Queen's Awards

Queen’s AwardsThis year’s Queen’s Awards for Technological Achievement were dominated by developments in the realm of electronic technology. Electronics Weekly takes a look at a selection from the royal box Chassis-less micro-satellite concept puts SST into orbit Surrey Satellite Technology (SST)has been given a Queens Award for Technological Achievement in recognition of its development of the micro-satellite concept. Spun out of the University of Surrey, at a time when many said microsats could never do anything useful, the company now has nine of its minuscule creations in orbit. The satellites have no chassis. Instead they are made from a series of flat box-shaped modules stacked one on top of another and held together with long bolts. Modules available include: computers, receivers, transmitters, camera controllers, GPS receivers and power supplies. The module size of 30cm x 30cm determines the horizontal dimensions of the satellite and they finish-up around 60cm tall, although the exact height depends on the mix of modules which vary from 2 to 5cm thick. Power comes from four solar panels attached to the spacecraft’s sides. An ‘earth observation module’ containing cameras and antennas sits on top and on the bottom is the launch support bracket and a 3.5kg weight on the end of a 6m pole. This last assembly uses gravity to keep the microsat’s earth observation module pointing at the ground and is one of the neat positioning devices which remove the need for chemical thrusters.
Rotation about a vertical axis is controlled by switching coils on and off, causing the satellite to act like a compass needle. Any tendency to swing like a pendulum is suppressed using the same coils in conjunction with the vertical and horizontal magnetic field available when the microsat passes over the earth’s poles and equator respectively. Polymer lining goes deeper… As micromachining is becoming an accepted way of producing sensors and actuators, the need is increasing for an etching process that can produce straight-sided structures and deep parallel-sided holes. There are several existing methods, but all suffer from loss of precision as structures get higher and holes get deeper. The problem is that all etchant processes cut sideways while they cut down, or fail to etch into corners properly. The result is holes get wider or narrower as they go down. Surface Technology Systems (STS) of Newport does not claim to have developed a perfect solution, but it reckons that its advanced silicon etch (ASE) is the best of the bunch. It can produce holes nearly 40 times deeper that their diameter and silicon walls with 90? ?2? sides. STS uses a cyclic process. Etching, using a dry plasma process, is relatively conventional. The difference is that periodically the sides of the structure or hole are covered with a layer of polymer that protects the newly exposed vertical surface at the bottom of the cut against erosion. The polymer also coats horizontal surfaces, but its chemistry is chosen to be eaten away quickly under the direct onslaught of the plasma etch. The polymer is also eroded on the vertical surfaces, however the periodic polymer re-coating prevents the silicon being touched.
Careful balancing of all parameters in the process result in accurate results. At an etch rate of 3?m/minute, the process yields an anisotropy of greater than 99 per cent, vertical smoothness of better than 0.25?m amd horizontal flatness of greater than 0.1?m. Alchemist stops picture judder Digital television systems specialist Snell &Wilcox has picked up its sixth Queen’s Award. This time in partnership with the BBC for a video picture motion compensation system called the Alchemist phase correlation converter. When broadcasters and TVproduction companies compress or manipulate their video pictures they cannot tolerate any degradation in picture quality. Video engineers have attempted to tackle the problem of manipulating pictures showing motion but have created unwanted artifacts such as judder and loss of definition. The way round this is motion compensation techniques whereby the processing system predicts and tracks picture motion. There are a number of approaches to video motion compensation including a simplified version used in the MPEG and H.320 videoconferencing standards. A joint development programme between the BBCresearch labs and Snell &Wilcox has created a higher level of motion compensation using the technique known as phase correlation (PhC). The digital signal processing algorithm used in PhC identifies motion in the television picture using speed and trajectory measurements in real time. PhC algorithms perform fast fourier transforms on large areas of the picture to analyse the phase differences of their two-dimensional spectra. Because PhC works in the frequency domain rather than the spatial domain, it has the advantage of measuring only the movement of the picture, not the picture content itself. This minimises data processing.
With this information it is possible to predict the motion within the picture from frame to frame. According to Snell &Wilcox, the power of the PhC approach is the accuracy with which it can track picture motion, even in rapid movement sports shots without picture judder or loss of definition. Motorised comms antenna gives broadcasters mobility Advent Communications has gained recognition for its motorised satellite communications terminal that is already used by news agencies and broadcasters around the world. An important feature of the terminal is that the RFtransmitter/receiver circuitry, the up-converters and power amplifiers are mounted directly onto the antenna system. According to the company this has the benefit of reducing the systems waveguide losses to a minimum thereby improving transmitter efficiencies and receiver sensitivity. Called Newswift, Advent’s system is designed as a small, power efficient terminal that can be easily carried and deployed by journalists and the like around the world.
Versions are available that operate in the C-, Ku- and direct broadcast satellite frequency bands. It can be operated on any digital broadcasting transmission standard such as MPEG2-DVB(4:2:2), as well as being suitable for voice, video and data transmissions. Other technological Queen’s Award winners are: DRS Hadland : 100,000,000 picture per second camera. ETAL : High-speed vacuum encapsulation process. University College London and Otodynamics : Electronic hearing test. SEOS Displays : Digitally-enhanced multi-projector large screen displays. Smiths Industries : Low-weight civil aircraft power management system. Stewart Hughes: Helicopter vibration analyser.

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