Defence

Modern defence systems rely on high performance electronic hardware. Plextek has extensive experience in the design of defence electronics. We are familiar with obsolescence management and the design of defence products using Commercial Off The Shelf (COTS) components. We are able to use our experience in the development of cost competitive commercial products to assist defence equipment manufacturers in the design of defence electronics, so allowing them to make significant cost savings. This model has been proven on a number of high volume military applications currently in service with the British Defence Forces. We are also able to offer rapid development programmes or provide enhancements and essential modifications to existing equipment to meet Urgent Operational Requirements (UOR). Examples of some of the defence programmes that we've undertaken include:

• Various phased array Radar design and development programmes
• DSP based multi-channel receivers
• IFF Transponder design
• Assessment of technology options for Unattended Ground Sensors (UGS)" to "Communications and Processing platform for Unattended Ground Sensors (UGS)
• 2-18GHz receiver front-ends for ESM systems
• Sonobuoy communications links
• Telemetry and radar development for Unmanned Aerial Vehicles (UAVs)
• Design of wideband, digitally synthesised, chirp generator for radar applications
• Signal processing for various airborne radar applications
• Microwave and mm-wave subsystem developments
• Design and supply of a fibre optic communications system

More details on a selection of these programmes are provided below:

Unattended Ground Sensors (UGS)

Plextek has developed a powerful, but compact, autonomous processing and communications platform for Unattended Ground Sensors (UGS). Plextek’s client was developing an UGS that needed to acquire, store, process and transmit data from audio, video and other sensors. All of this functionality needed to be packaged in to a compact product, to operate from a battery, and be remotely deployable. Our solution (shown in the photograph to the right) utilised small COTS radio products together with a bespoke CPU system and a number of personality modules to provide specific interfaces for the sensors.

The UGS can make use of a wide range of sensors. Typical examples include microphone arrays (for direction finding), PIR sensors and video (optical and/or infrared). The communications link, for transmitting data from the remote UGS, makes use of 802.11a/b/g technology. This was chosen to provide the best balance of bandwidth, range, resilience to interference and channel blocking.

Sonobuoy Telemetry

Plextek were commissioned to design and implement a new UHF Sonobuoy command receiver architecture. For the new design to be a good business solution it needed to offer lower parts cost, improved performance and greater ease of manufacture and test. To meet these objectives, Plextek designed a single conversion superhet receiver based on a pager architecture, which included the duplexer on the same PCB.

Other high cost components, such as the IF filter, were replaced with low cost lumped element distributed networks.

Following this success, Plextek were asked to design a low cost analogue transmitter. In response to this, a superhet transmitter was designed around a dual synthesiser solution intended for use in cellular telephone systems.

IFF Transponder

Many IFF protocols have developed in an evolutionary manner and the traditional approach to implementing these has been to add a new processing card for each mode or set of modes. The processing card designed by Plextek has the revolutionary approach of encompassing all the current requirements into a single card using re-configurable techniques. (Right, IFF Transponder pcb, developed by Plextek Ltd for Raytheon Systems Limited, photograph by kind permission of Raytheon Systems Limited)

Due to the complexity of the requirements, it was decided that a flexible platform implementation was required, to help minimise development time and “design in” the capability to upgrade and modify the equipment, as and when future requirements emerge. The appropriate use of DSP, FPGA, FLASH memory and CPLD technology avoided the need for expensive and potentially destructive physical rework. In another development, a Plextek design is being qualified for use in Hawk and Tornado fighter variants

Defence Products Available from Plextek.

Plextek has utilised the extensive defence electronics experience of the company's engineers to undertake two internally funded product developments. Both can be customised to meet a client's specific requirements and both are available either as finished product or on a license to manufacture basis:

• “Diablo” is a family of Digital Receivers that feature a highly integrated, very high performance DSP board and a variety of PMC modules for radar, radio and modem applications. For more information Plextek's Diablo digital receiver design click here.
• “Blighter” is a man portable, low power, low weight, E-scan radar. The antenna is low cost, low profile and robust and is an integral part of the radar assembly. A wireless link is provided to allow the radar display to be viewed on one or more remote PDA's or PC's. For more information on Plextek's Blighter E-Scan Radar design click here.

To discuss how we can help you with your development requirements please contact us