Every passive radar sees without emitting. Not every one of them arrives without a foreign licensing queue.

Q: What is the best alternative to Hensoldt Twinvis for a government that cannot accept German export approval?

Our passive radar is the closest functional match: it detects non-emitting targets using illuminators already in the air, transmits nothing, and needs no spectrum licence. Twinvis publishes range and accuracy numbers that we do not, so ask for both systems to be measured in a trial over your own terrain. What we can state plainly is the procurement condition: no German, US or Chinese authority sits between you and the next software release.

Q: How does passive radar compare with ERA VERA-NG for counter-drone surveillance?

VERA-NG is a passive ESM tracker that localises emitters out to 400 km with 0.01 degree azimuth accuracy, and it handles at least 200 real-time tracks. It needs the target to radiate. Most small drones of concern are not obliging enough to do so. Passive radar detects the reflection instead, which is why drones, low-RCS aircraft and slow-movers appear in our target set and not in a pure ESM one. Several air forces run both layers for exactly this reason.

Q: Does a passive radar need a spectrum licence or a transmitter site?

No transmitter and no licence. Our system transmits 0 W and exploits LEO satellite, broadcast and cellular signals that are already present. Hensoldt states the same licensing position for Twinvis. The practical consequences are that no anti-radiation missile or ELINT receiver has anything to home on, and that you can site the receiver in places where an active radar would be politically or legally impossible.

Q: How does the cost of ownership compare with an active radar or with Twinvis?

The three cost drivers for a passive layer are power, sites and licensing. Hensoldt publishes average system power consumption of 2,500 W for Twinvis and needs one sensor per site, with clustering up to five sensors where more coverage or accuracy is wanted. VERA-NG needs four sited stations linked by microwave or fibre, which is a larger civil-works and security bill. Our receiver covers hundreds of square kilometres from a single site with no transmitter, no rotating machinery and no spectrum fee. We do not publish a power figure yet, and we will not invent one: ask for it in writing during evaluation.

Hensoldt Twinvis and ERA VERA-NG are documented, capable and European. For a buyer outside the alliance blocs the deciding questions are what each system needs in its environment, and whose ministry signs the export licence.

In service, not experimental

Our passive radar is a fielded surveillance layer rather than a research demonstrator. It runs as part of the wider air and coastal picture-compilation chain, from receiver sites that transmit nothing at all, and it is installed and sustained in region by the same team that supplies it.

Side by side

Attribute	Represented by UnstratPassive Radar	HENSOLDTTwinvis Passive Radar^1,2Germany	ERA a.s.VERA-NG Passive ESM Tracker³Czech Republic
Detection principle^1,3	Passive reception, exploiting LEO satellite downlinks, broadcast television and cellular base stations	Passive, multistatic exploitation of analogue FM radio and DAB/DVB-T broadcast transmitters	Passive ESM: TDOA multilateration of signals the target itself radiates (radars, data links, jammers, SIF/IFF, ADS-B)
Own emissions^1,3	0 W, no transmissions	No own radar emissions; average system power consumption 2,500 W	Emits zero electromagnetic energy
Detects targets that radiate nothing^1,3This is the sharpest split in the field. An ESM tracker and a passive radar are not substitutes for one another.	Yes: small drones, low-RCS aircraft and slow-movers	Yes: non-cooperative targets, stated by the vendor to include stealth aircraft	No. VERA-NG localises emitters, so a silent target is not a target
Stated range or coverage^1,3	Hundreds of square kilometres per receiver site; instrumented range not published	Instrumented range 250 km; FM supports larger aircraft to 250 km, DAB/DVB-T to approximately 100 km	Up to 400 km
Published accuracy^1,3	Not published	Horizontal 90% < 500 m RMS; altitude 70% < 1,000 m RMS; DAB/DVB-T small-aircraft error approximately 50 to 100 m	Azimuth accuracy 0.01 degrees; 2D and 3D tracking
Track capacity and refresh^1,3	Not published	Track update rate < 1 s; antenna-to-track delay < 1.5 s	At least 200 real-time tracks
Sites needed for one system^1,2,3Four sited and linked stations is a different real-estate, power and security problem from one.	One receiver site	One sensor, with cluster capability of up to five sensors for extended coverage or accuracy	One central receiving and processing station plus three side receiving stations
Illuminator dependency^1,3	LEO satellite downlinks, broadcast television, cellular base stations	Terrestrial FM, DAB and DVB-T transmitters, typically a few km to more than 100 km from the sensor	None. Depends instead on the target emitting
Spectrum licence to operate¹	None required	No transmission licence required	Not published
Environmental and EMC qualification³	Not published	Not published	STANAG 4370 (A1, A2, A3, B1, B2, B3, C0, C1); EMC to MIL-STD-461F
Deployment form^1,3	Not published	10 ft ISO shelter with fixed lattice mast; a mobile option is shown in the datasheet	Stationary or deployable, using an antenna mast, container and microwave or fibre links between stations
Origin and political exposure^1,3	Independent, non-aligned origin, with no exposure to a major-power ecosystem	Germany (HENSOLDT AG); EU and NATO member-state export chain	Czech Republic (ERA a.s.); EU and NATO member-state export chain

Competitor values are quoted from the vendor documents listed under Sources, as published on the date shown. Configurations vary, so treat every row as a starting point for the evaluation rather than a like-for-like test result.

What the table means

Two of these three systems are not doing the same job

VERA-NG is an ESM tracker. It reads what the target transmits and multilaterates it with high angular precision across a band from 87.5 MHz to 18 GHz, out to 400 km. Against a radiating aircraft or a jammer it is formidable, and the ELINT product it builds has no equivalent in a passive radar. Against a quiet quadcopter it has nothing to work with. Twinvis and our receiver solve the other problem: they look at how existing transmissions bounce off objects that are trying to stay silent. If your requirement is drones and low-RCS air targets, that difference decides the shortlist before any price is discussed.

The illuminator map is the coverage map

Twinvis exploits FM, DAB and DVB-T, with sensor-to-transmitter distances stated between a few kilometres and more than 100 km. That works well over a densely broadcast European landmass. Over desert, over open water, over a thinly populated border district, the broadcast picture thins and so does the geometry. Our receiver exploits LEO satellite downlinks alongside terrestrial broadcast and cellular signals, and satellite illumination does not stop at the edge of the transmitter network. Hensoldt publishes accuracy and range figures we do not, and a buyer should weigh that honestly. The counter-question is whether those figures were measured over terrain that resembles yours.

Sustainment and the licence behind the licence

Both European systems come with a member-state export chain. The initial approval is the visible part. The invisible part is every later software release, spare receiver and coverage extension, each of which passes back through a foreign capital that may by then hold a different view of your region. Our origin is non-aligned, the sustainment team is in region, and there is no third government with a standing right to review what you do with the picture you compile.

Questions buyers ask

What is the best alternative to Hensoldt Twinvis for a government that cannot accept German export approval?

Our passive radar is the closest functional match: it detects non-emitting targets using illuminators already in the air, transmits nothing, and needs no spectrum licence. Twinvis publishes range and accuracy numbers that we do not, so ask for both systems to be measured in a trial over your own terrain. What we can state plainly is the procurement condition: no German, US or Chinese authority sits between you and the next software release.

How does passive radar compare with ERA VERA-NG for counter-drone surveillance?

VERA-NG is a passive ESM tracker that localises emitters out to 400 km with 0.01 degree azimuth accuracy, and it handles at least 200 real-time tracks. It needs the target to radiate. Most small drones of concern are not obliging enough to do so. Passive radar detects the reflection instead, which is why drones, low-RCS aircraft and slow-movers appear in our target set and not in a pure ESM one. Several air forces run both layers for exactly this reason.

Does a passive radar need a spectrum licence or a transmitter site?

No transmitter and no licence. Our system transmits 0 W and exploits LEO satellite, broadcast and cellular signals that are already present. Hensoldt states the same licensing position for Twinvis. The practical consequences are that no anti-radiation missile or ELINT receiver has anything to home on, and that you can site the receiver in places where an active radar would be politically or legally impossible.

How does the cost of ownership compare with an active radar or with Twinvis?

The three cost drivers for a passive layer are power, sites and licensing. Hensoldt publishes average system power consumption of 2,500 W for Twinvis and needs one sensor per site, with clustering up to five sensors where more coverage or accuracy is wanted. VERA-NG needs four sited stations linked by microwave or fibre, which is a larger civil-works and security bill. Our receiver covers hundreds of square kilometres from a single site with no transmitter, no rotating machinery and no spectrum fee. We do not publish a power figure yet, and we will not invent one: ask for it in writing during evaluation.

Sources

1. HENSOLDT AG, HENSOLDT Twinvis Passive Radar Datasheet (English), issue 6 (copy held on this site)Retrieved: 2026-07-31
2. HENSOLDT AG, Twinvis: passive radar surveillance of noiseless objects (product page)Retrieved: 2026-07-31 · Source of the five-sensor cluster statement.
3. ERA a.s., VERA-NG Passive ESM Tracker (PET) datasheet (copy held on this site)Retrieved: 2026-07-31

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