# Inertial Guidance

## The Theoretical Basis For Inertial Navigation

Inertial navigation obtains its information from the same type of inertial forces one experiences riding in an automobile when turning corners at high speed, accelerating away from a stop sign, or braking. An accelerometer measures these forces continually, and this information is processed by a computer.

An inertial navigation system makes independent measurements along each of the three principal geometric axes, which is collected by a computer. The result is real-time information about velocity and distance traveled.

Inertial guidance utilizes a family of relationships from kinematics, the description of motion. The connections between the principal formulas describing acceleration, velocity, and displacement are used. Each of these three aspects of motion contains information about the other two. An inertial navigation system continuously measures acceleration along each of the three dimensions, then calculates the corresponding instantaneous velocity. This can be used to determine the total distance traveled. By measuring acceleration as a function of time, an inertial guidance system calculates instantaneous speed and location without the need to for outside reference.