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Military Microwaves Supplement
Recent Advances in Radar Technology
Using Calibration to Optimize Performance in Crucial Measurements
US and Europe Consider Astronomical Link
The US and Europe are considering merging their plans for next-generation, large-scale mm-wave radio telescopes. Currently, US astronomers are proposing what is being referred to as the US millimeter array (USMMA), while the Europeans are working on what they term the large southern array (LSA). The two concepts differ in that the USMMA proposal calls for a circular array of 40 8 m antenna dishes that would operate together as an interferometer, while the LSA would utilise a smaller number of 16 m antennas, which reportedly would provide a collection area five times larger than that of the American system. In addition, the USMMA is designed to view large extended sources at high frequencies, while the LSA is aimed at observing very distant, faint objects (such as young galaxies) radiating at above submillimetre wavelengths. Following meetings at the National Radio Astronomy Observatory in Charlottesville, VA, the two sides agree that a jointly funded array should be built at Chajnantor, a 5000-m-high site in Chile’s Atacama Desert. No decision was reached on whether to use both of the proposed dish sizes or to develop a common system that would accommodate both of the outlined approaches. The total cost of developing such an observatory is estimated at $400 M. In terms of proposal maturity, the USMMA is more advanced with US National Science Foundation funding of between $5 and $9 M proposed for FY 1998. If approved by both the House of Representatives and Senate and assuming no firmed-up cooperative programme supersedes it, the higher figure would allow USMMA development to proceed to the production of prototype antennas, receivers and other necessary subsystems by 2000. Thereafter, the system is scheduled to be operational by 2006. The estimated cost of the LSA proposal is $350 M with no project funding available until at least 2000. Further cost reductions on an international site may be achieved if the Japanese (who are developing their own array concept) can be persuaded to join the evolving US/Europe teaming arrangement. However, bilateral US/Japanese talks have yet to produce any results.
Aero-1 Moves Forward
The International Maritime Satellite Organisation (INMARSAT) is ramping up to full-scale implementation of its new Aero-1 satellite telephone, fax and data service for short- and medium-haul civil aircraft. Based on the latest INMARSAT-3 satellite constellation, the system offers 4.8 kbps telephony, 2.4 kbps fax and 2.4 kbps real-time data communications facilities. The complete package allows for the reception of news and weather broadcasts, point-to-multipoint data broadcasting and interactive passenger services. Aero-1 also is designed to be used as an air traffic control tool and is scheduled to be approved for future air navigation services use by the International Civil Aviation Organisation by the end of 1998. The first Aero-1 service providers are Skyphone and Satellite Aircom. Satellite Aircom has signed up the German carriers Aero Lloyd and Air Berlin together with Indonesia’s Sempati Air as customers for the new service, which is referred to as Aircom-1. Aero-1 avionic equipment producers include Rockwell Collins, a consortium of Honeywell and Racal, and Thrane & Thrane. Airbus and Boeing/McDonnell Douglas are reportedly interested in developing the airframe.
UK Begins Selection of Merlin HC.3 DAS
GEC-Marconi’s Sky Guardian 2000 radar-warning receiver and Hughes Danbury’s model AN/AVR-2A(V) laser warner have been selected for use in the defensive aids subsystem (DAS), which is scheduled to be installed aboard the UK royal air force’s next-generation Merlin HC.3 tactical transport helicopter. The Sky Guardian 2000 receiver incorporates a four-port antenna array, a half-sized air transport racking processor, and cockpit control and display units. System features include long-range threat detection, automatic emitter identification, integral data recording facilities and a persistent display mode for fleeting signals. The model AVR-2A(V) laser warner offers 360° coverage and can detect and categorise laser sources that are used as range finders and designators and as guidance mediums for beamrider missiles. In related news, Tracor’s model AN/ALE-47 chaff and infrared decoy flare dispenser system has been selected for use on an unidentified variant of the Merlin helicopter. This programme involves UK contractor Joyce Loebl, who handles Tracor dispenser activity in the UK.
Philips Launches World Standard TV Microcontrollers and New MR Pre-Amp
Netherlands contractor Philips Semiconductors has launched a range of microcontroller devices that it claims provide a truly global capability for television applications. Use of the model 80C51 core and pin alignment configurations provides software and hardware compatibility with current global television standards. Alongside functions such as remote control, keypad handling, tuning and video, sound and deflection control, the new devices feature on-screen display (OSD) facilities for menu control. Included in the OSD package are the ability to handle Chinese and Japanese ideograms, teletext characters for Fastext and similar systems, and line-21 decoding for closed captioning. Software support is included for automatic tuning and sorting, automatic channel installation, and electronic programme guide and violence chip applications. In addition, the company has launched a 10-channel pre-amplifier for single-strip, magnetoresistive (MR) read/inductive write heads with performances of up to 300 Mbps. The new model TDA5357 pre-amplifier is programmable and incorporates thermal asperity detection and recovery for the detection of potential damaging particles on disk. The device features a noise rejection value of 65 dB at 100 MHz for both the common-mode and power supply rejection ratios, and utilises only one external resistor with integral filtering and direct current blocking capacitors. A chip selector feature reduces the number of serial port control lines and facilitates multiple pre-amplifier integration. Device programmability includes operating mode (read/write, standby and sleep); head selection; bias and wire currents; gain, gain boost and gain attenuation; write driver compensation capacitance; and wire current inhibition and servo write head selection. Other features include integral read/write amplifiers, serial interfaces, digital-to-analogue converters and –4.7 V/+5 V control circuits.
Australia Weighs Tactical Surveillance Radar Choices
The royal Australian air force has reportedly short-listed three candidates to meet its future tactical air-surveillance radar requirement. The equipment specification issued requests both a conventional air-defence capability and the capability to detect and track theatre ballistic missiles. Contenders include France’s Thomson-CSF, the US’ Lockheed Martin and Israeli contractor Elta Electronics. Thomson-CSF is offering its E-/F-band (2 to 4 GHz) Master-T three-dimensional equipment, which incorporates a semi-active antenna and an instrumented range of 440 km. Lockheed Martin is proposing a variant of its D-band (1 to 2 GHz) model AN/FPS-117 radar, which is capable of detecting tactical ballistic missiles and targeting antimissile missiles against them. Elta Electronics is offering a transportable version of its D-band air defence advanced radar system, which incorporates an active array and is credited with a detection range of 370 km. This active-array technology stems from Elta’s Green Pine radar, which is used in the US/Israeli Arrow theatre missile defence system.
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