John Tsagalaki, age 15, of Oakland, Calif., for his question: I ~
HOW DOES INERTIAL GUIDANCE WORK?
I,nertial guidance is a method of navigation used to guide airplanes, rockets, submarines and other vehicles.
Guidance information is provided by a device called the inertial navigator. The %. equipment is made of a gyroscope, or spinning toplike wheels, that indicate direction, and accelerometers, or devices that measure changes in speed and direction.
An electronic computer then uses the information provided by the inertial nasvigator to calculate the vehicle's position and to guide it on its course.
Unlike other methods of navigation, inertial guidance does not rely on observations of land or the stars, on radio or radar signals, or on any other information from outside the vehicle. All of the guidance information is provided by the inertial navigator.
The inertial navigator automatically measures changes in the vehicle's motion and sends the information to the computer. The computer then calculates the effect of all the changes and keeps track of how far and in what direction the vehicle has moved from its starting point.
The inertial navigator measures how far a vehicle has traveled by recording the changes in the position of a vertical line. This line indicates the direction to the center of the earth.
Vertical lines from any two points on the earth meet at the center of the earth. The angle between the lines indicates the distance between the points. Each minute, or 1/16th of a degree, of angle indicates a surface distance of one nautical mile.
The distance from New York City to London is 3,006 nautical miles. Therefore, a pilot flying from London to New York City knows he has gone far enough when the vertical line of his inertial navigator has moved through an angle of 3,006 minutes.
The principles of inertial guidance have been known to scientists since the early 1900s when gyroscopes were first understood.
An inertial guidance system was used by German scientists to guide their V 2 rockets to England during World War II.
During the early 1950s, a scientist named Charles Draper headed a team at the Massachusetts Institute of Technology in building the first highly accurate inertial guidance system. Then in 1953 Draper made the first long distance airplane flight .guided by an inertial navigator.
In 1958, inertial navigators were used to guide the United States submarines Nautilus and Skate under the Arctic ice to the North Pole.
Inertial guidance systems were used on the Apollo spacecrafts that took men to the moon. And they are also required now on all United States commercial overseas flights.