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BATTLESPACE visited Atlantic Inertial Systems in Plymouth
History of AIS
It is worth looking at the history of the UK arm of AIS before we look at the technology.
AIS started its life as a subsidiary of Sperry Corporation of the USA. The company was founded in 1910 as the Sperry Gyroscope Company by Elmer Ambrose Sperry to manufacture navigation equipment, chiefly his own inventions – the marine gyrostabilizer and the gyrocompass at 40 Flatbush Avenue Extension in Downtown Brooklyn.[1] During World War I the company diversified into aircraft components including bomb sights and fire control systems. In their early decades, Sperry Gyroscope and related companies were concentrated on Long Island, New York, especially in Nassau County. Over the years, it diversified to other locations.
British Sperry operations began in 1913 at a small factory in Pimlico, London. The first customer was the Admiralty, and HM Submarine E.l was the first of many British warships to have a marine gyro compass. Adoption of this aid by the merchant service followed the Great War, the first British ship so fitted being RMS Aquitania in 1919. In 1915 Sperry in Britain became the Sperry Gyroscope Co Ltd, with head offices in Victoria Street, London. Two years later, to meet increasing demand, production facilities were transferred to larger premises at Shepherds Bush. The development of flight instruments and automatic flight control proceeded concurrently with the marine applications.
Plymouth was set up in 1975 (or mid 70’s), the premises were acquired from the then Remington Rand.
Sperry then sold their Gyroscope Division to BAE in 1982.
Atlantic Inertial Systems, previously BASE was created following its divestiture from BAE Systems to J.F. Lehman & Co, a US investment company, in August 2007. AIS has facilities in Cheshire CT, Heath, OH and Totowa NJ, in the USA, and in Plymouth, UK and employs over 800 personnel worldwide providing a range of Inertial Sensors, Inertial Measurement Units & Inertial Navigation Systems for guidance, control and navigation of platforms, systems and weapons in worldwide aerospace and defence markets. The company also provides TERPROM® the world's most advanced digital terrain system which provides terrain referenced navigation, predictive ground proximity warning and weapon aiming capabilities.
On November 17th 2009 Goodrich Corporation signed an agreement with an investment affiliate of J.F. Lehman & Company to acquire AIS Global Holdings LLC (AIS). Sales in 2009 for the business were approximately $180 million, and are expected to grow significantly over the next several years. The purchase price was approximately $375 million.
AIS employs approximately 800 people at facilities located in Cheshire, Conn; Heath, Ohio; Plymouth, UK; and Totowa, N.J. Major customers include defense prime contractors as well as U.S. and allied military forces around the world. Primary products include inertial sensors, inertial measurement units (IMUs), integrated IMU/GPS systems, stability systems, and terrain avoidance systems for missiles, military aircraft and land systems. AIS will become part of Goodrich's Sensors and Integrated Systems business, within its Electronic Systems segment.
AIS is a leading supplier of mission critical hardware to 250 programs in 28 countries and has a proud heritage stretching back over 90 years through BAE Systems, Plessey, Allied Signal, Kearfott and Sperry.
AIS has extensive capabilities including:
* Systems Design
* Kalman Filter Design
* High Volume Production of Inertial Sensors and Systems
* Systems Test
* MEMS Sensor Design and Fabrication
* Mission Simulation
In this article, we will concentrate on the production of inertial sensors and systems
Inertial Sensors and Sensor Systems
Before we describe the products being produced by AIS, we should look at the development of the gyroscope. Gyroscopes appear in practically every form of item used throughout the world from planes, trains and cars thru missiles and rockets, even to model helicopters. Without them all of the above would not work, they are the unsung heroes of motion technology.
A gyroscope is a device for measuring or maintaining orientation, based on the principles of conservation of angular momentum. A mechanical gyroscope is essentially a spinning wheel or disk whose axle is free to take any orientation. This orientation changes much less in response to a given external torque than it would without the large angular momentum associated with the gyroscope's high rate of spin. Since external torque is minimized by mounting the device in gimbals, its orientation remains nearly fixed, regardless of any motion of the platform on which it is mounted. Solid state devices also exist, such as the ring laser gyroscope.
Applications of gyroscopes include navigation (INS) when magnetic compasses do not work (as in the Hubble telescope) or are not precise enough (as in ICBMs) or for the stabilization of flying vehicles like Radio-controlled helicopters or UAVs. Due to higher precision, gyroscopes are also used to maintain direction in tunnel mining.
Within mechanical systems or devices, a conventional gyroscope is a mechanism comprising a rotor journaled to spin about one axis, the journals of the rotor being mounted in an inner gimbal or ring, the inner gimbal being journaled for oscillation in an outer gimbal which in turn is journaled for oscillation relative to a support. The outer gimbal or ring is mounted so as to pivot about an axis in its own plane determined by the support. The outer gimbal possesses one degree of rotational freedom and its axis possesses none. The inner gimbal is mounted in the outer gimbal so as to pivot about an axis in its own plane that is always perpendicular to the pivotal axis of the outer gimbal.
The axle of the spinning wheel defines the spin axis. The inner gimbal possesses two degrees of rotational freedom and its axis possesses one. The rotor is journaled to spin about an axis which is always perpendicular to the axis of the inner gimbal. So, the rotor possesses three degrees of rotational freedom and its axis possesses two. The wheel responds to a force applied about the input axis by a reaction force about the output axis.
The behaviour of a gyroscope can be most easily appreciated by consideration of the front wheel of a bicycle. If the wheel is leaned away from the vertical so that the top of the wheel moves to the left, the forward rim of the wheel also turns to the left. In other words, rotation on one axis of the turning wheel produces rotation of the third axis.
A gyroscope flywheel will roll or resist about the output axis depending upon whether the output gimbals are of a free- or fixed- configuration. Examples of some free-output-gimbal devices would be the attitude reference gyroscopes used to sense or measure the pitch, roll and yaw attitude angles in a spacecraft or aircraft.
It is not only that the AIS gyro technology has no moving parts, it is the size, weight and complexity of these systems which is fantastic.
Dr Geoff Henderson, Technical Director and Chief Scientist at AIS showed the Editor the latest MIMIM IMU which is 1 cubic inch.
“If you go back thirty years, the same system would be about 6 inches long and 4 inches in diameter, such as the one made for the conventional Seawolf Missile.” He said
“The biggest development in gyro manufacture came about in the 1980s when oscillating coriolis forces, rather than spinning wheels, were used in manufacture and thus eliminating all moving parts. In the early days these Coriolis gyros were made out of ceramic or metal but in the late 1990s they began to be made in silicon and this makes miniaturisation possible. It is through the work we have carried out with our Joint Venture partners Sumitomo that we can use their silicon manufacturing technology and miniaturization techniques to make such small assemblies. Virtually every car made around the world has a miniature gyro to monitor its braking system. Sumitomo supply as many as 2 or 3 million units a year. At AIS, we use the same technology, ruggedise it and use it for military and aerospace applications. The fact that the system is buried within the systems of either a missile or an aircraft requires a very comprehensive testing regime as each gyro will have to operate for years without servicing. In addition, we do a lot of shock, vibration and ballistic testing to ensure that our systems withstand the missile, rocket and gun launch.”
AIS is a market leader in inertial sensors and sensor systems, both traditional spinning wheel gyros and solid state MEMS sensors. Over 20,000 AIS MEMS IMU's, including gun hard variants, are in use today on platforms such as RAM, Seawolf, APKWS, NLAW and Excalibur; and more than 5 million spinning wheel based products have been delivered worldwide to a huge range of customers and applications.
To date, AIS has delivered over 4 million instruments and has more than 20,000 MEMS sensors in service with its military and aerospace worldwide customer base. TERPROM® is in service on over 5000 aircraft.
Excalibur Inertial Measurement Unit
In 2008, Atlantic Inertial Systems (AIS) was selected to supply the Excalibur Inertial Measurement Unit (IMU) following excellent performance on the Raytheon-led ERGM U.S. Navy course-corrected projectile project, since cancelled. AIS recently delivered the 1000th SiIMU02® and entered high rate production for Excalibur. This unit was part of the first high rate production batch of 200 per month for Raytheon Missile Systems (RMS) Excalibur precision guided missile system from a total requirement for 2000 a year. The AIS SiIMU02® replaces the Honeywell system originally chosen for the requirement, but dropped due to technical problems. The SiIMU02® is in service on a range of programmes including the A Darter,(Air-Air Missile), APKWS - 70mm (2.75 inch) Guided Rocket, and Roketsan,2.75 inch Guided Rocket. It is also currently under consideration for a number of international programmes.
Alison Fenn, Business Development Director of AIS told BATTLESPACE, “This is a fantastic milestone for AIS. We achieved the first 1000 SiIMU02® units delivered and we have proven our high rate manufacturing capacity - which is essential as we move forward on the Excalibur programme.”
Excalibur 1a tests using the AIS IMU began 16 months ago and have demonstrated one hundred percent reliability and unprecedented accuracy. In a recent announcement, RMS described firing two precision-guided projectiles from a Paladin gun system during the first guided flight test of the Raytheon Excalibur 1b program and stated that these firings demonstrated accuracy better than required. AIS supplied the IMU for these successful tests, which maintained the Company's enviable success record in guided gun firings. In September'08 AIS was awarded a Supplier Excellence award by Raytheon Missile Systems in recognition of its exceptional performance throughout the previous year supplying SiARS® to the Rolling Airframe Missile (RAM) programme.
In September 2009, AIS delivered its 1000th SiIMU02® unit. This unit was part of the first high rate production batch (200 per month) for Raytheon Missile Systems(RMS) Excalibur precision guided missile system. The SiIMU02® is in service on a range of programmes including the A Darter, (Air-Air Missile), APKWS - 70mm (2.75 inch) Guided Rocket, and Roketsan, 2.75 inch Guided Rocket. It is also currently under consideration for a number of international programmes.
New Miniature Silicon Inertial Measurement Unit (IMU)
AIS launched its new miniature silicon Inertial Measurement Unit (IMU) known as MinIM™ at DSEi in 2009. This ruggedized IMU is one cubic inch in size, which is 1/4 the size and weight of the Company's established production MEMS IMUs. MinIM™ uses the latest capacitive rather than traditional inductive technology, keeping production costs low and this size and cost combination is opening up a whole range of entirely new markets to the benefits of reliable, rugged navigation and guidance.
Ian Scaysbrook, Chief Engineer, Atlantic Inertial Systems, told BATTLESPACE, “We believe this new development from our engineering team answers some pressing needs in the defence market, and in other sectors, and will change the face of navigation and guidance systems in the coming years. As the nature of operations has changed and military requirements have evolved, there has been an increasing demand for operational accuracy and for reductions in collateral damage. This very small, lightweight and low cost IMU will make rugged and reliable navigation and guidance possible for a huge range of potential applications - platforms that in many instances have not been able to access existing IMU technology. We are also working with Team Complex Weapons (TCW) in the U.K. to supply IMUs for the Loitering Munition programme and other course corrected applications.”
Among the range of potential applications, MinIM™ will meet the growing demand for navigation of ever smaller guided munitions and projectiles. It will also provide a solution to the need for effective control of smaller unmanned aircraft and air launched systems. And one patented innovation being explored is the installation of MinIM™ inside a soldier's boot to offer navigation and tracking for individual troops during operations.
“What size do you think you could achieve for an IMU?” The Editor asked Geoff Henderson
“We reckon that given sufficient funding that we could make an IMU of 1 cubic centimetre. That would be suitable for the applications we have been discussing such as the guided .50 calibre system.”
“Given the spread of GPS, do you find that there is less demand for your products?”
“Quite the opposite, every military event requires precision and GPS does not always do that, particularly in jungle conditions. We work with GPS manufacturers but do not want our users to become GPS-dependant, given that a loss of GPS connectivity could result in fratricide or blue-on-blue. The success of the Excalibur round means that 155mm canons can now provide missile–like accuracy. We expect this technology to be used for 105mm and other weapons in the future. We are now developing an ‘in the boot’ navigation system for soldiers which will give them exact and precise details of their position. This will be particularly useful in urban combat situations.”
Advanced Production Facilities
The Editor was taken round the spotless production facilities by Carl Harris.
“How many units do you produce here?”
“Depending on the product type, our total production is 8000 units of varying types a month. We do not manufacture any parts here, they are bought in from other suppliers.” Harris said.
“How much testing is required for each unit?”
“Our testing procedure forms the most rigorous part of the manufacturing process. We recently installed new machines to achieve the best results. We estimate that we have an 85% success rate in passing these tests with only a 3% scrappage rate. Most of the systems will be subjected to a rigorous heat and vibration test lasting, in some cases, as long as 40 hours.”
“How many items do you get back here for repair?”
“It varies given the conditions, but we have a dedicated repair and overhaul facility here that is servicing products that go back over decades and we have products designed for 20+ years of military service that are still out there”
Before the Editor left the facility he was given a trial hands-on demonstration on the AIS TERPROM® navigation system which will be the title of a future article.
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