Mercury Computer Systems Inc. of Chelmsford, Mass., has been selected by BAE Systems of Rockville, Md., to provide a synthetic vision display to land helicopters in rotorcraftbrownout conditions. It is the second contract awarded to the company to provide the VistaNav synthetic vision technology to help pilots safely land a helicopter even when dust clouds result in zero-visibility conditions. The system will generate a 3-D terrain map drawn from databases and from sensor readings.