AN/ASQ-213 HARM targeting system
Introduction AN/ASQ-213 HARM Targeting Systems (HTS) The '''AN/ASQ-213''' '''HARM targeting system''' is a targeting pod mounted to the right engine inlet hardpoint of an F-16 fighter jet that enables the aircraft to track the location of hostile radar systems in any weather, and identify them to allow for usage of the AGM-88 HARM or other air-to-ground weapons. It greatly assists in SEAD and DEAD operations, where surface to air missile (SAM) sites are being either directly attacked or threatened, and therefore suppressed, by aircraft carrying anti-radar missiles and other munitions. While the firing of anti-radar missiles is possible through the usage of HARMs in Harm As Sensor (HAS) mode, a HTS pod greatly reduces the workload of the pilot, increases the precision of the HARM, and allows for HARMs to be fired while pointed away from the SAM site being attacked when in Equation of Motion (EOM) mode.As an aircraft flies closer to a SAM site and is scanned by the radar for longer, the quality of the HTS pod's report of the location of the SAM site increases. This is represented by the PGM(Position Quality) number. A single F-16 is capable of attaining a PGM5 track, the lowest quality track, up to PGM2.When combined with the F-16's datalink system, a squadron is capable of triangulating the position of SAM systems with a high degree of precision, allowing for the highest quality track, PGM1.In combat, the pod displays the range, bearing, and type of threats to the aircraft in relation to itself. During flight, the pilot may adjust the area scanned by the pod as well as the frequencies scanned to optimize threat detection and ranging.
Development After the deactivation of the successful F4 Phantom which was the Wild Weasel IV, the contract for the creation of the HTS pod was awarded to Texas Instruments Corp (The defense business of which was sold to Raytheon in 1997 for $2.95 Billion USD). After the successes of the original design of the HTS pod, future upgraded variants featured vastly improved ranging speed and improved threat identification, as well as improving the frequency covered and the number of targets which could be tracked at once.
Reference *  US Air Force HARM Targeting Pod Page*  US Air Force