Disclosed are an apparatus and a method for measuring the speed of a moving
body using an accelerometer. A value of earth's gravitational acceleration component
is detected from the measurements from the accelerometer and is removed from the
acceleration value. Then, the acceleration value, after removal of the earth's
gravitational acceleration component, is used to obtain the speed of the moving
body. The earth's gravitational acceleration component is detected using a movement
average at a point of time when the speed of the moving body is to be measured.
By using the magnitude of a difference between a value obtained by removing an
x-axis movement average from an x-axis measurement from the two-axis accelerometer
and another value obtained by removing a y-axis movement average from a y-axis
measurement from the two-axis accelerometer, it is possible to regulate a window
for calculating the movement average and a weight value to each of the measurements
included in the window. The present invention saves cost by reducing the number
of expensive gyroscopes in implementing a speed measuring apparatus for vehicles.
In addition, the speed measuring apparatus designed according to the present invention
is superior to that designed according to the prior art in performance and improves
the accuracy of position estimation in position estimation apparatuses for vehicles.
