Police Thermal Drones: How Departments Use the DJI Matrice 4T

A police thermal drone earns its keep when officers on the ground can't see enough: a missing hiker after dark, a suspect who ran into a field, a crash blocking a highway. Here's how departments use a thermal drone like the DJI Matrice 4T on those calls, what the camera can and can't do, and the FAA paths for starting a program.

What the thermal camera actually shows you

The Matrice 4T's thermal camera is a 640 × 512 uncooled VOx sensor (vanadium oxide, a common sensor material in thermal cameras that don't need cooling), with a Super Resolution mode that outputs 1280 × 1024. It's radiometric (every pixel stores a temperature reading, not just a color), so you can spot-check temperatures later from R-JPEG files (DJI's radiometric photo format). DJI lists accuracy at ±2°C or ±2%, whichever is greater, in high gain mode (the setting for -4°F to 302°F scenes).

What it won't do matters just as much:

It reads surface heat. It doesn't see through walls, and glass blocks the 8 to 14 μm wavelength the camera works in, so a person behind a window may not show up.
Contrast changes through the night. Pavement and rock that soaked up sun all day stay warm after sunset. A person stands out best once the ground cools, often late night and early morning.
Thick canopy hides people. Thermal works best in open ground, brush and broken tree cover.

Search and rescue

DJI's own search and rescue workflow for the Matrice 4T is a good baseline:

Launch near the last known point and fly a search pattern such as a spiral.
Use White Hot or Black Hot palettes (the color schemes that show heat as white or black). They're the easiest to read on a small screen.
When you find a hot spot, zoom the thermal and visual cameras together (DJI calls it Link Zoom) to confirm it's a person and not a deer or a warm rock.
Mark the location and get it to ground teams. The laser rangefinder (rated to 1,800 m on a 20% reflectivity target) helps put a position on what you're looking at.
Use the AS1 speaker to talk to the person and the AL1 spotlight to light the path for the ground team.

Give the incident commander a livestream so the pilot can focus on flying. DJI rates max flight time at 49 minutes without wind or accessories, so plan on less and rotate batteries. The aircraft operates from 14°F to 104°F, and its batteries don't support low-temperature charging, so keep spares warm in the cab in winter.

Suspect tracking and perimeter overwatch

For a foot pursuit or a barricaded subject, the drone gives the perimeter team eyes they can't get from the ground. The Matrice 4T's telephoto camera is a 168 mm equivalent lens with up to 112x hybrid zoom, which lets the pilot hold position off to the side instead of hovering right overhead. In low light, its night scene mode and NIR auxiliary light (a near-infrared illuminator for night images) help the visual camera, and the thermal camera does the rest.

Stand off so the drone's noise doesn't give it away, call out movement on the radio by direction and landmark, and record the flight. Footage often ends up in reports and court.

Surveillance flights also raise privacy and Fourth Amendment questions. Your department needs a written policy covering when you fly, who approves it, and how long you keep footage. For a model, the Department of Justice's own UAS (unmanned aircraft system, meaning the drone and its control equipment) policy for its federal components requires approvals, training, privacy reviews, and generally limits keeping data with personal information to 180 days unless there's an authorized reason. State laws on police drone use vary, so have your legal counsel review your policy.

Accident reconstruction

Drones cut the time a crash keeps a road closed: fly a mapping mission and software stitches the photos into a measurable 2D map or 3D model. An honest note: for crash mapping, DJI's recommended tool is the Matrice 4E, not the 4T. The 4E has a 20 MP 4/3-inch camera with a mechanical shutter (it avoids the warping a rolling electronic shutter causes on moving shots), which is better for photogrammetry (measuring from photos). DJI pairs it with DJI Terra for processing and DJI Modify for cleaning up 3D models. The 4T still documents a scene well with overview photos and video. If reconstruction is a big part of the job, plan on a 4E for it and a 4T for thermal calls. For night scenes, DJI says to light the scene properly before you fly the mapping mission.

DFR programs (drone as first responder)

DFR means launching a drone to a 911 call so it arrives before, or with, the first patrol car. The FAA is blunt that "DFR is a concept, not a special set of flight regulations." Flying to a call a mile away usually means BVLOS (beyond visual line of sight, flying farther than the pilot can see the drone), which the standard rules don't allow without a waiver.

The FAA currently offers two main routes:

Part 91.113 waiver for public agencies. For agencies that are both a PAO (public aircraft operator, a government agency flying for government purposes) and a PSO (public safety organization). It allows VLOS (visual line of sight) and BVLOS flight, night operations, and flights over people and moving vehicles with mitigations. It's valid 48 months. Without an approved detect-and-avoid system (equipment that electronically spots other aircraft), BVLOS flights rely on obstruction shielding (staying low near buildings and trees, where manned aircraft don't fly), ADS-B In (a receiver that shows nearby manned aircraft), and an anti-collision light, and are typically limited to 200 feet above the ground or staying close to obstructions. The FAA's FAQ says this waiver replaced the older Tactical BVLOS and First Responder BVLOS COAs (certificates of waiver or authorization, the FAA's approvals for public agencies) for new applicants.
Part 107 PSO Shielded Operations waiver. This one falls under Part 107 (the FAA's standard commercial drone rules) and is for public safety groups that don't qualify as public aircraft, such as volunteer fire departments and search and rescue teams. It covers BVLOS, flights over people and over moving vehicles during emergency callouts. It doesn't cover controlled airspace, so you need a separate airspace authorization near airports.

Dock-based DFR (a drone that launches itself from a rooftop box) uses dock aircraft like the Matrice 4TD (it pairs with DJI Dock 3) rather than the 4T, which is a hand-launched, patrol-car drone.

COA basics: Part 107 or public aircraft

Per the FAA, a government agency has two ways to fly drones under 55 lb:

Part 107. Each pilot holds a remote pilot certificate and drones are registered. Flights stay at or below 400 feet and within visual line of sight. Night flying is allowed if the pilot trained under the current rules (after April 6, 2021) and the drone has anti-collision lighting visible for 3 statute miles. You still need airspace authorization near airports. Pilots must also stay current with recurrent training every 24 months.
Public aircraft COA. The agency certifies its own pilots and drones for government work. Your legal department writes a public declaration letter, and you apply online. The FAA says it usually responds within 60 days of a complete application. The basic blanket COA is VLOS-only and requires NOTAMs (notices that alert other pilots to your flights) and monthly reporting.

For an emergency that doesn't fit your approvals, the FAA's SGI process (Special Governmental Interest, fast-track emergency approval) can add authority quickly. For time-sensitive requests, the FAA lists 202-267-8276.

Starting a program: what we'd do first

Pick your legal path (Part 107, COA, or both) with your city or county attorney.
Write the policy before the first flight: mission types, approvals, data retention, records requests.
Train on reading thermal, not just flying. Practice on known targets in daylight and at night.
Kit for the real call: at least three batteries, the AL1 spotlight, the AS1 speaker, and a charging setup in the vehicle.
Check purchasing rules. Some states and grant programs limit which drone brands agencies can buy. Check before you budget. Our post on whether DJI drones are banned covers the federal side.

Equipping your team

You can configure the DJI Matrice 4T with extra batteries, the spotlight and the speaker, the same pieces as our Matrice 4T Law Enforcement Kit. You can also browse our law enforcement and search and rescue gear. If you want to talk through a setup for your department, call us at 1-877-992-8279 or email sales@avarydrone.com.

This article is general information, not legal advice. FAA waiver processes change often, so check current FAA guidance and your agency's legal counsel before you fly.

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How Police Departments Use Thermal Drones (Matrice 4T in the Field)