SPS-500

SPS-500 Precision Positioners

Cost-Effective, High-Performance Positioning Systems

All positioners manufactured by Cobham are based upon a scaleable design that is the result of more than 20 years of experience in positioner design, development, manufacture and support. By combining direct-drive, brushless motors, high-accuracy resolvers and digital-servo technology, with a lightweight modular design that can be easily adapted to different payloads, Atlantic's Positioners are the most advanced, reliable and cost-effective precision-positioning systems available.

Cobham Sensor Systems are ideally suited to airborne, shipboard, vehicle-mounted or land-based applications such as surveillance, laser/mmwave communications, tracking, and fire control. They can be Line-Of-Sight (LOS) or space stabilized by the addition of a video tracker or gyroscopes, and drift-control software. GPS is also available for mobile applications.

The SPS-500 Series was designed to fill the gap between low-cost, inaccurate, pan-and-tilt devices and custom-designed positioners. The SPS-500 Series provides a portable, rugged and reliable means of accurately positioning payloads, such as CCD cameras, IR devices, antennas and lasers, weighing up to 60lb, to an accuracy of ±0.0014 degrees (±25 µradians).

The SPS-500 Series Precision Positioning Systems are standard, commercial-off-the-shelf (COTS) items, employing a modular design that allows inexpensive customization to accommodate virtually all payloads. This makes these systems an ideal choice for applications where high precision, low weight, reasonable cost and adaptability are critical.

 Features

1. Cost-effective solution for precise positioning of payloads weighing up to 60lb.
2. Easily adapted to T-bar, yoke or 3-axis configurations.
3. User-friendly firmware provides easy set-up and optimization when payloads are changed.
4. Brushless motors reduce maintenance and EMI.
5. Direct-drive eliminates need for gearboxes, providing zero backlash, and high reliability.
6. Positional resolution up to ±0.0014 degrees (±25 µradians).
7. High-speed microprocessor control and C-based firmware for fast response, ease of use, and flexibility.
8. Can be controlled by either analog or digital signals via an IBM-compatible PC and/or a System Digital Control Unit (SDC).
9. Suitable for hostile environments and high reliability applications.

Superior Adaptability

Traditionally, whenever a payload was changed, regardless of the positioning device, significant and expensive positioner re-design was required. Cobham's Positioners solve this problem by employing a modular design. This philosophy allows the same pedestal base to be re-configured to provide T-Bar, Yoke, and 3-axis configurations. Each of these configurations is also available as a rotator or with an offset elevation-axis.

In addition, the SPS-500 Series employs state-of-the-art firmware and digital control to allow the positioner's performance to be optimized to different payloads, again without costly re-design.

This built-in adaptability greatly reduces any non-recurring engineering costs and reduces time to delivery. These features provide system-integrators with a competitive advantage and make the SPS-500 Series Precision Positioners the ideal choice for applications where payloads are frequently changed or reconfigured.

Precise Positioning

One of the most outstanding features of The SPS-500 Series is positioning accuracy. Payloads can be rapidly positioned to better than ±0.0014 degrees (±25mradians). This high accuracy is achieved by use of optional multi-speed resolvers that provide unmatched positional resolution and rugged noise-immune operation. For less demanding applications, lower-cost, lower-performance resolvers are available.

The low-torque-ripple motors and the inherently stiff mechanical design provide superior stability, making the pedestal ideally suited for positioning long focal-length imaging sensors.

The Positioner's Servo Amplifier Unit can provide automatic error cancellation. This is done by measuring the positional error throughout the pedestal's rotation (once-around-error) and introducing a correction signal during operation.

These features ensure that payloads will always be accurately positioned.

High Reliability

Positioners are typically located in remote, difficult-to-access locations such as building roofs, towers, ship masts, etc. Consequently, Cobham's positioners are designed to minimize the need for maintenance.

The brushless, direct-drive motors used by Cobham's positioners eliminate the problems of brush monitoring and replacement required with traditional motors. They also eliminate arc noise, the need for a gearbox, and gearbox backlash.

The Positioner incorporates various protective measures that greatly reduce the likelihood of damage to the drive motors under conditions of overtemperature, short-ciSDCit, overvoltage, and overspeed.

All Positioning Systems manufactured by Cobham are designed for a long Mean-Time-Between-Failure (MTBF), and a short Mean-Time-To-Repair (MTTR).

All SPS-500 Series Precision Positioners are environmentally qualified for any shipboard or land-based application.

High Payload, Low Weight

The Pedestal itself weighs only 35 lb. but the yoke configuration is capable of rapidly and accurately positioning payloads of up to 60 lb. The low weight makes the SPS-500 Series portable, an enormous advantage for equipment that is typically installed in the most inaccessible locations or needs to be hand carried between locations.

The combination of high payload-to-weight ratio and small size makes the SPS-500 Series ideal for applications where space and weight are limited, and the installation site is difficult to access.

Low Maintenance

In the unlikely event that a problem should occur, the SPS-500 Series Positioning Systems are designed to make diagnosing and correction of failures as simple as possible. Most problems will be detected by the built-in diagnostics, which can detect faults down to the Field-Replaceable Unit (FRU) level. As a result, the MTTR for the system is very low, with training and logistics support simple and low in cost.

Cost effective

The SPS-500 Series Precision Positioners are commercial-off-the-shelf (COTS) items, built to meet the needs of military environments. They combine an excellent performance with a useful life in excess of twenty years, during which minimal maintenance will be required. Because of their high MTBF and low MTTR, down-time will be minimal, a crucial factor for mission-critical applications.

The short lead time and high performance, together with the low cost of acquisition and maintenance, make the SPS-500 Series Precision Positioners the ideal choice where price, performance and time are critical. The modularity assures that NRE costs associated with the product are minimal.

Integrated Solutions

Cobham has extensive experience in the areas of control systems engineering, remote sensing, imaging, laser systems, signal processing, software development, and systems integration. In addition, Atlantic has developed a range of products for use in these areas. These capabilities and products make Atlantic the ideal choice for the provision of turnkey systems, or integration into customer-provided environments.

Stabilized Payload

All Cobham's Positioners are available with optional high-performance stabilization against base motion. Such stabilization can be achieved by using video trackers, accelerometers, tilt-sensors or gyroscopes, depending on the level of stabilization required. With Fiber-Optic Gyroscopes (FOGs), the payload's line-of-sight can be stabilized to better than 100 mradians (RMS). Optional firmware for drift control provides ease of long-term operation. However, it should be noted that achieving a high degree of stabilization depends critically on factors such as payload and platform stiffness, and not just the positioner's capabilities. Atlantic can provide guidance on these design requirements.

Adaptable Control Configuration

The SPS-500 Series Precision Positioning Systems, consisting of a Pedestal and a Servo Amplifier Unit, offer unparalleled control flexibility. The pedestal can be controlled by:

1. Cobham's own System Digital Control Units (SDC)
2. An IBM compatible PC or host computer.
3. A joystick and video monitor.
4. An autotracker.
5. Custom-built control systems.

Optional control functions such as stabilization, drift control, error correction, coordinate conversion, scan modes, test programs, etc. can also be incorporated.

Servo Amplifier Unit

The Servo Amplifier Unit (SAU) is a microprocessor-based, servo controller, providing both position and rate-loop control of the positioner. A firmware download that modifies digital compensation filters allows the servo-loop to be optimized for different payloads.

The SAU includes multiple RS-422/RS232 and parallel ports to allow control of, and access to, the signals generated by sensors and monitoring equipment associated with the payload. Use of brushless, low-torque-ripple motors with Pulse-Width-Modulated (PWM) amplifiers provide rapid and precise control.

The SAU monitors servo faults and provides a number of safety features, which include the ability to prevent remote operation of the positioner while maintenance personnel are working on the unit.

The SAU operates from :

1. 115 VAC, single-phase, 50/60 Hz power.
2. 220/240 VAC, 50/60 Hz power.
3. 24 VDC (optional)

The SAU is available for mounting in a 19 inch EIA rack, in a NEMA weatherproof enclosure or it can be custom packaged.

The SAU can be commanded by an external computer system or joystick.

Direct PC or Host-Computer Control

Cobham Sensor Systems Largo, can also be controlled by connecting a PC or Host computer to the SAU. The control software can be written by the user or supplied by Atlantic. Various interfaces are available, including the UK/MOD SISS standard RS422/RS232, Ethernet and other common COM formats.

The extra processing power available in a PC or host computer offers the following advantages:

1. The status of positioner and its payload sensors can be continually monitored.
2. Images can be continuously displayed and processed.
3. Data from sensors can be processed.
4. Project-specific, test and setup programs can be down-loaded via parallel or RS422/232 protocol.

Autotracker Control

In addition to the above options, the positioner can be controlled automatically by a videotracker, using a joystick and monitor for initial target acquisition, without the need for an SDC, PC or host computer.

System Digital Control Unit

A System Digital Control Unit is available in both Basic and Full-Function configurations.

The Basic SDC is a low-cost option that allows the Positioner to be controlled manually by context-sensitive switches and/or a joystick. It allows for the integration of IRIG timing data, GPS data, and video annotation, as well as providing additional functions such as error correction, coordinate conversion, scan modes, test programs, etc. Additional functionality can be added to further enhance the performance of the system.

In addition to the above features, the Full-Function SDC has an interactive, electroluminescent, touch-screen display. This display, which is the most appropriate for out-of-doors field work, offers greater flexibility and functionality, while allowing more information to be viewed at once.

Both Basic and Full-Function SDCs provide menu-driven instructions that allow users to quickly setup and optimize the servo response of the system to match different payloads, without the need for costly support.

Both versions of the SDC also allow the Positioner to be controlled by a PC or other host computer, facilitating control of multiple positioners and integration of IRIG data and sensor positional data. Additionally, both remote and centralized testing and operation of the positioner can be accommodated.

Both versions of the SDC are available for mounting in a 19 inch EIA rack and can use the same power sources as the SAU.

Summary Performance Specifications

Coatings and Fittings

The pedestal is pre-treat primed and can be marine powder-coat painted, or painted according to customer specifications. It is supplied with stow locks for safe transportation, a pedestal-safe switch allowing maintenance personnel to immobilize the pedestal during maintenance, mechanical end-stops and a payload-specific electrical interface.

Configuration

Mechanical

Environmental

Options

Mechanical Data (not to scale)

All measurements in inches.

Due to Atlantic's on-going product development program, all specifications are subject to change without notice.

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