By Maksim Eskin
Inertial navigation systems are used in many situations where
the use of an external reference to measure position is impractical or unreliable.
Typical inertial navigation systems used in aeronautics and marine
applications are highly advanced pieces of equipment costing thousands of
dollars. However, inexpensive accelerometers and angular rate sensors (gyros)
can be used to make a far less accurate inertial navigation unit for around
$100. Such a design is implemented. The calibration of the sensors to minimize
error is discussed. Finally, static tests are carried out to estimate the
length of time over which the system can be considered reliable. The system
is found to have an approximate position error of 0.17 m and velocity error of
0.3 m/s after one second, making it potentially useful for increasing accuracy
of a GPS system, where typical accuracies are in the 1 to 3 meter range.