Archive for April, 2008
The present invention in the field of Inertial reference systems for use on moving vehicles and more specifically relates to a short-term strapdown inertial attitude and heading reference system which is assisted by updating inputs supplied by auxiliary instruments in the vehicle is an Attitude and Heading Reference System (AHRS).
The AHRS calculates orientation from angular rate gyro data and augments these with accelerometers (inclinometer) data. Augmentation of the heading is normally done by fluxgate magnetometer or GPS. Because the orientation is augmented, this system has no restrictions on measuring time, but the operating system dynamic is an importing aspect. Before deciding on an acceptable solution, typical dynamics should be measured and depending on the results, the correct augmentation sensor chosen. Furthermore, typical sensor measurements are indispensable for choosing the correct control algorithm setup.
AHRS is not an inertial navigation system, although it resembles an inertial navigation system in some ways. The chief differences are that the device is intended to supply a short-term inertial reference rather than a long-term reference and that the present invention provides, in addition to the position of the vehicle relative to the earth, a number of other variables including the attitude of the vehicle and various other dynamic variables.