The British Army has been testing technologies — including RFID tags — that could reduce casualties from 'friendly fire' incidents.
Earlier this month Nato's Operation Urgent Quest exercise tested the potential of a number of combat identity systems under battlefield conditions on Salisbury Plain, with 800 troops, 94 combat vehicles and nine aircraft putting a series of technologies through their paces.
US Army colonel Bill McKean told ZDNet UK sister site silicon.com no single system would solve the problem of friendly fire.
A lot of time and money has been spent looking for a single "silver bullet" system, he said: "It needs to be a family of complementary solutions, fielded to different degrees by different nations that can work together."
And while many of the technologies are bulky at the moment, similar technologies for individual troops could soon be on the horizon: "As these technologies progress they all progress towards miniaturisation and that's good for the dismounted soldier," he added.
One of the technologies being investigated is radio frequency tagging, according to lieutenant colonel Tony Sobrero of the US Airforce Airwarfare Battlelab. But the tags being tested by the military are larger and more rugged — and much more expensive — than the ones being tested by retailers.
Energy sent out by an aircraft's radar is used to illuminate the tag, which can then send back location information in the reflected radar return.
The smallest of the tags being tested is powered by four AA batteries.
Sobrero explained: "Typically aircraft are very good at identifying other aircraft but less good at identifying ground assets. We are demonstrating that we can illuminate [a tag] and get information back."
One of the big benefits of using the tags is that there is no need to update the radar hardware, he said.
He added: "You could use it for tracking friendlies or high value assets you don't want to target, like a hospital.
"It's a fairly inexpensive technology that can be used on a number of platforms. With that little antenna and four AA batteries you can get a return at 80 miles."
The next step is to develop the tags so they don't respond to enemy radar, and to add encryption and anti-tamper features.
Sobrero added: "These are things to think about and we're not there yet."
Operation Urgent Quest also showcased other identity systems including a millimetre-wave based technology called Battlefield Target Identification Device (BTID). The BTID interrogator — for example mounted on a tank — sends an encrypted message to a vehicle that it wants to identify. If the unknown vehicle has a BTID transponder, this will unscramble the message and then reply with its own encrypted message, which will identify it as a friend.
The system allows commanders and gunners to investigate a target without having to aim the main gun at it — which could be considered threatening.
It has a range of 5km for tanks, but when fitted to a Harrier Jump Jet it has a range of 20km. It could be in service on the battlefield by 2010.
Other systems tested include one that will help forward observers identify targets and friendly units within the same footprint in a matter of seconds using radio broadcasts.
Another system was laser-based and small enough to be mounted on a soldier's rifle.