Airborne Radiation Thermometer 
Automatic Range Tracking 
Adaptive Runtime Technology 
Additional Reference Transmission 
Additive Reference Transmission 
Admissible Rank Test 
Advanced Reactor Technology 
Advanced Recording Technology 
Advanced Refractory Technologies, Inc. 
Advanced Research and Technology 
Aircraft Radio Technician 
Aircraft Reactor Test 
Alarm Reporting Telephone 
Applicative Real-Time 
Applied RISC Technologies 
Army Research Task 
Artificial Resynthesis Technology 
Artillery 
Artists' Rights and Theft 
Asphalt Residuum Treating 
Automated Request Transmission 
Automatic Range Tracker 
Autonomous Robotics Technology 
Average Retrieval Time 
Avionics Research Testbed 
American Refrigerator Transit 
Artern, Thüringen