Passive RF — low-altitude airspace

≈ 300 m AGL — typical surveillance floor

BRG 042° · EL 11.9°RSSI −74 dBm · 296 m AGL

Airspace awareness, from the first signal.

Guardian1.40 kmGround datum
Fig. 01 — Low-altitude volume, cross-section · vertical exaggerationBearing 042° · synthetic reference

We build indigenous radio-frequency sensing for low-altitude airspace. Guardian, our first system, detects, classifies and tracks unmanned aircraft by the signals they and their operators emit.

01

The gap

Why low-altitude airspace became the least defended volume in modern security.

Radar was built for aircraft. It was never built for a two-kilogram airframe moving at forty kilometres an hour below the treeline, and the physics has not changed to accommodate one.

The result is a volume of airspace that is trivial to enter and difficult to observe, over borders, installations and cities where the consequences of entering it are not trivial at all.

  • 01

    Accessible

    Capable unmanned aircraft are commodity hardware. They are bought online, modified in a workshop, and flown by anyone — which removes the resource barrier that used to limit who could threaten an airspace.

  • 02

    Unresolved

    Small, slow and low is the exact profile conventional radar was tuned to discard as clutter. Air defence resolves the sky above a few hundred metres in detail, and very little beneath it.

  • 03

    Imported

    Most counter-drone capability fielded in India today originates abroad, carrying the cost, the lead time and the dependency that comes with it.

02

The pipeline

From radio emission to an operational picture. Five stages, all running in real time, all on the unit.

2.4002.4202.4402.4602.483 GHz
Fig. 012.4 GHz ISM · 20 MHz span · OFDM downlink with hopping control linkSynthetic reference render
  • 01

    Detect

    Wideband monitoring of the bands that drone control, telemetry and video links occupy. The sensing is passive: Guardian transmits nothing, so it cannot be located by what it does.

  • 02

    Classify

    Signal features and learned RF signatures separate a control link from a Wi-Fi router, and one airframe family from another. Emitters that are not of interest are discarded before they reach the operator.

  • 03

    Localise

    A direction-finding antenna array and phase-based processing give direction of arrival, referenced to true north through GNSS. Two or more units triangulate a position — including the operator's.

  • 04

    Track

    Successive bearings accumulate into a trajectory: heading, behaviour over time, and the beginnings of an assessment of intent rather than a single alarm.

  • 05

    Present

    One operational picture, on a map, on the unit's own display or an operator laptop — with an interface to the command systems already in place.

Fig. 02Instantaneous spectrum · emitters of interest isolatedSynthetic
Fig. 03Bearing 042°±9° conf.

03

Guardian

The first system, and the sensing layer everything after it is built on.

A passive radio-frequency detection, direction-finding and tracking unit.

Guardian listens across the bands drones use, identifies which emitters matter, works out where they are, and follows them. It runs standalone at a single site or as one node in a network that triangulates position across units.

Sensing
Passive wideband RF, direct sampling at the antenna
Function
Detection, classification, direction finding, tracking
Reference
GNSS position and time; bearings referenced to true north
Deployment
Standalone unit, or networked for triangulation
Interface
On-unit display, operator application, API integration
Status
In development Prototype
Guardian in detail

04

Principles

Constraints set at the start, applied to every design decision since.

  • 01

    In-house IP

    Critical technology is developed rather than imported. Sensing, signal processing and autonomous decision-making are built as internal capability, because that is the part that cannot be bought back later.

  • 02

    Autonomous operation

    Detection, classification and tracking run without a human in the loop. Operator attention is a scarce resource and should be spent on decisions, not on watching a spectrum.

  • 03

    Modular architecture

    Every subsystem operates independently or as part of a larger network, so an individual layer can be upgraded without redesigning the system around it.

  • 04

    Scalable deployment

    The same unit serves a single site or a distributed sensor network. Coverage grows by adding nodes, not by replacing the architecture.

  • 05

    Compact and efficient

    Hardware is designed to be light and power-efficient enough for mobile platforms, remote installations and field operation.

  • 06

    Cost efficiency

    A system that cannot be afforded in quantity cannot protect a border. Cost is treated as an engineering requirement, not an outcome.

  • 07

    Interoperability

    Open interfaces to existing command, control and defence infrastructure. Guardian is designed to make other systems better informed, not to replace them.

05

Applications

Wherever an airspace has a boundary and someone is accountable for it.

Border and perimeter

Persistent watch over restricted approaches.

Military operations

Early warning and battlefield situational awareness.

Critical infrastructure

Airports, ports, power generation, oil and gas.

Government installations

Sensitive sites and secure campuses.

Events and VIP security

Temporary cover for public gatherings.

Sensor integration

Cueing for radar, EO/IR and acoustic systems.

Deployment contexts

06

Contact

Direct, and answered by an engineer.

If you are accountable for airspace you cannot currently see, we should talk.