August 10, 2007 Northrop Grumman has announced that it will equip its unmanned aircraft with technology that makes it safer to share airspace with piloted aircraft. Known as “Sense-and-Avoid”, these systems have been in development for more than five years.
“Sense-and-Avoid” is an element of the Northrop Grumman’s solution for the U.S. Navy's Broad Area Maritime Surveillance (BAMS) program which includes a requirement of "due regard" - the ability to ensure that the unmanned aircraft can operate safely with other aircraft when outside controlled airspace.
Northrop Grumman's BAMS offering features a maritime derivative of the proven RQ-4 Global Hawk unmanned aircraft with Navy-specific sensors and ground stations
"The challenge is that once the unmanned aircraft has detected another aircraft as a potential collision threat, the unmanned aircraft pilot has little time to respond," said Carl Johnson, vice president and Northrop Grumman's BAMS program manager. "You need a fail-safe solution to guarantee avoidance, so we have developed algorithms to assist the pilot in choosing the right manoeuvre.” This involves combining the features of radar and an electro-optical sensor which can generate visual images to provide the equivalent of human sight. "Initially, because the radar is more mature, it will be the primary sensor for collision avoidance, but electro-optical sensors will be added to meet sense-and-avoid requirements still being developed by the Federal Aviation Administration," said Johnson.
The baseline BAMS RQ-4N solution includes a pilot-in-the-loop as the cognitive maneuver decision-maker using the “Aircraft Collision Avoidance System” (ACAS) algorithm. In future these actions will become autonomous, allowing the unmanned aircraft to generate more aggressive manoeuvres to avoid close-in contacts without exceeding flight limits.
The BAMS programme will supply the U.S. Navy with a global intelligence, surveillance and reconnaissance system to protect its fleet and provide a capability to detect, track, classify, and identify maritime, littoral and land targets.