What slew rate does a counter-drone pan-tilt positioner need?

Enough to bring the sensor onto a cue from a radar or RF detector within the time budget, then enough low-speed smoothness to track. Published positioners range from about 60 °/s for heavy payloads to 400 °/s for a 15 kg class unit. Specify acceleration too: reaching 400 °/s is only useful if the axis gets there quickly, which sets peak torque and drive current.

Why are backlash-free or direct-drive axes preferred?

Small drones manoeuvre quickly and appear small in the sensor's field of view, so tracking must be smooth and precise at low rates and fast in reversals. Backlash in a gear train causes lost motion at every direction change, and gear compliance lowers the stiffness the tracking loop can use. Direct-drive frameless motors, or preloaded zero-backlash gearing such as strain-wave sets, avoid both.

What does a counter-UAS positioner slip ring carry?

Power for the sensor head and any heaters, control signals, and sensor data, which for HD and thermal video, radar or RF receivers is usually Ethernet. Many heads need continuous pan, so the slip ring is essential. Specify the number of gigabit Ethernet channels, video formats, power per ring and drag torque, and consider a fibre optic rotary joint when data rates outgrow copper.

Can a counter-UAS positioner run from vehicle power?

Yes, if the drive and electronics are designed for the vehicle's power standard. Commercial positioners often run from 24 V DC; on a military ground vehicle the supply follows MIL-STD-1275E (28 V nominal, 20–33 V steady state, with surges and spikes) or DEF STAN 61-5 Part 6. Fast slews draw high peak current, so check the drive's input protection, filtering and any energy storage.

Which encoder suits a fast-slewing sensor head?

An absolute encoder mounted directly on each axis, with high resolution, low noise and a fast serial interface such as BiSS-C. The encoder must also be rated for the maximum axis speed. Moog's direct-drive gimbal stage uses a 26-bit optical absolute encoder, and capacitive and inductive ring encoders offer thin, robust alternatives for hollow-shaft heads.

What should I send for a counter-UAS positioner component enquiry?

Send payload mass, inertia and centre of gravity, pan and tilt ranges, maximum slew rate and acceleration, slow tracking rate and smoothness target, pointing accuracy, slip ring power and data channels, supply voltage and standard, mounting platform (fixed, vehicle, mast, vessel), environment, ingress, shock, vibration and EMC requirements, and production quantity.

Counter-drone pan-tilt positioners and slip rings

Specify Motion technical library · Updated 29 October 2026 · How we prepare our content

In short:Counter-UAS sensor platforms need positioners that slew fast to a cue and then track a small, agile target smoothly, often on a vehicle or mast. That means direct-drive or backlash-free axes, high peak torque, absolute encoders, and slip rings with enough bandwidth for radar, RF and EO/IR sensor data. Specify speed, acceleration and tracking smoothness together, not top speed alone.

Typical requirements

Fast pan-tilt slew rate (example)	0.001–400 °/s, 15 kg payload, 10 Nm, 0.002° accuracy
Heavy positioner (example)	Up to 68 kg balanced at 0.005–60 °/s, 0.05° repeatability
UAV-mounted gimbal slew (example)	200 °/s with continuous pan
Direct-drive gimbal stage encoder (example)	26-bit absolute, 0.01° static pointing accuracy
Positioner supply (examples)	24 V DC; up to 1 kW peak on a fast positioner
Positioner environment (example)	IP67 marine option; MIL-STD-810H Methods 514.8 and 516.8

Machinery we specify motion for

Fast-slewing pan-tilt sensor positioners
Rotating drone-detection radar heads
RF direction-finding heads
EO/IR tracking sensor heads
Mast-mounted sensor heads
Vehicle and vessel-mounted sensor platforms

Counter-UAS systems detect, track and identify small uncrewed aircraft, then hand them to an effector. This page deals only with the motion platforms for the sensors and effector mounts, at component level: the pan-tilt positioners, rotating radar and RF sensor heads, slip rings, encoders and drives. It does not cover how drones are defeated.

The motion requirement is unusual. A typical sequence is a cue from a wide-area radar or RF detector, a fast slew of an EO/IR or narrow-beam sensor onto that bearing, then smooth tracking of a small target that can change direction quickly. The platform may be a fixed tower, a mast, a vehicle or a vessel. So the axes need high acceleration, smooth low-speed tracking, stiffness, continuous rotation and robust data transfer, often all on a 24 or 28 V supply.

Fast-slewing pan-tilt positioners

Published positioners show how wide the envelope is:

Example	Payload	Speed	Accuracy	Notes
DAT-CON PT Spirit	15 kg	0.001–400 °/s pan and tilt	0.002°	10 Nm, 24 V DC, 1 kW maximum, backlash-free, brake, Ethernet
Quickset TAURUS R	Up to 68 kg balanced	0.005–60 °/s	0.05° repeatability	24 V DC, continuous pan via slip ring, IP67 marine option, MIL-STD-810H vibration and shock
Moog AC7332 gimbal stage	1,112 N axial load capacity	Slew-to-cue and slow tracking (no rate published)	0.01° static pointing	Direct-drive 32-pole BLDC, 26-bit encoder, integrated slip ring

Sources: DAT-CON via Unmanned Systems Technology, Quickset TAURUS R datasheet, Moog AC7332 datasheet.

The trade-off is plain in the table: the fastest units carry lighter payloads. When specifying, start from the time allowed to reach a cued bearing, then derive acceleration and peak speed, then check that the payload’s inertia allows it.

Worked sizing example

A sensor head with 0.5 kg·m² of inertia about the pan axis must slew 90° in 0.5 s from rest to rest, using a symmetric accelerate-decelerate profile.

Half the move (45°, 0.785 rad) takes 0.25 s, so acceleration = 2 × 0.785 / 0.25² ≈ 25 rad/s².
Peak speed = 25 × 0.25 ≈ 6.3 rad/s, or about 360 °/s.
Acceleration torque = 0.5 × 25 ≈ 12.5 Nm, before friction, slip ring drag, cable drag, wind and imbalance.
Add margin (a rule of thumb is 30–50% for these unknowns) and you are at roughly 16–19 Nm peak, which points to a direct-drive frameless motor or a stiff, low-ratio, backlash-free gear stage.

Repeat for tilt, where gravity imbalance usually adds a steady torque.

Direct drives, gearing and motors

For the fastest and smoothest axes, direct-drive frameless torque motors remove backlash and keep stiffness high; Moog’s AC7332 uses a direct-drive 32-pole brushless motor. Where payloads are heavy and torque would make a direct drive too large, use preloaded zero-backlash gearing such as strain-wave sets; see harmonic vs planetary vs cycloidal and frameless motor sizing. Low-cogging motors help slow tracking, and a holding brake keeps the head parked for transport.

Radar, RF and EO/IR sensor heads

Rotating surveillance radars for drone detection use the same building blocks as larger radars: continuous azimuth rotation, an integrated slip ring, RF or fibre optic rotary joint and encoder. SPINNER notes that fibre optic rotary joints reach several Gbit/s and can be combined with slip rings and RF joints. Our radar pedestal page covers the joint stack. RF direction-finding heads and EO/IR turrets on the same mast often share a positioner, which drives up slip ring channel count. For EO/IR head design see the EO/IR gimbal page.

Slip rings for counter-UAS heads

Continuous pan is normal, so every head needs a slip ring carrying power, control and sensor data. For a gimbal mounted on a UAV or small head, low-torque miniature capsules such as Moog’s miniature gold capsules suit low-power circuits; for HD and thermal video plus Ethernet, use Ethernet slip rings or the higher-bandwidth EO/IR slip rings, which Moog rates at up to about two dozen channels over 400 Mbit/s each. Add a fibre optic rotary joint when copper runs out of bandwidth. Read Ethernet through slip rings and CCTV and pan-tilt slip rings.

Encoders and drives

Absolute encoders on each axis give position at power-up and support pointing to a cued bearing. They must handle the axis’s top speed and the platform’s shock and vibration; Netzer’s VLP, for instance, is rated to 100 g for 6 ms and 20–2,000 Hz vibration. See absolute vs incremental encoders.

The servo drive needs enough peak current for the acceleration above, a fast current loop for smooth tracking, and a network interface the system controller can command at high update rate. A motion controller or the sensor system computer closes the tracking loop.

Fixed, mast, vehicle and vessel mounting

The mounting platform changes the specification. A fixed tower gives a stable base, so the axes only need to follow the target. A telescopic mast adds sway in wind, and a vehicle or vessel adds pitch, roll and vibration that the axes must reject, which pushes the design towards the stabilised-gimbal approach: gyro feedback, stiffer structure and more continuous torque. Mobile heads also see transport shock and must park and lock for movement. State the mounting case up front, because it can double the torque and bandwidth required.

Environment, power and EMC

Power. Positioners often run from 24 V DC; on military vehicles, design for MIL-STD-1275E or DEF STAN 61-5 Part 6. Fast slews draw high peak current.
Environment. Outdoor heads need IP67-class sealing, wide temperature ratings, and vibration and shock testing to the tailored MIL-STD-810H profile; Quickset’s example cites Methods 514.8 and 516.8.
EMC. Counter-UAS sites combine radar, RF receivers and jammers next to motor drives. Drive emissions can desensitise RF detectors, so MIL-STD-461 or DEF STAN 59-411 limits and good shielding are essential.
Export control. Counter-UAS equipment and its specially designed components are likely to be controlled; see the defence and security overview.

Typical pitfalls

Specifying maximum slew rate without acceleration.
Choosing geared axes with backlash for a tracking task.
Running out of slip ring bandwidth when a sensor is added.
Ignoring drive emissions next to RF detectors.
Forgetting tilt imbalance when payloads are changed in service.

Send your payloads, slew and tracking targets and data channels, and our engineers can propose positioner motors, slip rings, encoders and drives.

Direct-drive motors for fast pan-tilt positioners

A counter-UAS sensor head must slew quickly to a cued bearing, then track smoothly at low rates and reverse without lost motion, which is why direct-drive frameless motors suit the fastest heads. Size from the move: the worked example on this page reaches about 25 rad/s² and 12.5 Nm for a 0.5 kg·m² head moving 90° in 0.5 s, before friction, drag, wind and imbalance. Check continuous torque for tracking and wind on a mast or vehicle, cogging and ripple for slow tracking, and stiffness against the loop bandwidth. Specify bore for the slip ring, envelope, bus voltage and a holding brake for transport.

Fast pan-tilt positioners: direct-drive pan and tilt
EO/IR tracking heads: low-cogging smooth axes
Rotating radar heads: direct-drive azimuth
Vehicle-mounted heads: stiff, backlash-free axes