The Army in its fiscal 2017 budget request plans to spend $35 million to begin a search for upgraded Patriot missile defense radars that Raytheon [RTN] has already developed with more than $150 million of its own money.

A program buried in the Army’s research, development, test and evaluation funding requests for fiscal 2017 called the lower tier air and missile defense (LTAMD) capability seeks to integrate a gallium nitride array antenna onto a baseline Patriot battery.

Meanwhile, Raytheon has completed assembly of its actively electronically scanned array (AESA) missile defense radars and is shopping for a launch customer for the upgrade among owners of the 200-plus operational Patriot batteries.

The company unveiled the first prototype of the Patriot AESA radar at a trade show in March, where program director Doug Burgess said the capability and reliability improvements it offers garnered interest from the U.S. Army and international Patriot customers.

Raytheon's Patriot is an example of an Army air defense system. Photo: Raytheon
Raytheon’s Patriot is an example of an Army air defense system.
Photo: Raytheon

LTAMD seeks to “provide studies for initial concepts and performance capabilities to the implementation of an active electronically scanned array (AESA) transmitter/antenna into the Patriot radar,” the Army’s budget justification reads. “These assessments are needed to refine user community expectations and requirements, to provide overmatch against the emerging threat and to prepare a viable set of requirements to support a competitive modernization competition.”

 The radar upgrades will allow “increased radar operating ranges thereby maximizing the inherent PAC-3 missile segment enhanced capabilities to engage threats.”

Plans are to spend an initial $35 million in fiscal 2015 to begin materials development, conduct an analysis of alternatives and a business case analysis, according to the Army documents. Spending shoots up to a high of $93 million in fiscal 2018, then levels out to $85 million through 2021.

The Army’s timeline for LATMD development calls for a milestone A decision late this year. A decision to begin engineering and manufacturing development (EMD) is scheduled in the second half of 2019, meaning fielding of radars under the Army program is perhaps a decade in the future. 

Raytheon has built only one Patriot GaN AESA, but the technology is at manufacturing development level eight, meaning ready for production. The prototype has completed several hundred target acquisition drills in which it locks onto overflying airliners or other “targets of opportunity” to demonstrate its operational readiness. 

“With the prototype, we’re showing that we are there now,” Burgess said.

Among the capability upgrades, GaN AESA improves target detection and identification and reliability of the overall system while reducing power consumption by 30 to 40 percent, Burgess said.

“All of those things resonated with anyone who came by the booth, particularly those who were familiar with Patriot–either current operators, retired operators and general officers,” Burgess said of attention the array received at the AUSA symposium in Huntsville. “There was certainly a lot of interest at AUSA from our international partners on the fact that this could be an upgrade to their existing radar sets, particularly where they would not have to send their units back to Mother Raytheon in the United States.”

The United States does not have a published requirement to upgrade its Patriot batteries to 360-degree coverage, but some international Patriot users do. Raytheon has received permission to export the AESA GaN technology, but has no firm orders.

The company plans to perform the radar upgrades at depot level for foreign Patriot operators, though not in the field on operationally deployed batteries, he said. Installing an AESA radar on an existing Patriot does not require extensive software modification, Burgess said.

“We’ve pulled together a lot of new items, specifically the whole GaN AESA panel,” he said. “So we need to go through the paces of characterizing that and continue to step it up to full-power operations stressing the different capabilities.”

Raytheon has invested $150 million in replacing the gallium arsenide (GaS) in Patriot’s advanced electronically scanned array (AESA) radars with gallium nitrate (GaN). The new material boosts the radar’s performance and reliability while making it more affordable to operate, if more expensive up front. Including government investment in GaN technologies, the total investment is around $300 million, Burgess said.

“In terms of the technology, it’s ready now,” he said. “There is not some long development process that has to go on to see if gallium nitride and AESA technology can be used by the Patriot system.”

A Patriot missile battery’s mobile radar has a large array on the front that includes 109 receiver units in its face. Each is an independent, electronically controlled radar antenna that is bi-directional, so it performs both tracking of incoming threats and communication with the interceptor missile. At the rear of the radar unit are two quarter-sized arrays that provide radar coverage from the sides and rear. All three can be upgraded with AESA GaN or just the main array.

The upgraded GaN arrays are at technology readiness level eight, meaning they are ready to begin production once a launch customer places an order.

During the redesign of the Patriot radar array, Raytheon was able to free up some space for direct integration of the Northrop Grumman [NOC] integrated air and missile defense battle command system (IBCS). Overall, the GaN AESA upgrades enhance capability while lowering cost to operate, which mesh with the Army’s stated intention of doing more with the Patriot batteries it has on hand.