SPECIALHIGH-END EMBEDDED COMPUTINGdata-dependent operations. Other parts ofthe application, especially data-dependentoperations, are targeted to the generalpurpose processor, which is easier to programfor those types of algorithms. Thisstyle of application partitioning maximizessystem performance while keepingoverall development time manageable.Solution designSeveral approaches provide more capabilityin smaller physical configurations.The first is the use of dense packaging inphysically small but st<strong>and</strong>ard configurations.Another approach is the sharing ofprocessing across multiple sensors. Thistechnique provides multimission processingfrom a common set of processors. Thetechnique supports multiple payloads <strong>and</strong>provides time-sliced load-leveled solutionsacross a suite of sensors that operatevirtually simultaneously, providing shortyet effective periods where processingelements can be shared.For physically small but st<strong>and</strong>ards baseddesign requirements, 3U <strong>CompactPCI</strong> isa strong choice. It is a widely acceptedst<strong>and</strong>ard, maximizing configurationflexibility with a wide range of marketavailableproducts. The 3U <strong>CompactPCI</strong>connector offers outst<strong>and</strong>ing pin density;the J1 <strong>and</strong> J2 connectors provide enoughpins to support 32-bit PCI with additionalpins left over for sensor I/O. Because ituses PCI as the system bus, <strong>CompactPCI</strong>also delivers compatibility with systemsoftware components. St<strong>and</strong>ards-basedI/O flexibility can be further supportedwith a PCI Mezzanine Card (PMC) interface;PMCs are a common enhancementto 3U <strong>CompactPCI</strong> systems.Development of multimission computingpayloads provides significant opportunitiesto the platform primes as well as topayload developers in realizing increasedindividual sensor processing resourceswithin the SWaP <strong>and</strong> cost constraints ofthe platform.Example systemMercury Computer <strong>Systems</strong>’ MCP3 FCNmodule meets these requirements, deliveringhighly flexible signal processing capabilityin a space-efficient 3U <strong>CompactPCI</strong>format. (See Figure 2.) The MCP3 FCNemploys a 1 GHz PowerPC 7447 <strong>and</strong> aVirtex II Pro P40 FPGA. A Discovery IIbridge chip connects the two processingunits. The three avenues for off-boardcommunications <strong>and</strong> I/O are via:■ PCI bus on the J1 pins of the<strong>CompactPCI</strong> connector■ Digital Intermediate Frequency (IF)to the FPGA via a direct connectionfrom a subset of the user-definedJ2 pins■ PMC, which can communicatedirectly with the FPGA or throughthe Discovery II chip to thePowerPCTo develop application components targetedfor the PowerPC processor runningWind River’s VxWorks operatingsystem <strong>and</strong> using the Tornado operatingenvironment, engineers have access to amature set of Mercury tools, including theScientific Algorithm Library (SAL) withmore than 600 routines optimized for thePowerPC. For those parts of the applicationthat run on the FPGA, developerscan use Mercury’s FPGA Compute NodeDeveloper’s Kit, or FDK. This kit is a collectionof Mercury-developed IntellectualProperty (IP), build files, comm<strong>and</strong> linetools, libraries, headers, drivers, boarddescriptors, diagnostics, <strong>and</strong> consultingsupport, all focused on helping engineersefficiently create reliable FPGA-basedapplications.The MCP3 FCN board is also capable ofdeployment in harsh environments. It isavailable in both air-cooled <strong>and</strong> conduction-cooledversions <strong>and</strong> is optionallydelivered in either an IEEE 1101.1 orDRTi chassis. This type of space-efficient3U signal processing solution can bebuilt using powerful COTS components,including Mercury’s MCP3 FCN. It issmall enough to be used in smaller platformssuch as UAVs, <strong>and</strong> flexible enoughto perform multiple missions <strong>and</strong> interfaceto a variety of sensors.Figure 2ConclusionThe processing requirements of smallerUAVs can be met today with the carefulallocation of the requirements to the availableCOTS processing/adjunct elementsin smaller, denser yet st<strong>and</strong>ard packagingconfigurations. These systems canmeet the environmental challenges <strong>and</strong>performance requirements of affordableflyaway costs, appropriate reliability, <strong>and</strong>performance to support the multisensorrequirements within the platform’s SWaPconstraints.Bob Kahane is director of theSIGgnals INTtelligence/ElectronicWarfare (SIGINT/EW) segment forMercury Computer <strong>Systems</strong>’ DefenseElectronics Group. He heads thecompany’s RF Center of Excellence(RFCE) in Reston, VA, which providesfront-end products for the SIGINT,radar, <strong>and</strong> software radio segments.Before joining Mercury, Bob was atRaytheon’s Intelligence <strong>and</strong> Information<strong>Systems</strong> organization for 18 years.Bob is a graduate of the BrooklynPolytechnic Institute with a BS inapplied mathematics <strong>and</strong> an electronicengineering minor. He has completedmaster’s studies in business administrationat the American University <strong>and</strong>in electrical engineering at GeorgeWashington University.For further information, contact Bob at:Mercury Computer <strong>Systems</strong>, Inc.199 Riverneck RoadChelmsford, MA 01824Tel: 703-673-2720Fax: 703-673-2737E-mail: bkahane@mc.comWebsite: www.mc.com28 / <strong>CompactPCI</strong> <strong>and</strong> <strong>AdvancedTCA</strong> <strong>Systems</strong> / June 2005
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