TABLE OF CONTENTS The basic concepts of inertial navigation are outlined here with the aid of some simple examples.
A simple one-dimensional example of navigation involves the determination of the position of a train which is moving along a track between two locations on a perfectly flat plane. It is possible to determine the instantaneous speed of the train and the distance it has travelled from a known starting point by using measurements of its acceleration along the track. Sensors called accelerometers provide such information about their own movement. If an accelerometer is fixed in the train, it will provide information about the acceleration of the train. The time integral of the acceleration measurement provides a continuous estimate of the instantaneous speed of the train, provided its initial speed was known. A second integration yields the distance travelled with respect to a known starting point. The accelerometer together with a computer, or other suitable device capable of integration, therefore constitutes a simple one-dimensional navigation system.
In general, a navigation system is required to provide an indication of the position of a vehicle with respect to a known grid system or reference frame. For instance, it may be required to determine the location of a vehicle in terms of x and y coordinates in a Cartesian reference frame. Considering again the example of a train moving along a track, as depicted in Figure 2.1, it is now necessary to determine the position of the train with respect to the...
