EO/IR surveillance turrets
for persistent watch.

01 Engineering brief

Begin with the sector, not the lens

An EO/IR surveillance turret is part of a site, not a standalone camera. The first design question is which airspace or ground sector must be covered, at what revisit rate, and from which elevation. A continuous 360° requirement produces a different pedestal, slip-ring and control architecture from a sector scan that sweeps backwards and forwards. The second question is what the operator must be able to decide at the end of the optical chain: detect movement, recognise a vehicle type, identify a person or measure a target location.

These questions determine whether a 60× visible zoom and a 75 mm thermal channel are enough, or whether the site needs multiple turrets with overlapping coverage. A single long-range sensor cannot simultaneously provide high revisit rate over a wide sector and a narrow, stable image at maximum zoom. The honest design process accepts that trade and allocates sensors accordingly.

03 Engineering brief

Calculate usable recognition distance

Published detection ranges are usually based on a target of a stated size, a defined contrast and a clear atmosphere. Recognition and identification require more pixels on target and therefore shorter usable distances. The calculation should start with the sensor's angular resolution, the target dimension and the number of pixels needed for the task. Then apply an allowance for atmospheric attenuation, platform vibration and display quality.

For visible imaging, zoom is not the same as resolution. A 60× zoom lens on a 1440-line sensor may produce a highly magnified but soft image if the optics, focus and atmospheric path cannot support the magnification. For thermal imaging, the 75 mm lens and detector pitch determine the instantaneous field of view; a larger detector or a longer lens can improve pixel coverage but narrows the search field. Always ask for a matched image at the claimed distance, not only a range table.

Target location adds a laser rangefinder and a boresight requirement. The rangefinder's beam divergence, update rate and minimum range must match the target geometry. A 5 km range figure is not useful if the beam is too wide to isolate a small object or if the range is not aligned with the imaging channel. Check the boresight procedure and the stability of alignment after transport.

05 Engineering brief

Acceptance and commissioning

Commissioning should begin with a mechanical and electrical check before the turret is pointed at a live scene. Verify the mount torque, cable clearance, supply voltage and network path. Then run a slow 360° sweep and a series of commanded moves through the full elevation range. Record settling time, overshoot and any cable or housing interference.

Next, perform an optical alignment check at wide and narrow zoom. Confirm that the visible and thermal channels remain boresighted across the zoom range and that the laser rangefinder agrees with a known distance. Capture reference frames at several zoom settings and ambient conditions. Finally, test the operator workflow: can the control room find, identify and hand off a target without losing the track? The technical acceptance criteria and the operational workflow should be signed off together.

Keep a commissioning record that includes firmware versions, network settings, alignment results and baseline images. This becomes the reference for future maintenance and for comparing a second site. The engineering team can review the site plan, power and data requirements before a quotation is finalized.