Mercury specialty positioner

Use 52 lb as the balanced mobile payload limit and 75 lb as the balanced fixed or stationary limit. These figures refer to the total payload carried by the positioner, so sensor housings, brackets and interface hardware should be included in the load calculation. The payload must also be balanced because an allowable centre-of-gravity offset or overturning moment is not defined. The base unit itself weighs 52 lb (23.6 kg) before payload wings, which must be considered when sizing vehicle roofs, masts and support structures. In practice, establish the mounting mode first and then verify total mass, payload balance and structural stiffness.

The positioner provides continuous 360° pan and 180° tilt arranged as ±90°, with both axes operating between 0.005°/s and 100°/s. Position resolution is 0.01°, while repeatability is specified as 0.05°. This range allows the same mechanism to undertake slow observation movements, scanning routines and faster target-to-target repositioning. The continuous pan path incorporates a dual-channel HD-SDI slip ring, avoiding a video-cable restriction on azimuth rotation. Payload clearance should still be checked throughout the full tilt envelope, particularly when wide brackets or multiple sensor housings are fitted.

The required input is 24–28 V DC, with 24 V DC specified as the nominal operating voltage. Current remains below 8.0 A at peak, below 6.0 A during continuous simultaneous pan and tilt movement with payloads, and below 2.1 A in standby. The power source, cable conductors and protection devices should therefore be sized for the peak demand rather than the standby figure. Voltage drop also needs to be assessed where the positioner is installed on a tall mast or connected through a long vehicle cable run. A matching power supply can be requested, but its suitability should be confirmed against the complete payload and cabling arrangement.

The Mercury HD-SDI pan-and-tilt positioner can be controlled through IP or serial RS-232/RS-422 connections, with native PTZ and Pelco-D command support. Serial-over-IP operation and a virtual serial link over a single IP connection allow serial payloads to be incorporated into a networked system. Payload communications include four configurable serial ports, two TTL ports and one IP port, while an embedded web server provides onboard network access. The 10-bit linear velocity response and direct degrees-per-second commands are relevant where host software must generate defined movement profiles. Protocol command coverage, addressing and serial electrical levels should be confirmed during system integration.

Two HD-SDI video channels can pass through the positioner, including across the slip ring used for continuous pan rotation. This arrangement is intended for multi-sensor systems such as dual EO/IR payloads that require more than one video path. Dual GigE pass-through connections are also available for network cameras, encoders or other Ethernet payloads. As GigE is described as an available connection, it should be confirmed as part of the required configuration rather than assumed for every unit. The 53-contact D38999 payload interface and selected base cable must also be checked against the system pin allocation, signal types and required cable length.

The positioner is specified with IP67 protection, MIL-STD-810 salt/fog provisions and an operating range of -32°C to +55°C. These characteristics support use on outdoor surveillance poles, towers, marine platforms and ground vehicles within the stated environmental limits. The complete installation must still account for sealing at external connectors, cable entries and payload interfaces because system-level protection depends on every connected component. Mobile mounting also requires consideration of the 52 lb base-unit mass and the permitted 52 lb balanced payload. Detailed vibration, shock and individual environmental test methods are not defined, so installation-specific qualification may be necessary for demanding platforms.

A stabilised architecture is documented, but stabilisation should be specified explicitly rather than assumed to be standard in every positioner. The configured design uses gyroscopic feedback, a PID control loop, adjustable feedback settings, drift compensation and phase compensation where required. Testing with two balanced 35 lb payloads showed that rejection ratio varied with disturbance frequency and axis; for example, azimuth reached 10.00 at 0.10 Hz, while elevation reached 11.54 at 0.20 Hz. A rejection ratio of 10 means that 7.5° of platform movement would produce approximately 0.75° of line-of-sight movement under comparable conditions. Selection should therefore consider the platform disturbance spectrum, sensor field of view, payload balance and required pointing stability.