Thermal finds targets at night; identifying them needs light the eye cannot see. NIR laser illumination modules — 850 nm emitters riding co-aligned with the zoom channel — act as invisible floodlights, extending identification range deep into unlit ground where a visible spotlight would be both useless and conspicuous.
Key takeaways
- Illumination-equipped payloads use dual 0.8 W emitters at 850 ± 10 nm, paired at 8° and 30° beam angles.
- At 100 m those beams project roughly 14 m and 54 m circles: the narrow one concentrates power for zoomed identification, the wide one floods the near field for context.
- Delivered light follows inverse-square law — doubling distance quarters it — so effective range depends on zoom aperture, sensor sensitivity and target reflectivity together.
- These are Class 3B laser products under IEC 60825-1, a fundamentally different safety case from the Class 1/1M rangefinding lasers in the same pod.
On this page
Beam geometry: why two beams
A single beam cannot serve both jobs. Concentrate the power into a narrow cone and you can illuminate a target at long range through a zoomed lens, but you see nothing of the surroundings. Spread it wide and you get context at the cost of reach. The payloads that carry illumination — the LX-9B, LX-8RB and LX-8RC — carry both.
| Beam | Angle | Spot at 100 m | Purpose | Used with |
|---|---|---|---|---|
| Narrow | 8° | ≈ 14 m circle | Concentrates power for long-range identification | Zoomed in |
| Wide | 30° | ≈ 54 m circle | Floods the near field for situational context | Zoomed out |
| Both | — | — | Transitioning between search and identification | Mid zoom |
The pairing exists because the beam has to track what the zoom is doing. A narrow beam behind a wide-angle view illuminates a small bright disc in the centre of a dark frame, which is worse than no illumination at all. Matching beam to field of view is the difference between a usable image and an obvious hot spot — and it is why illumination belongs co-aligned in the gimbal rather than fixed to the airframe.
Range behaviour and the inverse-square problem
Illumination obeys the inverse-square law, and there is no engineering around it. Doubling the distance to the target quarters the light delivered. That single fact sets the practical ceiling on every NIR illumination system, regardless of emitter power.
| Factor | Effect on effective range | Under your control? |
|---|---|---|
| Distance to target | Light falls as the square of range | Yes — fly closer |
| Zoom aperture | A slower lens at maximum zoom collects less | No, once the payload is chosen |
| Sensor sensitivity | Directly sets the usable floor | No, once chosen |
| Target reflectivity | Dark clothing returns a fraction of light surfaces | No |
| Beam selection | Wrong beam wastes most of the power | Yes |
| Atmospheric conditions | Haze and rain scatter the beam back at you | No — and backscatter blinds the camera |
Backscatter is the failure operators meet first. In haze, fog or rain the beam lights up the airborne water between the aircraft and the target, and the camera sees a glowing wall. Turning the illuminator off often produces a better image than leaving it on — the same effect as high beams in fog. Fog, rain and humidity limits covers what still works.
In practice the illuminator serves the zoom channel’s identification tier after thermal has done the detection. Thermal produces a bearing in any conditions; the zoom channel plus illumination turns that bearing into an identification. That workflow is set out in night vision compared, and the sensor side in starlight and low-light imaging.
Safety class and practice
These are Class 3B laser products under IEC 60825-1. That is a materially different classification from the Class 1/1M rangefinding lasers described in laser rangefinding and geolocation, and the two are routinely confused because both are invisible and both may sit in the same pod.
- Treat the emitter like a spotlight that must never dwell on eyes at close range.
- Confirm the local regulatory position on airborne laser use before the sortie — rules vary widely and some jurisdictions require notification.
- Remember 850 nm is bright to other camera systems. Illuminating covertly is not the same as illuminating undetectably.
- Switch the illuminator off when it is not serving the current field of view; leaving it on wastes power and creates backscatter.
- Include laser state in the pre-flight and post-flight checks, so it is never left energised on the ground.
Invisible to eyes, obvious to cameras. Any CMOS sensor or night-vision device sees 850 nm clearly. If the operational requirement is genuine covertness against an observer who may also have night-vision equipment, illumination is not the tool — thermal is.
Why not just use white light
White light announces the aircraft to everyone on the ground, dazzles the subjects you are trying to observe, and carries poorly per watt at long range through a zoom lens. It also destroys the low-light adaptation of the sensor and of any crew on the ground.
NIR does the same job without any of those costs, at the price of monochrome imagery — the camera opens its IR-cut filter to use 850 nm, and colour goes with it. For identification work that trade is almost always worth making. Where colour genuinely matters and there is ambient light to work with, a starlight channel without illumination is the better answer.
Both approaches sit inside a wider night operating procedure that has to satisfy lighting and crew requirements independent of the payload — see night flight lighting and compliance. Mission-level use is covered in night security patrol and border and perimeter surveillance.
Related reading
- Starlight vs NIR vs Thermal: Drone Night Vision Compared
- Thermal vs Night Vision Drones: Which Sees What After Dark
- Thermal Drones in Fog, Rain and Humidity: What Actually Still Works
- Night Flight Lighting and Compliance for Thermal Drone Operations
- Starlight and Low-Light Imaging: Seeing in 0.01 Lux Without Thermal
- Laser Rangefinding and Target Geolocation on UAV Payloads
- Night Security Patrol Drones: Thermal and Starlight Payloads
- LX-9B — 30x zoom EO/IR payload with NIR illumination
- LX-8RB — 30x zoom payload with NIR illumination
FAQ
Is 850 nm illumination truly invisible?
To unaided eyes, effectively yes — a faint red glow may be perceptible at the emitter itself at close range. To CMOS cameras and night-vision devices it is bright, so it is covert against people, not against equipment.
Why not just use white light?
White light announces the aircraft, dazzles subjects, and carries poorly per watt at long range through zoom optics. NIR does the same job covertly, at the cost of monochrome imagery once the IR-cut filter opens.
Are the illumination and rangefinding lasers the same thing?
No. Illumination modules are Class 3B products under IEC 60825-1; measurement rangefinders are Class 1 or 1M and eye-safe in normal use. They have different safety cases even when fitted to the same payload.
Questions about the technology? Talk to our engineers — we reply within 2 business days.