By J.R. Wilson
MARLBOROUGH, Mass. - Executives of Raytheon Electronic Systems of Marlborough, Mass., believe they can have the joint Federal Aviation Administration (FAA)/ Department of Defense (DOD) Digital Airport Surveillance Radar (DASR) system back on schedule by mid-1998, despite a nearly four-month delay during which a contract award protest was heard and rejected.
DASR involves updating as many as 213 domestic and overseas radars - 120 FAA and 93 DOD - through the next decade at a potential contract value of $619.9 million. DASR is critical to efforts to upgrade military and commercial air traffic control systems.
Working on the DASR project are the U.S. Air Force Electronic Systems Center at Hanscom Air Force Base, Mass., which is also acting on behalf of the U.S. Navy, and the FAA, where it is designated the ASR-11.
DASR will provide terminal area primary radar surveillance of aircraft out to 60 nautical miles and secondary radar coverage as far from the transmitter as 120 nautical miles. Replacing existing ASR-7 and ASR-8 radars, the new system will interface directly with another joint FAA/DOD modernization program - the Standard Terminal Automation Replacement System (STARS) - also under contract to Raytheon.
"We`re going with solid-state S-band transmitters, which means the colistron tubes of the past are being replaced with transistorized transmitters," says Tony Polise, Raytheon radar programs manager. "We invested our own capital in developing this in the early 1990s and have been selling it since 1992."
As with all recent FAA efforts to pull its air traffic control system out of the computer Dark Ages and into the 21st century, all DASR elements must be part of an open architecture, with upgrades of hardware and software as simple as possible.
Open architecture
"We`ve been evolving technology as new products come out and that is one thing the government wants us to keep on doing," Polise says. "They don`t what to get into a mode where they are stuck with 20-year-old technology, so our system is based on commercial processors." Single-board computers embedded on the primary radar are based on the Motorola 68000 family of microprocessors - most likely the 68060 on production units - and those in the secondary radar are based on the Intel X86 family - most likely Pentium at production, he says.
DASR is a UNIX-based system using the Motif and X-Windows graphic user interfaces for maintenance and surveillance displays. From a technological point of view, the only advanced technology is the solid state system; the rest of it is commercial off-the-shelf (COTS), Polise says.
In addition to the radars, the contract calls for a maintenance set, communications capability between radar and display sites and site towers, antennas, engine generators, and shelters (as required - DOD leaders are looking primarily at shelter-based systems for the Navy and Air Force, while FAA officials will use pre-engineered, new or modified existing buildings). DASR also will be integrated with existing automation systems and with STARS.
By moving from the analog ASR-7/8 outputs to digital, DASR outputs can perform a number of new or improved tasks, such as superimposing aircraft identification or weather data for the air traffic control display.
"We`re required to provide six-level precipitation data that is National Weather Service compatible; the existing system is two-level," Polise says. "This denotes the level of reflectivity - which tells you how much rain is coming down or is in the clouds - and, based on the storm intensity, they may route aircraft around it. With a two-level system, a controller could not always tell the intensity of a storm system or cloud layer; with a six-level, he has better information and greater capability, such as isolating high-intensity cells on the edges of a generally low-intensity storm system. By not just diverting all aircraft around any storm system, they now can guide them through a system within 60 miles of the airport, thus improving efficiency and reducing the amount of time aircraft spend in flight and circling before landing."
The contract calls for the first operational tests to begin in early summer 1998 when the first two preproduction test units are to be delivered to Eglin Air Force Base, Fla., and to the FAA in Stockton, Calif. A third test asset also is to be delivered to the FAA training academy in Oklahoma City to prepare trainers and operators prior to the first production system deliveries. The production option will activate in late 1998, but Polise says he believes he can move that schedule up to wipe out most of the delay from the protest.
Lost time
"Anything we were doing as part of our product line continued, but all efforts relating to the government were halted for almost four months," he notes. "We`re discussing with the government how to make up the four months slippage. I think the government would like to see it completed so we can exercise the FY98 production option.
Raytheon officials will provide program management, systems engineering, and design support on DASR. The primary surveillance radars are from Raytheon Canada of Waterloo, Ontario. The Raytheon Service Company will provide site design and installation, training and maintenance support from its Burlington, Mass., headquarters. A subcontract for automation interfaces went to Sensis of Dewitt, N.Y., and competitive bids in the works for the towers, shelters, antennas, and pedestals (with awards on the last two targeted for early February).
Raytheon executives based their DASR bid on more than 60 solid-state primary radars and more than 180 monopulse secondary surveillance radars worldwide, the largest of which was the Canadian Radar Modernization Program (RAMP) procurement of 41 en route and terminal systems in 1984 to 1990.
"We`re on our fourth build on the primary radars and our eighth build on the secondary," Polise says. "The primary is second-generation solid state S-band and the secondary is fourth-generation monopulse L-band. We`re not using the same equipment [as RAMP] - that was our first-generation solid state, for example - and this is a much more open architecture, but the basic technology is the same."
They also have gone to very large scale integration electronics, known as VLSI, on the secondary radars, which eliminated many circuit cards, and significantly cut cost even as the technology itself improved.
"When you look at the specs that were imposed, there were no mil-specs," Polise explains. "In a lot of the older procurements, they would ask for mil-spec - ceramic and not plastic parts, for example - but here they were really going for COTS technology. The plan is to be identically supportable between the DOD and FAA. The only ruggedization will be on some sites - mostly outside the United States - where they may have radomes around the antennas to protect them from harsh environments.
DASR will feature automatic fault detection and isolation, in which faults show up as graphics on a display. Clicking on a red graphic (indicating a problem) will show the card slot involved and what needs to be replaced. And with the use of transistors and multiple redundancy in a solid-state system, if a power supply or modular transmitter fails, it can be replaced while the system is still running rather than being forced to switch to another transmitter and shut down the one being repaired, as it the case with the current system.
