DIY Passive Radar System Verifies ADS-B Transmissions

April 29, 2024 by Bryan Cockfield 5 Comments

Like most waves in the electromagnetic spectrum, radio waves tend to bounce off of various objects. This can be frustrating to anyone trying to use something like a GMRS or LoRa radio in a dense city, for example, but these reflections can also be exploited for productive use as well, most famously by radar. Radar has plenty of applications such as weather forecasting and various military uses. With some software-defined radio tools, it’s also possible to use radar for tracking aircraft in real-time at home like this DIY radar system.

Unlike active radar systems which use a specific radio source to look for reflections, this system is a passive radar system that uses radio waves already present in the environment to track objects. A reference antenna is used to listen to the target frequency, and in this installation, a nine-element Yagi antenna is configured to listen for reflections. The radio waves that each antenna hears are sent through a computer program that compares the two to identify the reflections of the reference radio signal heard by the Yagi.

Even though a system like this doesn’t include any high-powered active elements, it still takes a considerable chunk of computing resources and some skill to identify the data presented by the software. [Nathan] aka [30hours] gives a fairly thorough overview of the system which can even recognize helicopters from other types of aircraft, and also uses the ADS-B monitoring system as a sanity check. Radar can be used to monitor other vehicles as well, like this 24 GHz radar module found in some modern passenger vehicles.

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Hackaday Links: February 18, 2024

February 18, 2024 by Dan Maloney 17 Comments

So it turns out that walking around with $4,000 worth of hardware on your head isn’t quite the peak technology experience that some people thought it would be. We’re talking about the recently released Apple Vision Pro headset, which early adopters are lining up in droves to return. Complaints run the gamut from totally foreseeable episodes of motion sickness to neck pain from supporting the heavy headset. Any eyeglass wearer can certainly attest to even lightweight frames and lenses becoming a burden by the end of the day. We can’t imagine what it would be like to wear a headset like that all day. Ergonomic woes aside, some people are feeling buyer’s remorse thanks to a lack of apps that do anything to justify the hefty price tag. The evidence for a wave of returns is mostly gleaned from social media posts, so it has to be taken with a grain of salt. We wouldn’t expect Apple to be too forthcoming with official return figures, though, so the ultimate proof of uptake will probably be how often you spot one in the wild. Apart from a few cities and only for the next few weeks, we suspect sightings will be few and far between.

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Is An ADS-B Receiver The Solution For Drone Pilots?

April 27, 2023 by Jenny List 44 Comments

Over the years here at Hackaday, we’ve covered a range of stories about the ongoing panic surrounding drone flights. From plastic bags reported as drone incidents through to airports closed with no evidence of drones being involved, it’s clear that drone fliers are an embattled group facing a legal and aeronautical establishment that seems to understand little about them or their craft.

It sometimes seems to be a no-win situation for fliers, but perhaps [XJet] has something which might improve matters. He’s published a video showing off a portable ADS-B receiver which could be used by drone pilots to check for any aircraft in the vicinity and perhaps more importantly allow the drone community to take the moral high ground when problems occur.

The receiver isn’t particularly special, being a Raspberry Pi with LCD screen and an RTL-SDR receiver in a nice 3D printed enclosure. He says he’ll be publishing all software and build details in due course. But it’s the accessibility which makes it such a good idea, instead of being a very expensive safety device it’s a receiver that could probably be made with a less powerful Pi for under $100.

There is of course a flaw in the plan, that not all pilots are concerned enough for their safety to fit an ADS-B transponder to their aircraft, and so are invisible to both the thus-equipped drone pilot and air traffic control alike. This puts the onus on pilots to consider ADS-B an essential, but from the drone flier’s point of view we’d consider that a spotter should be part of their group anyway.

Curious what the fuss is about? Let us take you on a journey.

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Real Radar Scope CRT Shows Flights Using ADS-B

April 15, 2023 by Dan Maloney 12 Comments

Real-time flight data used to be something that was only available to air traffic controllers, hunched over radar scopes in darkened rooms watching the comings and goings of flights as glowing phosphor traces on their screens. But that was then; now, flight tracking is as simple as pulling up a web page. But where’s the fun in that?

To bring some of that old-school feel to his flight tracking, [Jarrett Cigainero] has been working on this ADS-B scope that uses a real radar CRT. As you can imagine, this project is pretty complex, starting with driving the 5FP7 CRT, a 5″ round-face tube with a long-persistence P7-type phosphor. The tube needs about 7 kV for the anode, which is delivered via a homebrew power supply complete with a custom flyback transformer. There’s also a lot going on with the X-Y deflection amps and beam intensity control.

The software side has a lot going on as well. ADS-B data comes from an SDR dongle using dump1090 running on a Raspberry Pi 3B. The latitude and longitude of each plane within range — about 5 nautical miles — is translated to vector coordinates, and as the “radar” sweeps past the location, a pip lights up on the scope. And no, you’re not seeing things if you see two colors in the video below; as [TubeTime] helpfully explains, P7 is a cascade phosphor that initially emits a bright-blue light with some UV in it, which then charges up a long-persistence green phosphor.

Even though multicolored icons and satellite imagery may be more useful for flight tracking, we really like the simple retro look [Jarrett] has managed to pull off here, not to mention the hackery needed to do it.

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ADS-B Exchange Sells Up, Contributors Unhappy

January 26, 2023 by Jenny List 62 Comments

In the news among aviation enthusiasts, the ADS-B data aggregation and aircraft tracking site ADSB-Exchange has been sold by its founder to JETNET for a reported $20,000,000. This type of routine financial news is more at home in the business media than on Hackaday, but in this case there’s something a little different at play. ADS-B Exchange is a community driven site whose data comes from thousands of enthusiasts worldwide connecting their ADS-B receivers to its feed API. The sale to a commercial flight data company has not gone down well with this community who are unsurprisingly unimpressed that their free contributions to the website have been sold.

This certainly isn’t the first time a site built on community data has flipped into big business, and while it’s unclear whether JETNET will do a full CDDB and boot out anyone not paying to play, we can understand the users feeling that their work has been sold from under them. On the other hand, how many of us can truly claim their open source beliefs wouldn’t start to buckle once somebody slides a $20m check across the table?

It’s evidently too late for anyone aggrieved by their ADS-B data being sold, but perhaps there’s something else to think about here. We have an established way to recognize open source software in the many well-known software libre licences, but we don’t for crowd-sourced data. Perhaps it’s time for the open-source community to consider this problem and come up with something for future sites like ADS-B Exchange whatever field they may be in, a licence which clearly defines the open terms under which contributors provide the data and those under which site owners can use it. Otherwise we’ll be here again in a few years writing about another aggrieved community, and we think that doesn’t have to happen.

It’s A Bird! It’s A Plane! It’s… A Live Air Traffic Plane Spotting Simulation

July 12, 2022 by Ryan Flowers 5 Comments

Plane spotting has been a hobby of aviation enthusiasts for generations. Hanging out by the airport, watching aircraft come and go, maybe even listening to Air Traffic Control on a scanner from your local Radio Shack. Yep- we’ve been there, and it can be a lot of fun! But how can those of us who don’t live near a major controlled airport keep up on the action? As demonstrated by the [Information Zulu] YouTube channel’s Live Stream, seen below the break, the action may be closer than you think!

By using publicly available information, software, and some ingenuity, [Information Zulu] has created a live simulation of Los Angeles International Airport (LAX) for your simulated plane spotting pleasure. Aircraft positional data is gained through an ADSB receiver and piped into a the flight simulator software with a Traffic Injection Addon, and the simulator itself is used to properly place aircraft, set the weather, and even the correct aircraft types and liveries. Setting off the illusion of a real plane spotting adventure is the live Air Traffic Control radio chatter!

We love the creativity that went into not just making all of the software available, but in combining it into a cohesive product that can be viewed 24/7 on YouTube that, if you squint just right, could be mistaken for a view of the real thing.

If you’re not familiar with ADSB and how it’s used to track aircraft in such a way that anybody can receive it with the right equipment, check out this beginner’s course on ADSB from a few years back!

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Tracking Boats And Ships In Real Time At The Same Time

October 22, 2020 by Bryan Cockfield 15 Comments

Software-defined radio came on the hacker scene in a big way less than a decade ago thanks to the discovery that a small USB-based TV tuner dongle could be used for receiving all kinds of radio transmissions. Two popular projects from that era are tracking nearby airplanes and boats in real time. Of course, these projects rely on different frequencies and protocols, but if you live in a major port city like [Ian] then his project that combines both into a single user interface might be of interest.

This project uses an RTL-SDR dongle for the marine traffic portion of the project, but steps up to a FlightAware Pro dongle for receiving telemetry from airplanes. Two separate antennas are needed for this, and all of the information is gathered and handled by a pair of Raspberry Pis. The Pis communicate with various marine and air traffic databases as well as handles the custom user interface that knits both sets of information together. This interface was custom-built from a previous project of his and was repurposed slightly to fit the needs of this one.

This is a great project that goes into a lot of interesting detail about how the web traffic moves and how the UI works, so even if you’re not into software-defined radio it might be worth a look. However, it’s also worth noting that it hasn’t been easier to set up a system like this thanks to the abundance and low price of RTL-SDR dongles and the software tools that make setting them up a breeze.