Innovation Launch
Ask the Sun: a new way to tell a real drone from a decoy
NOVA-SOL, a passive optical method that verifies a drone from the sunlight its rotor reflects. UK patent filed, GB2624618.1.
At Physivitis we start from a simple belief: most of the bottlenecks stopping industries from scaling and securing themselves are physics problems, not engineering ones, and they are best solved with the laws of nature. Our latest innovation, NOVA-SOL, is a clear example. It answers one of the hardest questions in drone defence, is that really a drone, or a decoy? Not with a bigger camera or a cleverer classifier, but with the physics of sunlight.
The problem
A drone at a kilometre fills only a handful of pixels on a camera. At that size it looks much like a bird, a balloon, a distant aircraft, a glint off a window, or a deliberate decoy light. Today’s systems lean on an AI classifier that returns a confidence score. But a score of 0.94 is not physical proof. It tells you what the software thinks, not what the photons actually contain. In a world where cheap drones and cheaper decoys can saturate a sensor, a false alarm is expensive and a missed threat is dangerous.
The idea
A spinning propeller has a bright, mirror-like leading edge. In sunlight, that edge throws off a flash toward the observer once per blade, thousands of times a second. Here is the insight at the heart of NOVA-SOL: each of those microsecond flashes is, in effect, a tiny scan of the face of the sun. And the sun has a fingerprint. Its disc is brighter at the centre than at the rim, and it is so by a different amount in blue light than in infrared. No lamp, laser or decoy reproduces that exact two-colour signature.
NOVA-SOL reads the flashes in two colours at once and checks their shape against the sun’s own law. If the signature matches, the object genuinely carries a sunlit rotor. If it does not, NOVA-SOL rejects it. The system answers in three honest states: verified, rejected, or not yet certain.
Why it is different
Because the method compares a flash against the sun itself, the awkward unknowns cancel out. It does not need to know the range to the object, the material or reflectance of the blade, or the state of the atmosphere; all of those divide out of the measurement. That is the physics doing the work that engineering usually cannot.
Passive and silent
No radar, no radio, no jammer. Just a sensor looking at daylight, so nothing is emitted and nothing is given away.
Physics, not guesswork
Verification rests on a solar-physics invariant, not on a classifier’s confidence.
Built to resist spoofing
An artificial source would have to recreate the sun’s two-colour limb-darkening profile in a microsecond pulse.
Range, reflectance and weather independent
The quantities that defeat other optical methods cancel in the NOVA-SOL ratio.
A retrofit, not a new platform
The approach is designed to add a channel to the electro-optical turrets operators already field.
What it could unlock
For counter-drone operators at airports, critical national infrastructure, prisons and public events, NOVA-SOL points toward a calibrated, physics-grounded way to cut false alarms and to refuse to be fooled by decoys. The same principle extends naturally to rejecting sun-glint false alarms in missile-warning and infrared search-and-track systems, and to authenticating glints from objects in space. It is a single, elegant idea with a wide reach.
Where it stands, and an invitation
NOVA-SOL is patent-filed (GB2624618.1) and fully worked through in physics and simulation, including the atmospheric and surface effects that a real sky imposes. The honest next step is field measurement: confirming on real propellers, in real sunlight, what the physics and the simulations show. We are now seeking validation and licensing partners, defence primes, electro-optical sensor makers and counter-UAS integrators, to take NOVA-SOL from a filed invention to a fielded capability.
If you build or field EO/IR sensing for drone defence, we would like to talk.
Work with us
NOVA-SOL is patent filed and in simulation. We are seeking validation and licensing partners to take it from a filed invention to a fielded capability. If that is you, we would like to talk.
Start a conversationPhysivitis Ltd, Deep-Tech IP and Software for the AI and Quantum Era. NOVA-SOL is a working name. This article describes a patent-filed invention at concept and simulation stage; it does not assert measured field performance.