Iraq could try to jam US communications and intelligence satellites in a war, but is unlikely to succeed, a senior US Air Force officer said.
However, Blaisdell acknowledged that not all US communications satellites are resistant to jamming and that there have been past incidents in which commercial satellites have come under attack by other countries. "They could possibly attempt," he said of Iraq. US reliance on satellites for military operations came into its own in the 1991 Gulf War and has since intensified with the advent of information age warfare. Satellites are now the linchpins in a system that fuses intelligence from all sources to create a common picture of the battlefield that can be accessed instantly by commanders in the field or leaders in Washington.
Military satellites provide high-speed communications, emit navigational beacons used to guide precision weapons to targets, track weather patterns and conduct overhead surveillance and reconnaissance. The army is now fielding devices to track their soldiers in the field, giving a commanders a clearer picture of where their forces are when they venture beyond radio contact, said Colonel Stephen Fox, who said about 1,000 of the devices exist.
The devices, which consist of transponders that transmit their positions via satellite, can be used to track vehicles or aircraft as well. Those used for tracking soldiers are carried in packs, or are hand held.

Source : http://www.spacedaily.com/2003/