By March 2014, the MQ-1C Gray Eagle, an Army unmanned aerial system (UAS), will be able to train in the same airspace as the Boeing 747, with the help of the Army-developed Ground Based Sense and Avoid (GBSAA) system.
The GBSAA is a radar and warning system designed to allow soldiers to fly unmanned aerial systems, like the Gray Eagle, inside the National Air Space (NAS), while still meeting Federal Aviation Administration (FAA) regulations. The system monitors location and altitude of the UAS and other aircraft, detects possible collisions, and makes recommendations to UAS operators on how to avoid those collisions.
As unmanned aerial systems and the soldiers who fly them return home from theater, the Army needs a way to keep those UAS operators trained for the next battle, and they need to do that training inside the United States and inside the National Air Space, or NAS.
The FAA requires a pilot be able to "see and avoid" other aircraft flying in the same airspace. But a UAS has no pilot onboard. The Army can get around that by meeting other requirements, however. The Army can fly a UAS in the NAS with a chase aircraft following the UAS, for instance. It is also possible to fly in the NAS if a trained observer is watching the UAS. But the observer must be within one mile and 3,000 feet of the vehicle. Additionally, the Army can't fly the UAS in NAS at night.
The GBSAA was developed as an "alternate means of compliance" for the FAA's "see and avoid" requirement. The system senses other traffic in the area, using a 3D radar system, and uses algorithms to determine if there is danger of collision and how to avoid that danger. That information is provided to the UAS operator. When the FAA approves the system for use, the Army will be able to train UAS pilots any time of day.
