Radar signal processing upgrades use embedded COTS hardware
Military radar designers are turning more and more toward Commercial Off-the-Shelf (COTS) signal processing solutions to modernize existing radar systems. (Photo courtesy of Lockheed Martin)
The capabilities of modern radio detection and ranging systems, better known as radar systems, are light-years ahead of where they were when radar was invented in the World War II era.
There are so many different slices and flavors of radar now, and the technology available today versus 5 or 10 years ago is night and day in terms of performance, says Rodger Hosking, Vice President of Pentek in Upper Saddle River, NJ. Radar system requirements coming out of the DoD put a tremendous demand on signal processing solutions that not only deliver compute performance, but that must be rugged and low power, he adds.
A major source for the ruggedization demands are Unmanned Aerial Vehicles (UAVs) that perform Intelligence, Surveillance, and Reconnaissance (ISR), Hosking says. The UAVS, which continue to increase in number, need rugged, light radar payloads with unique small form factor configurations that can operate in hazardous environments, he adds. Military customers also are interested in generating stealthy radar pulses that are difficult for an enemy to defeat, Hosking says.
The military wants higher and higher performance to be able to track multiple targets simultaneously and track every signal coming in, says Anne Mascarin, Solutions Marketing Manager at Mercury Computer Systems.
Turning to COTS
Because of performance requirements and the expectation of reduced funding, system integrators are looking to outsource radar signal processing tasks to COTS suppliers, says Jane Donaldson, President of Annapolis Microsystems in Annapolis, MD. Integrators are essentially wanting to do more with less, she says.
Where in the past they would use internal resources to develop signal processing boards, they will be forced to outsource because of lack of funding and possibly workforce reductions as well, she explains. Military system integrators also will want to use open architecture designs based on commercial standards as they are more cost-effective in the long run and easier to upgrade, Donaldson says.
The open standards tie so much to the spiral upgrade strategy the DoD uses, where there must be open standards or the spiral upgrade will not work, says Tom Roberts, Solutions Marketing Manager at Mercury Computer Systems.
System integrators want an open architecture at the board and chassis levels so they can actually plan out lower-cost technology insertions, says Eran Strod, Systems Architect at Curtiss-Wright Controls Defense Solutions in Ashburn, VA.
Advantage of GPPs and FPGAs
Two key enabling signal processing technologies for radar are the performance capabilities of General Purpose Processors (GPPs) such as Intel’s Core i7 family and the growing capability of FPGAs.
COTS GPPs are still the main processing tool for radar systems, and that probably will not change any time soon as Intel is continuing to make inroads into this space with high-performance processors such as the Core i7, says Doug Patterson, VP of Business Development for Aitech in Chatsworth, CA. The extra processing power is essential for new radar applications such as some K-band multimode radars that do not emit signals an enemy could detect, he adds. For more information on Aitech signal processing systems, visit www.rugged.com.
FPGAs and GPPs are not virtually exclusive either; new radar designs are making use of both components to meet substantial processing demands of modern radar systems.
There is a need to have the FPGA and GPP work together, Pentek’s Hosking says. The FPGA is good for doing parallel operations very quickly, but is not good at sophisticated analytical type tasks, which is where a GPP comes in, he adds. For more on Pentek’s FPGA signal processing products, visit www.pentek.com.
“We see virtually every radar program using a mix of general purpose processors and FPGAs in radar systems,” Roberts says.
FPGAs are phenomenally good at dealing with the problem of power, as they are only tuned to do what you want them to do, Jeff Milrod, President and CEO of BittWare in Concord, NH, says. They also are better at doing data independent processing where you do the same thing every time, he adds.
FPGAs are good at taking data and filtering it and sending it out to other processors that do a better job of interrogating data, Curtiss-Wright’s Strod says.
Many FPGAs also have digital signal processors built into them as cores, which enables designers to pack more processing capability into an even smaller footprint, says Ian Stalker, Product Manager at Curtiss-Wright Controls Defense Solutions. For more on Curtiss-Wright’s signal processing and FPGA solutions, visit www.cwcembedded.com.
The major drawback with FPGAs is the difficulty in programming them with VHDL. It is harder, more expensive, and more time consuming than programming in C or C++, Donaldson says. Also, there are fewer VHDL programmers than C programmers, she adds. With the DoD cutting back funding, military radar designers will want to find more cost-effective alternatives to VHDL for programming FPGAs, Donaldson continues. “Annapolis offers a product called CoreFire, which enables engineers to program FPGA boards very quickly and get them completed much faster.”
BittWare also has a new solution aimed at cutting down on FPGA development time (see sidebar on page 35).
The Annapolis CoreFire is a data flow-based tool that eases FPGA design by allowing developers to automatically generate intermodule control fabrics and use a drag-and-drop graphical interface. The tool also has hardware-in-the-loop debugging and can easily port completed applications to new technology chips and boards, according to the Annapolis website at www.annapmicro.com.
FPGAs key in Air Force long-range surveillance radar upgrade
Engineers at Lockheed Martin in Syracuse, NY combined GPP and FPGAs and programmed their FPGA board with the Annapolis CoreFire tool for an upgrade of 29 U.S. Air Force AN/FPS-117 long-range surveillance radars – 15 in Alaska, 11 in Canada, and one a piece in Hawaii, Puerto Rico, and Utah. The radar system makes up the Air Force’s Atmospheric Early Warning System.
The upgrade program, dubbed the Essential Parts Replacement Program (EPRP), has Lockheed Martin engineers replacing and updating all the radars’ data and signal processors to state-of-the-art commercial technology to help extend their operational lives through 2025, Chris Atherton, Technical Director for Long Range Radar at Lockheed Martin, says. The radar site’s secondary surveillance radar, which is used for air traffic control purposes, will also be modernized.
This is not a capability upgrade for the Air Force, but more an effort to “sustain existing missions in a better, faster, cheaper manner,” Atherton says. The mission of this radar system has not substantially changed even with the upgrade, he continues. It is an air defense early warning radar system covering the periphery of Alaska and northern Canada with its main customers being the Federal Aviation Administration (FAA) and the North American Aerospace Defense Command (NORAD), Atherton adds.
“We have an open architecture approach to L-Band radars that enables technology refresh long-term for sustaining a fleet of more than 175 radar systems,” he says. At the design level, the goal is to not only decrease failures but to decrease the Mean-Time Between Failures (MBTF) too, he adds.
The older system was not an open architecture, by any means. “We literally made our own computers that used a digital data processor, a memory board, and our own operating system to handle the demands for radar signal processing.
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With this upgrade, “We replaced five cabinets measuring 6 feet by 3 feet by 3 feet that were completely filled with homemade electronics” with 15 COTS cards with “substantial commercial processing capability,” Atherton says. “We used COTS technology wherever possible, as it was the easiest and least expensive way of supporting the system over the next 15 years. The processing is done via an Oracle Sun Netra 5220 server – which has an UltraSPARC T2 processor – and a 10 Gigabit Ethernet interface is used to move the radar data, Atherton says. The Oracle devices have plenty of horsepower and are very efficient parallel machines, he continues. The operating system is Solaris, Atherton adds.
“We also used a Wildfire FPGA board from Annapolis Microsystems that uses their CoreFire FPGA development tool” to program the boards to do the digitization and digital filtering inside the radar system, Atherton continues. “They’ve taken what was a row of cabinets of electronics and fit it all onto a 6U VME board.
Thanks to CoreFire, “We were able to use the same software folks [who] worked on the GPP on the FPGA, instead of having to employ a VHDL specialist,” Atherton says. “This also gives us advantages for when we migrate to the next generations of their board.”