Over on YouTube user hpux735 has uploaded a video where he explores the feasibility of receiving VOR radio navigation signals using GNU Radio and an RTL-SDR. VOR is an acronym for VHF Omni Directional Radio Range and is an older method of navigation used by aircraft which is quickly being made redundant due to GPS navigation. VOR uses two signals, one master omnidirectional signal and one rotating directional signal. By doing some calculations on the received phase of these two signals it is possible to determine the angle of the aircraft from the transmitter.
In the video hpux735 explains and discusses the VOR signal and also shows how to use these signals for navigation with an RTL-SDR and GNU Radio flowchart. To receive the VOR signal he uses an RTL-SDR to record the VOR signal while he drives around with a car. Then later he uses his GNU Radio program to generate a plot that shows when he is moving and in which direction.
hpux735 has also uploaded some supplemental material over on his blog. In the future he hopes to correlate his VOR results with GPS coordinates that he will take whilst actually flying around.
Simon’s project works by using the RTL-SDR connected to the Raspberry Pi as an ADS-B receiver. From the ADS-B signals the current coordinates of nearby aircraft can be determined. Then by using some coordinate math, the Raspberry Pi can be told to point its camera in the direction of the aircraft. As well as videoing the passing aircraft, the Raspberry Pi also overlays text on to the video showing information such as flight number, source and destination airports, aircraft type, elevation and distance and date of observation.
In addition to all that, his software also automatically uploads the recorded videos onto his website. Here you can see the latest and closest video captures his system has performed.
On this episode of Hak5, a popular YouTube technology channel, Shannon shows two Android based ADS-B RTL-SDR apps that we have mentioned on this blog previously. One is “ADS-B on USB SDR RTL” and the other is Avare ADS-B. Both are ADS-B apps that will display real time airplane positions on a map.
To run these apps you need a RTL-SDR dongle, a USB OTG cable and an Android phone.
Cellular Testing Tools and Mobile SDR Apps, Hak5 1708
Japanese blogger and RTL-SDR experimenter ttreftech has had an ADS-B front end kit (In Japanese, use Google Translate) consisting of a low noise amplifier (LNA) and SAW filter available for sale in Japan for a few months now. The LNA helps to push weak signals through the coax feed line and the SAW filter is a bandpass filter that helps to remove interference outside of the 1090 MHz ADS-B region. If you are interested in building your own version, ttrftech has also posted a schematic. Another recent post about the front-end can be found here.
Another Japanese blogger, “pup” has posted about his results with the ADS-B front end kit (Also in Japanese, use Google Translate). His results show that the front end does significantly improve ADS-B reception. The image below shows an ADS-B signal with the front end turned off (top) and with it turned on (bottom). Pup has also posted a video showing the kit and its performance on HDSDR.
SonicGoose writes that the reason that many PlanePlotter users are moving away from the simpler GUI based RTL1090 ADS-B decoder is because dump1090 provides better raw data to use for multilateration. Multilateration is a technique supported by PlanePlotter which used data shared from multiple receivers to determine the location of an aircraft, even if that aircraft is not transmitting location information.
Over on the Google Play store there is a new (released July 2014) RTL-SDR ADS-B Android app available for purchase called “ADS-B Receiver”. This app allows you to with the aid of an RTL-SDR and USB OTG cable, display live aircraft ADS-B data on your Android phone. This app can also be used to display the live ADS-B data in another app called “Avare”, which provides offline FAA aviation charts and other pilot tools on a Android phone.
The app can be downloaded as a trial version with a fixed limit on the number of packets allowed to be received, or the pro version for around $1.99 USD with no limits.
Previously on this blog we mentioned another similar RTL-SDR Android ADS-B app called “ADS-B on USB SDR RTL“.
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.
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.