Addressing two of the Patriot incidents, the briefing document-a PowerPoint presentation of "insights" drawn from fratricide incidents during Operations Iraqi Freedom and Enduring Freedom produced by the Army Center for Lessons Learned-says positive electronic means of identifying airborne objects have been demonstrated to have "low reliability."
Jammed communications, aircraft transponders that cannot communicate with air-defense crews and some "atrophied" air-defense skills are identified as problems by the briefing, which urges using "procedural methods" of identification.
"Positive" methods of identification generally use electronic means, including radar, friend-or-foe identification transponders, computers and communications equipment, while "procedural" methods rely on tactics, techniques and procedures such as predesignating safe areas for friendly aircraft.
The briefing also urges strict adherence to procedures for identifying and targeting suspected enemy activity, as well as having "robust communications" and standardized battlefield identification systems.
The document further recommends the systems be operated manually and not put on automatic.
"Every effort must be made to avoid autonomous fire units," it said.
The low reliability of the Patriot's identification capability already was known, according to the briefing.
"Past exercises and tests run in SWA [Southwest Asia] indicate the percentage of aircraft that [are positively identified] remains too low. There are too many points of failure," it says.
Philip Coyle, the former Defense Department director of operational test and evaluation, said joint-service testing as far back as the early 1990s identified communications problems associated with air-defense systems when attempting to identify a friend or foe.
"This clearly was not a priority in the development of this equipment and should have been," he said.
The Patriot system currently is the Army's only operational ground-based theater air-defense system.
Designed originally for defense against enemy aircraft, the Pentagon has invested $3 billion since the 1991 Persian Gulf War to improve the Patriot's ability to track and destroy ballistic missiles, according to a recent congressional study.
The briefing document was prepared by the Army center following Operation Iraqi Freedom to help quickly disseminate lessons learned from various friendly fire incidents.
It does not say explicitly what the causes were for the three incidents, which led to the deaths of two airmen. The Army and the U.S. Central Command have been conducting investigations, and so far no reports have been released.
During the conflict, two coalition aircraft were believed shot down by the Patriot-a British Tornado fighter aircraft on March 24, killing two pilots, and a U.S. Navy F/A-18C Hornet fighter on April 2, killing the pilot.
The Tornado reportedly failed to re-enter Kuwaiti airspace from Iraq in a predetermined zone cleared for friendly aircraft and reportedly carried an identification beacon that could not communicate with the air-defense system.
The third incident involved a U.S. F-16 which was targeted by a Patriot system left by its crew to operate automatically so they could take cover, and the radar mistakenly identified the aircraft as a foe.
Many of the briefing's recommendations identify problems not necessarily specific to the Patriot, but more generally to difficulties created by the U.S. military's increasing emphasis on consolidating multiple pieces of surveillance data to provide a more complete picture of the airspace, said Coyle.
"Basically, the problems stem from a lack of interoperability and from fusing together data from many different sensors in a complex battle space. It's a tough problem requiring interoperable equipment and sophisticated computer routines that can sort through what's happening," he said.
In an official report in 1995, Coyle wrote that problems in then-recent tests stemmed in part from different services and weapons systems using various message formats, standards, terminology and algorithms for correlating target-tracking information.
The briefing document says the previous tests and exercises showed identification transponders on aircraft became jammed because they were overloaded by electronic requests for their signal.
"Communications continue to be a choke point, and not all elements on the battlefield have continuous access to the datalink air picture," the briefing says.
The briefing says better capabilities are needed to allow air-defense controllers to directly communicate with aircraft.
"More emphasis must be placed on designing the theater voice and data communication architecture," it says.
The briefing also cites a weakness with Patriot operators.
"Over the past 12 years, Patriot Tactical Control Officers have been trained to focus primarily on TBMs [theater ballistic missiles], and some skills necessary to maintain situational awareness have atrophied. Maintaining friendly and enemy SA [situational awareness] for all air tracks is critical," it says.
The Army is reportedly stepping up development of a new identification system called Blue Force Tracking, as a result of the war, Federal Computer Week reported recently.
The Senate Armed Services Committee in a report earlier this year expressed concern that "longstanding" combat identification and friendly force tracking needs have not been pursued "in the most expeditious manner."
"Recent military operations have further demonstrated the high risk of fratricide on the modern battlefield and re-emphasized the need for comprehensive, interoperable combat identification and blue force tracking architectures," it said.