The Defense Department has improved the Patriot lower-tier air and missile shield, boosting the system's ability to search, discriminate and destroy tactical ballistic missiles as well as demonstrating a new capability to fend off electronic attack while hunting down enemy threats. The Director of Operational Test and Evaluation disclosed the previously unreported development in a report to Congress and the defense secretary last month , revealing the results of a developmental test of a major Patriot software upgrade called Post...