DJI’s AeroScope is the most widely deployed drone detection system in the world, and in 2026 it is still the first product many buyers evaluate. This article is our working notes on how it works, what it covers, and what the alternatives look like — written for buyers comparing options, with every claim sourced.

What AeroScope actually does

AeroScope is a passive RF receiver. It listens to the communication link between a DJI drone and its remote controller and decodes it: position, altitude, speed, direction, serial number and take-off location, per DJI’s product page, with identification in as fast as two seconds. DJI claims monitoring of up to 50 km under ideal conditions; integrator deployments typically land between a 3-mile and 16-mile radius depending on antenna configuration. (Sources: dji.com/aeroscope; airsight.com deployment data — vendor-reported.)

The limitation that decides everything

AeroScope decodes the DJI protocol. That means it sees DJI drones — and nothing else. Critics including AeroDefense have made this point for years: DIY builds, other manufacturers, and modified aircraft are invisible to it. DJI’s counter-argument is market share; roughly nine in ten consumer drones are DJI, so covering DJI covers most of the hobby traffic. Both things are true, and which one matters depends on your threat model. A prison worried about contraband drops flown on a 500-euro home-built quad is not protected by a DJI-only sensor.

How we evaluated alternatives

Method, stated up front: we have not run a head-to-head field trial of every product named here. This comparison is built from published vendor material, regulatory filings and the evidence labels on our receiver comparison page — checked September 2026. Where a number is vendor-reported, treat it as a claim, not a measurement.

The alternatives, by detection layer

• Remote ID receivers — receive the standardised broadcast that most drones sold since 2024 must carry (US Part 89, EU direct remote ID). Brand-agnostic: a non-DJI drone that broadcasts is visible. Budget: roughly $129–2,500 per node.
• RF spectrum sensors — detect any transmitting drone, including FPV builds and modified aircraft, across 2.4/5.8 GHz and beyond. The trade is cost ($3,500–15,000) and a higher false-alarm rate on shared bands.
• Radar — sees aircraft that transmit nothing at all, at the highest cost and integration effort. Beyond our comparison scope; we refer to specialists.

Where buyers go wrong

Three failure patterns we keep seeing. First, buying for the drones that exist today and not for the one that shows up next month — a DJI-only sensor and a Remote ID receiver fail in opposite ways. Second, taking the 50 km figure as a deployment figure; ideal conditions do not survive a prison fence line. Third, skipping the walk-test: no coverage claim survives contact with your actual site.

If your concern is…	Best-fit layer	Why
DJI hobby traffic near an airport	DJI-protocol or RID receiver	Cheapest coverage of the dominant fleet
Non-DJI and unknown drones	RID receiver	Standardised broadcast, brand-agnostic
FPV / modified / silent aircraft	RF spectrum sensor	Detects the transmission, not the paperwork
Full perimeter, no assumptions	RID + RF combined	Layers cover each other’s blind spots

Next step: the receiver comparison lists candidates with sources and dates, and the free screening tells you within one business day which layer your site actually needs.

Content last reviewed: 2026-09-11. Sources: dji.com/aeroscope (vendor-reported); airsight.com; AeroDefense blog; COPTRZ market-share commentary.

Drones over UK prisons stopped being a curiosity years ago. This guide collects what is publicly known about the scale of the problem, what detection technology can and cannot do about it, and how we think a prison should approach its first deployment — with the honest caveats in place from the start.

The scale, in numbers we can source

The UK government has reported 1,712 drone incidents at prisons in a single year — a 43% rise on the previous period — covering sightings, disruptions and confirmed contraband attempts. (Source: GOV.UK prison drone statistics; vendor- and government-reported, checked September 2026.) Behind the number sits a simple economics problem: a drone can deliver contraband worth thousands of pounds in a thirty-second hover, and the alternative — corrupted staff or elaborate smuggling — costs more and carries more risk for the criminals.

What detection can actually see

A prison is a mixed-threat airspace, and that is the crux. Machines flown by organised groups are often home-built FPV quads: no Remote ID broadcast, no registration, nothing a standard receiver can hear. Consumer drones doing opportunistic flights — photography, curiosity — usually do broadcast. Our working numbers, all vendor-reported and documented on the receiver comparison: Remote ID receivers start around $129 per node; RF-spectrum sensors, which hear the FPV traffic, start around $3,500. Radar exists for full coverage and costs an order of magnitude more.

How we evaluated approaches

We have not installed detection at a prison ourselves — our role is selection advisory, and this guide is a synthesis of published incident data, vendor documentation and the survey discipline described in our site survey checklist. Everything we recommend below is buildable by an in-house team; the pilot criteria are the same ones we would accept in a procurement.

A staged deployment that holds up

• Phase 1 — baseline (weeks 1–4): one RID receiver on the main approach, logging 24/7. Cost: low. Purpose: learn what your airspace actually contains — most sites are surprised.
• Phase 2 — RF layer (months 2–3): add RF-spectrum monitoring on the approach corridors if the baseline shows silent traffic or if the threat assessment says it will.
• Phase 3 — response integration: alerts into the existing control room workflow, correlation across nodes, and a documented protocol for what happens on a confirmed detection.
• Phase 4 — validation: an authorised walk-test with a known drone on a planned grid, detection logged against GPS truth, gaps on the map. No deployment is “done” without it.

The failure modes to design out

Detections without a response protocol become noise within weeks. Systems bought on coverage promises collapse at the first wall. Budgets that cover hardware but skip validation leave you unable to prove the system works on the day it matters. And a procurement that ignores the silent-FPV problem — because a datasheet said “drone detection” — is the most expensive failure of all, because it feels solved until the night it is not.

Where to go next: our prison detection page carries the full scenario breakdown, the deployment guide covers siting and validation, and the free screening is the fastest way to test our judgement before any money moves.

Content last reviewed: 2026-09-11. Sources: GOV.UK prison incident statistics (1,712 / +43%); vendor documentation, checked September 2026. Not legal advice.

“Which drone detection technology should I buy?” is the wrong first question. The right one is “what does my site need to see, and what can it afford to miss?” This article walks through that decision site-type by site-type, with budgets, evidence labels and the combinations that actually make sense. It goes deeper than our earlier primer on the three technologies — this one is for people close to a purchase.

The three layers, one line each

Remote ID (RID) receivers hear the standardised broadcast that most drones sold since 2024 must carry: identity, position, take-off point. RF spectrum sensors hear any transmitter — including FPV builds and modified aircraft that broadcast nothing. Radar sees airframes whether they transmit or not, at the highest cost. Prices we quote across the site, all vendor-reported: RID $129–2,500 per node, RF $3,500–15,000, radar from roughly $50,000 upward for a usable installation.

How we structured this comparison

Method: we match detection layers against site types using three inputs — the threat models that dominate each site category, the published capability and cost data on our receiver comparison, and the survey discipline in our checklist. We do not score radar (outside our advisory scope) beyond noting where it belongs. Treat every budget as vendor-reported; treat the mapping as our judgement, not physics.

Site type by site type

• Prisons and secure facilities — the confirmed threat is contraband drops, often flown on home-built quads. RID alone undercovers; the RF layer is not optional. Start RID (cheap baseline), add RF on approach corridors.
• Airports and airspace — the fleet is mostly compliant consumer and commercial aircraft. RID receivers carry most of the load; RF and radar are regulator-grade additions. Your aviation authority will have opinions — involve them early.
• Events and stadiums — short deployments, dense RF, heavy media drones that do broadcast. RID-first works; RF earns its cost only for A-list threat profiles. Renting beats buying for one-off events.
• Critical infrastructure — mixed fleet, long perimeter, 24/7 operation. The RID + RF combination is the honest default; budget for two nodes minimum and a validation walk-test.
• Law enforcement — you need identification for response, which makes RID’s decoded identity (serial, operator position) uniquely valuable; RF adds the silent-aircraft picture. Evidence handling rules push toward logged, timestamped data — both layers provide it.

Where buyers go wrong

The recurring failure is buying the impressive layer instead of the correct one: radar dreams on a RID budget, or an RF sensor deployed where every detection is a false alarm because the site’s own Wi-Fi drowns 2.4 GHz. The second failure is skipping phase zero — two weeks of baseline logging answers more questions than any datasheet.

Site	Start with	Add if	Skip for now
Prison	RID baseline + RF	Radar at state level	Radar-only
Airport	RID receiver grid	RF for known silent traffic	DIY anything
Event	RID (rented)	RF for A-list events	Purchases
Infrastructure	RID + RF two-node	Correlation service	Single-layer promises
Law enforcement	RID for identification	RF vehicle unit	Fixed install before pilots

Where to go next: run your site through the survey checklist, compare hardware on the receiver table, or hand the question to us with the free screening.

Content last reviewed: 2026-09-11. Budgets are vendor-reported, checked September 2026. This is advisory content, not a quotation.

“Can I legally detect drones flying over my property?” We get this question weekly, and the short answer in the US, UK and EU is: receiving is fine, jamming is a crime, and the data you log has its own rules. This article maps the lines — it is not legal advice, and the regulations deserve a lawyer’s read before you act on them.

Receiving is (mostly) legal

Passive detection — listening to what a drone broadcasts or transmits — is generally lawful. Remote ID broadcasts are, by design, public signals: regulators built the system precisely so that third parties could receive them. A RID receiver or an RF sensor that only listens stays on the right side of interception law in the jurisdictions we advise on. Radar is different in kind: transmitting energy into the airspace can trigger aviation and planning rules that a receiver never touches, which is one more reason it sits outside our advisory scope.

Jamming is a crime — full stop

Everything that transmits to stop a drone — jammers, spoofers, force-landing devices — is illegal to operate for almost everyone in the US, UK and EU. In the United States the FCC treats jamming as a violation of the Communications Act with substantial penalties; in the UK the Wireless Telegraphy Act does the same work. Only a handful of government agencies hold exemptions. Buyers frequently ask us “and then it lands it, right?” — and the answer is that the kit which does that is not something a private site can legally switch on. (Sources: FCC jammer enforcement guidance; Ofcom/WTA framework.)

The data you log is the quiet trap

A detection log is not anonymous. A Remote ID record ties a serial number to a position and a timestamp; correlated over time, it traces an individual pilot’s home and habits. Under GDPR in the EU, and under comparable privacy expectations elsewhere, that makes detection logs personal data — with retention limits, access control and a lawful basis attached. We say this as advisers, not lawyers: the detection project that forgets data protection usually discovers it in the worst possible meeting. Our own handling is published on the privacy page.

How we evaluated the rules

Method: this summary rests on the published positions of the FCC, Ofcom and EU data-protection guidance, checked September 2026, plus the Regulatory texts themselves (14 CFR Part 89 for the US, the UK CAA framework for Britain). We are technologists, not a law firm — where your deployment touches aviation authority permissions, security-of-persons exemptions or employment law, get professional advice.

Action	US	UK / EU
Receiving broadcasts (RID/RF listening)	Generally lawful	Generally lawful
Jamming / spoofing / force-landing	Illegal (FCC)	Illegal (Ofcom / WTA)
Logging detection data	Fine; mind data care	Personal data under GDPR
Sharing logs publicly	Careful	Lawful basis required

Where to go next: the survey checklist includes the data-handling check most deployments skip, and the free screening is the place to surface compliance questions before they become procurement questions.

Content last reviewed: 2026-09-11. Sources: FCC jammer guidance; Ofcom / Wireless Telegraphy Act framework; 14 CFR Part 89; GDPR guidance. Not legal advice.

The US Army has committed up to $99 million to a spectrum analyzer that weighs less than a water bottle. The contract went to Heaviside Industries Inc. of Marina del Rey, California, and covers procurement, deployment, upgrades and support for the company’s MOTH tactical spectrum analyzer. The award was published on the Army contract list on August 27, 2026, and runs through August 27, 2031.

What the MOTH actually does

The MOTH is a passive receiver. It does not transmit and it does not interfere with anything — it listens. Working from published vendor material, it monitors RF activity across roughly 5 MHz to 6 GHz and helps the operator decide whether something abnormal is on the air: the frequency, signal strength, direction and waveform character of each emitter. Drone control links, two-way radios, anything that transmits shows up.

• Coverage: approx. 5 MHz – 6 GHz (vendor-reported)
• Weight and size: 0.99 lb (≈450 g), 5.78 × 3.3 × 1.8 in (vendor-reported)
• Carry: in hand, or strapped to a vest
• Built in: GPS, vibration alerts, a direction-finding mode, real-time spectrum display
• Interop: connects to ATAK, so RF observations land on the tactical map
• Environment: IP67, −10 °C to +55 °C (vendor-reported)

A note on evidence: we have not tested this unit. Every figure above is vendor-reported or taken from the contract announcement, checked September 2026.

Is it just a ruggedized RTL-SDR?

Fair question, and the honest answer is “partly”. Think of the MOTH as what the RTL-SDR ecosystem looks like after it grows up and joins the infantry. Both are wideband receivers that make the invisible spectrum visible. An RTL-SDR dongle is an exploration tool — cheap, ideal for learning radio, fine for scanning broadcast, airband, ham and digital signals. The MOTH packs wideband reception, a real-time spectrum display, signal analysis, direction finding, GPS and a tactical data interface into one sealed unit.

The difference that matters is the last step. The MOTH is built so a non-specialist can read the result quickly: is this band abnormal, where is the emitter, does that waveform look like a drone link. An RTL-SDR gives you a waterfall and expects you to know what to do with it.

Who carries one

Not everybody. The MOTH will not be issued like a personal radio. It is a portable electronic-reconnaissance asset, used to find, identify and locate transmitters — an enemy drone link, a concealed radio. Expect it with scouts, special operations forces, electronic-warfare personnel and squad leaders first, not one per soldier.

The price, and what is in the box

The MOTH is also on the civilian market: Lumenier lists it at $4,950 (checked September 2026). The set includes the analyzer, two batteries, a USB-C charger, a vest-style pouch, a protective case and a pair of antennas — one for the low band, one for the high band.

What this means if you are buying detection equipment

We have not tested the MOTH and this article is contract reporting plus published specifications — nothing more. Still, the purchase confirms a pattern we keep explaining to clients: professional buyers treat RF-spectrum listening and Remote ID reception as two separate layers, and budget for them separately. A spectrum analyzer hears that something is transmitting; a Remote ID receiver tells you who it is. Most sites we advise end up needing both, in that order.

If your concern is…	RID receiver	RF spectrum analyzer
Drones that broadcast Remote ID	Sees them — ID and position	Sees a signal, no identity
FPV, modified or silent aircraft	Blind	Detects the transmission
False alarms	Low	Higher — 2.4/5.8 GHz bands are shared with Wi-Fi
Typical budget	$129–2,500	$3,500–15,000

If the MOTH contract says anything to a non-military buyer, it is this: passive RF listening has moved from a hobby project to standard procurement. The same two-layer logic applies at prison fences, airports and event perimeters — at civilian budgets.

Go deeper: how RF-spectrum detection works, in plain terms → Spectrum detection explained. Shortlist hardware → receiver candidates, with sources and dates. Not sure which layer your site needs? Start with the free screening, answer within one business day.

Content last reviewed: 2026-09-11. Sources: US Army contract announcement (August 27, 2026); Heaviside Industries and Lumenier public product material (vendor-reported).