JSTARSFrom the manual (read me):
" pg. 53
The Joint Surveillance and Target Attack Radar System (JSTARS) is an aircraft which uses radar to locate and track ground vehicles. This aircraft can then downlink this information to your Threat and Tactical Situation displays. The presence of JSTARS is listed in each of your mission briefings. When a JSTARS support is available, it is noted in the friendly forces summary.
JSTARS information is made automatically available to you in missions where JSTARS are present. There is nothing you need to do in order to receive JSTARS data. The JSTARS aircraft itself is orbiting tens of miles away and will not appear on any of your displays. You won't be able to see a JSTARS aircraft either, you'll only receive its information.
JSTARS gives you the ability to detect enemy objects even when you do not have a direct line-of-sight to them. JSTARS relieves you of this burden. Essentially, all enemy objects, or at least those detected by JSTARS are made visible to you on your Threat Display. "