Systems such as the AN/SYS-2, now entering limited use aboard missile ships, develop a single track file based on the outputs of several radars. When radars are employed with different scan rates, a separate external timing reference must be employed, which becomes the scan rate for the IADT and the synthetic video display. Track updating and smoothing occur as previously described, except updates are considered relative to narrow sectors of the search volume -- typically a few degrees in width. System software updates tracks a few sectors behind the azimuth position of the synthetic scan. Observations are accepted from the radar having the oldest unprocessed position data sector by sector as the synthetic scan passes. This provides the first available position report, no matter which radar produced it. Thus, position reports are used as they occurred in real time, and no position report is accepted out of order. IADT reduces loss of data due to individual radar propagation and lobing characteristics while allowing quality weighting of data relative to it source. IADT systems can accept the output of TWS or non-TWS radars as well as that derived from IFF transponders.The Model 4.0 Combat Direction System software programs for the FFG-7 class Guided Missile Frigate are hosted in either AN/UYK-7 or AN/UYK-43 computers. The software interfaces digitally with other components of the Combat System, including the Mk92 Weapons System, Harpoon, AN/SYS-2 Integrated Automatic Detection and Tracking System, AN/SLQ32 Electronic Warfare System and AN/SQQ-89 Anti-Submarine Warfare System.