One Gripen can provide radar sensing for four of its colleagues, allowing a single fighter to track a target, while the others use the data for a stealthy attack. TIDLS also permits multiple fighters to quickly and accurately lock onto a target's track through triangulation from several radars; or allows one fighter to jam a target while another tracks it; or allows multiple fighters to use different radar frequencies collaboratively to "burn through" jamming transmissions. TIDLS also gives the Gripen transparent access to the SAAB-Ericsson 340B Erieye "mini-AWACs" aircraft, as well as the overall ground command and control system. This system provides Sweden with an impressive defensive capability at a cost that, though still high, is less than that of comparable systems elsewhere.
TIDLS can connect up to four aircraft in a full-time two-way link. It has a range of 500 km and is highly resistant to jamming; almost the only way to jam the system is to position a jammer aircraft directly between the two communicating Gripens. Its basic modes include the ability to display the position, bearing, and speed of all four aircraft in a formation, including basic status information such as fuel and weapons state. The TIDLS is fundamentally different from broadcast-style links like Link 16. It serves fewer users but links them more closely together, exchanging much more data, and operating much closer to real time.
TIDLS information, along with radar, EW, and mapping data, appears on the central MFD. The display reflects complete sensor fusion: a target that is being tracked by multiple sources is one target on the screen. Detailed symbols distinguish between friendlies, hostiles, and unidentified targets and show who has targeted whom.
Today, Sweden is the only country that is flying with a link of this kind.
The Flygvapnet has already proven some of the tactical advantages of the link, including the ability to spread the formation over a much wider area. Visual contact between the fighters is no longer necessary, because the datalink shows the position of each aircraft. Leader and wingman roles are different: the pilot in the best position makes the attack, and the fact that he has targeted the enemy is immediately communicated to the three other aircraft.
A basic use of the datalink is "silent attack." An adversary may be aware that he is being tracked by a fighter radar that is outside missile range. He may not be aware that another, closer fighter is receiving that tracking data and is preparing for a missile launch without using its own radar. After launch, the shooter can break and escape, while the other fighter continues to pass tracking data to the missile. In tests, Gripen pilots have learned that this makes it possible to delay using the AMRAAM's active seeker until it is too late for the target to respond.
But the use of the link goes beyond this, towards what the Swedish Air Force calls "samverkan," or close-cooperation. One example is the use of the Ericsson PS-05/A radar with TIDLS. An Ericsson paper compares its application, with identical sensors and precise knowledge of the location of both platforms, to human twins: "Communication is possible without explaining everything."
"Radar-samverkan," the Ericsson paper suggests, equips the formation with a super-radar of extraordinary capabilities. The PS-05/A can operate in passive mode, as a sensitive receiver with high directional accuracy (due to its large antenna). Two PS-05/As can exchange information by datalink and locate the target by triangulation. The target's signals will often identify it as well.
The datalink results in better tracking. Usually, three plots (echoes) are needed to track a target in track-while-scan mode. The datalink allows the radars to share plots, not just tracks, so even if none of the aircraft in a formation gets enough plots on its own to track the target, they may do so collectively.
Each radar plot includes Doppler velocity, which provides the individual aircraft with range-rate data. However, this data on its own does not yield the velocity of the target. Using the TIDLS, two fighters can take simultaneous range-rate readings and thereby determine the target's track instantly, reducing the need for radar transmission.
In ECM applications, one fighter can search, while the wingman simultaneously focuses jamming on the same target, using the radar. This makes it very difficult for the target to intercept or jam the radar that is tracking him. Another anti-jamming technique is for all four radars to illuminate the same target simultaneously at different frequencies.'