Can Hackers Make an Aircraft Disappear From Radar?

What if an aircraft flying at 35,000 feet suddenly vanished from a tracking screen — or worse, a flight that never existed appeared beside it?

The sky is full of invisible signals. Every second, aircraft broadcast their identity, position, altitude, and velocity to anyone with a receiver. Ground stations, other aircraft, and public flight-tracking websites all listen. It is an elegant, open system that keeps modern airspace flowing. It is also, by design, almost entirely unauthenticated.

This article looks at how researchers use Software Defined Radio (SDR) to study the security of ADS-B, GNSS/GPS, and aviation communications — what the weaknesses actually are, what they are not, and why the system is more resilient than a single spoofed display suggests.

The signals that run the sky

Three signal families matter here:

System	What it does	Security posture
ADS-B (Automatic Dependent Surveillance–Broadcast)	Aircraft broadcast their own position/ID on 1090 MHz for surveillance	No authentication, no encryption
GNSS / GPS	Satellites provide the position and timing that ADS-B reports	Civilian signals are unauthenticated and very weak at the receiver
VHF voice / datalink	Controller–pilot communication	Largely clear, legacy analog

The common thread is that these protocols were standardised decades ago, when the threat model was accidental interference, not a deliberate adversary with a laptop and a cheap radio.

ADS-B: trust by broadcast

ADS-B works because every aircraft honestly announces where it is. A receiver simply believes the message. There is no digital signature, no shared secret, and no way for a basic receiver to prove that a given message came from a real transponder on a real aircraft. The standard (RTCA DO-260B) was built for reliability and interoperability, not adversarial integrity.

That design choice is what makes spoofing conceivable: because messages aren’t signed, a receiver cannot, on its own, distinguish a genuine broadcast from a fabricated one.

GNSS/GPS: a whisper from 20,000 km

An aircraft doesn’t know where it is by magic — it computes position from GNSS satellites, then reports that position over ADS-B. Civilian GPS signals arrive extremely weak and carry no cryptographic authentication, which is why GNSS jamming (drowning the signal in noise) and spoofing (feeding a receiver false but plausible signals) are active, real-world problems, especially near conflict zones where interference has become routine.

If the input (GNSS) is manipulated, the output (a correctly-formatted ADS-B report) can be wrong while looking perfectly valid.

Where SDR comes in

A Software Defined Radio turns radio into software: instead of fixed hardware for one band, an SDR digitises a slice of spectrum and lets code do the rest. For aviation research this is transformative and entirely legitimate:

Receiving ADS-B on 1090 MHz to study message formats, coverage, and anomalies.
Monitoring the spectrum to understand interference and signal quality.
Analysing captured data to characterise how surveillance behaves under stress.

Receiving is passive, lawful, and the backbone of the entire open flight-tracking community. The picture changes completely the moment anyone transmits.

flowchart LR
  SAT[GNSS satellites] -->|position + time| AC[Aircraft]
  AC -->|ADS-B 1090 MHz| GS[Ground stations]
  AC -->|ADS-B| OTHER[Nearby aircraft]
  GS --> FUSION{Sensor fusion<br/>and validation}
  PSR[Primary radar] --> FUSION
  MLAT[Multilateration] --> FUSION
  FUSION --> ATC[Controller display]

The ghost-aircraft idea — and its hard limits

Because ADS-B messages are unauthenticated, an attacker with transmit capability could, in principle, broadcast fabricated messages: a ghost aircraft that doesn’t exist, a phantom track that drifts across a map, or altered details attached to a real flight ID. On a receiver that trusts raw ADS-B blindly — including some consumer tracking setups — these fabrications can appear real. That is the scenario the header image illustrates: a real track and a spoofed track for the same callsign.

But here is the reality check that matters, and it is the heart of this topic:

Manipulating an ADS-B display is not the same as controlling an aircraft, and it is not the same as defeating air traffic control.

Several facts collapse the gap between “a fake blip on a screen” and “a dangerous incident”:

Primary radar still exists. Primary Surveillance Radar (PSR) bounces energy off the aircraft’s physical body. It does not care what the aircraft claims. A ghost aircraft emits no radar return, so it has no skin-paint — an immediate inconsistency.
Multilateration (MLAT) checks geometry. Multiple ground receivers measure the tiny time differences of the same signal’s arrival. A spoofer transmitting from one location struggles to reproduce the arrival-time geometry of a signal genuinely coming from a point in the sky.
Sensor fusion cross-validates. Modern ATC systems correlate ADS-B with radar, MLAT, flight plans, and physics. An aircraft that teleports, exceeds its performance envelope, or has no radar return is flagged, not trusted.
Transmitting is illegal and detectable. Deliberately broadcasting on aviation frequencies is a serious crime in essentially every jurisdiction, and the transmitter’s physical location can be found through direction finding.

In short: the protocols are weak, but the system has depth. Honest research makes that distinction loudly, because overstating the threat is its own kind of misinformation.

How the system defends itself

Defence	What it catches
Primary radar (PSR)	Aircraft that claim to exist but produce no physical radar return
Multilateration (MLAT)	Signals whose arrival-time geometry doesn’t match the claimed position
Sensor fusion	Tracks that contradict radar, flight plans, or the laws of physics
Kinematic / plausibility checks	Impossible jumps, speeds, or climb rates
GNSS anti-spoofing (RAIM, multi-constellation)	Inconsistent or implausible positioning inputs
Crowdsourced validation	Large receiver networks that spot tracks only one sensor can “see”

Longer term, the community is working toward authenticated surveillance — proposals that add cryptographic integrity to position reports, and GNSS evolutions with signal authentication (such as Galileo’s OSNMA) that make spoofing the input far harder.

The ethics and the law

This field only stays valuable if it stays responsible. A few non-negotiables:

Never transmit on aviation frequencies. Receiving and analysing is research; transmitting fake signals into live airspace endangers lives and is criminal.
Test in isolation. Legitimate experimentation happens with signal generators, fully shielded RF enclosures, simulation, or recorded/synthetic data — never over the air.
Disclose responsibly. Findings go to the standards bodies, regulators, and vendors who can drive fixes — not into a how-to.

The goal of aerospace security research is not to show that the sky can be fooled. It is to make the systems we all fly on harder to fool.

The takeaway

ADS-B and civilian GNSS were built for an era of trust. SDR makes their openness visible — and, honestly examined, also reveals how much defence-in-depth surrounds them. A spoofed blip is real; a spoofed aircraft that survives radar, multilateration, and an experienced controller is a very different and far harder thing.

The sky is full of invisible signals. The interesting question isn’t whether they can be manipulated — it’s how we make the whole system notice when someone tries.