Our nation's defensive tracking methods are improving thanks to the work of a Tennessee Tech University electrical and computer engineering professor. TTU's Ali T. Alouani — along with co-inventors John E. Gray of King George, Va., and Denis Hugh McCabe of Fredericksburg, Va. — have created a method recently patented by the U.S. Navy that distributes the processing of information and measurements gathered from multiple sources at varying times to make threat assessment more accurate.
"Essentially, it is an algorithm — a series of equations — that functions as a brain, fusing and processing information that further improves defensive tracking using multiple asynchronous sensors," Alouani said. "Anytime more information can be analyzed more quickly and more accurately, better threat assessment quality will result."
The Navy currently uses the Aegis Combat System to coordinate data acquisition, interpretation and decision-making. That system functions for the Navy much like the five senses function for a person, Alouani explained, but instead of eyes and ears, radar is one type of sensor the system uses to gather such information as position, velocity and elevation of possible targets. But not all of the different Aegis-equipped weapons platforms use the same types of sensors. That, combined with the limited bandwidth of current communications technology, has made centralized information processing difficult. While there is limited data sharing across some weapons platforms, primarily cruisers and destroyers, improvements in communication and processing were needed for the multiple types of asynchronous sensors to function more efficiently system-wide.
"Contrary to synchronous sensors, asynchronous sensors provide information signals at different times. This allows for better coverage with fewer resources," Alouani said.
In order for multiple sensors to perform sequential, real-time processing, however, all the sensor nodes would have to "receive the same data, at the same time, and without delays," according to the patent. Therefore, most of the existing track fusion algorithms currently in use by the military are most effective only for synchronized tracks.
"Because the U.S. Navy sensors are distributed across wide geographical areas, the existing assumption that all the data arrive at the same time without delay is not realistic," Alouani said. "The assumption of synchronicity can lead to inconsistent assessment, but the new invention accounts for real-world constraints in target tracking while providing an optimal solution to the problem."
In addition to the use of dissimilar sensors and the limited bandwidth of communications technology, another barrier to using multiple asynchronous sensors to create a real-time scenario is the large volume of data that must be processed by the system. Because of these barriers, the result is out-of-sequence or redundant tracks that can complicate or delay military decision-making, and when it comes to threat assessment, complications and delays can be deadly.
"This becomes a difficult problem to solve for real-time applications when there is a large amount of data being distributed across the network," according to the patent. But Alouani's asynchronous multi-sensor fusion approach overcomes these barriers to create a more accurate single integrated air picture. Alouani's information filtering technique incorporates a track fusion center that combines and processes data generated from all of the single sensor platforms to create a common and more complete picture of the entire operational environment. Ideally, this common tactical picture would be displayed across all levels of the sensor nodes, to military decision-makers and shooters.
"The obvious advantages of having a more accurate picture of the environment is that it will minimize miscorrelations of threats and the creation of false tracks to increase battle-space awareness and
improve reaction time," Alouani said. "This project is proof that teaching and research can be conducted successfully at the same time, and because we are capable of performing such research here, I think it says a lot about the quality of TTU," Alouani said.