoder any aircraft transmitting a FLARM signal could potentially be tracked on a map.

FLARM signals are transmitted at 868 MHz and are effectively weaker by 100-1000 times compared to standard ADS-B signals. The project recommends use of a high gain collinear antenna for receiving the weak FLARM signals. The open glider network project wiki contains information on how to set up their Linux based FLARM decoder that relies on the RTL-SDR for various embedded devices.

Once the software is up and running, the received and decoded FLARM packets can be seen on http://cunimb.fr/live/ as real time glider positions (also at http://cunimb.fr/live/3D/ in a 3D Google Earth).

FLARM Gliders shown in real time on a map
FLARM Gliders received with the RTL-SDR shown in real time on a map

Hak5: Using a Solar Powered Embedded Device with an RTL-SDR to Track Aircraft Remotely

Over on YouTube Hak5, a popular electronics enthusiast channel has uploaded a video showing their project which involves creating a remote solar powered ADS-B receiver with the RTL-SDR. They used a WiFi Pineapple which is a mini Linux based embedded computer as a remote PC and sealed it in a weather tight briefcase with a lead acid battery and solar panel. They also used a high gain directional WiFi antenna on both the transmitting and receiving ends. With this setup the WiFi Pineapple is capable of running indefinitely transmitting ADS-B data using just the solar panel and battery.

They took their setup to the top of a hill near to their office and pointed the transmitting WiFi antenna towards their offices. Then back in the comfort of their offices they were able to remotely connect to the WiFi Pineapple and start a dump1090 webserver and connect to it using Virtual Radar Server.

Solar WiFi Pineapple Briefcase, Aircraft Tracking with High Gain Point-to-Point, Hak5 1614

Monitoring Multiple AM channels with RTL-SDR Airband

A new command line program for the RTL-SDR called RTL-SDR Airband has recently been released. The program can be used to simultaneously monitor multiple AM channels per dongle. It is intended to be used with online streaming services like liveatc.net which provide live audio streams of air traffic control communications around the world.

Its features include

  • Decode multiple AM channels per dongle (within bandwidth frequency range)
  • Auto squelch and Automatic Gain Control
  • MP3 encoding
  • Stream to Icecast or SHOUTcast server
  • Low CPU usage on Windows (<4% on i5-2430m) thanks to SSE and AVX instructions
  • FFT using GPU on Raspberry Pi (50-55% CPU with default clock)
Monitoring Multiple AM Channels with RTL-SDR Airband.
Monitoring Multiple AM Channels with RTL-SDR Airband.

Hak5: Improvements to the ADS-B Antenna Drone

Previously we posted about the Hak5 teams attempt to create an ADS-B quadcopter receiver which carried a coax collinear antenna, ran the ADS-B decoder dump1090 on board and then transmitted the decoded ADS-B data back to a laptop on the ground via WiFi. Their results were poor due to various factors.

In the latest video they read comments from fans which explain why they had such poor results, then apply some of those recommendations to a second experiment. Previously they had trouble keeping the WiFi connection alive due to poor reception, so now they use a WiFi Yagi to boost the signal strength. They also reduced the number of elements on their coax collinear antenna and moved away from the broadcast RF transmitter that they were near in their last video.

There isn’t a big increase in the number of planes picked up in the second experiment but it was much more successful compared to the first.

A Better Aircraft Seeking Drone Antenna, Hak5 1613

ADS-B Decoder dump1090 now Available on Windows

Dump1090 is a popular command line ADS-B decoder which many people believe has superior decoding performance compared to other decoding software. Previously it has only been available for Linux and Mac operating systems, however recently it has been updated with a Windows command line version. The most up to date branch of dump1090 can be downloaded from GitHub here.

To install dump1090 on Windows follow these steps:

  1. Download the dump1090 zip file from the GitHub download link.
  2. Download the official RTL-SDR Windows release from http://sdr.osmocom.org/trac/attachment/wiki/rtl-sdr/RelWithDebInfo.zip.
  3. Copy the libusb-1.0.dll, rtlsdr.dll and pthreadVC2-w32.dll files from the official RTL-SDR Windows release zip file to the dump1090 folder. Rename pthreadVC2-w32.dll to pthreadVC2.dll.
  4. Double click on dump1090.bat.

The batch file starts a dump1090 webserver which can be viewed in any browser by going to http://localhost:8080. You may wish to edit the batch file and add extra flags such as –aggressive and/or –fix to improve decoding.

Modesdeco: Now Supports Simultaneous Reception of Mode S and Mode A/C

Modesdeco is a Windows/Linux/OSX/RPi compatible command line ADS-B Mode S decoder built for the RTL-SDR. It natively supports the BaseStation format and so can be used with the BaseStation software without the need for com port converters.

Modesdeco has recently been updated to allow for the simultaneous reception of Mode S and Mode A/C. Mode S provides location data for ADS-B while Mode A provides an identification code and Mode C provides the aircraft’s pressure altitude.

Effect of a Filter on RTL-SDR ADS-B Reception

Over on YouTube user Adam Alicajic has posted a video showing the effect of a filter tuned for 1090 MHz used on ADS-B reception. Adam switches the filter in an out showing the difference in the number of received ADS-B frames. With the filter enabled he is able to receive around 1200 messages per second and without only around 800 messages per second.

A filter (aka preselector) can help to reduce out of band interference from strong signals.

DVB-T dongle receiving the ADS-B using the filter