The global market for command and control, communication, computers, intelligence, surveillance, and reconnaissance (C4ISR) systems is expected to pass $100 billion by 2021, growing at a combined annual growth rate (CAGR) of 4.05 percent between 2017 and 2021, according to a new market forecast from BIS Research, "Global C4ISR Systems Market, Analysis and Forecast: 2017-2021."