VOA慢速英语:Expert: High Costs Prevent Automated Airplane Tracking

navigation – n. the act, activity, or process of finding the way to get to a place when you are traveling in a ship, airplane, car, etc.

transmit – v. to send (information, sound, etc.) in the form of electrical signals to a radio, television, computer, etc.

automate – v. to run or operate something, such as a factory or system by using machines, computers, etc., instead of people to do the work

surveillance – n. the act of carefully watching someone or something