Power aware attitude computation during rapid rotational motion

A technique for increasing the accuracy of attitude update calculations when data sample rates are low is described. The technique is based on the use of a fixed-point coordinate rotation digital computer (CORDIC) function. In addition to improved accuracy, power consumption is reduced at lower data rates. The technique is also useful for maintaining computational accuracy during high angular rate inputs. The result of an experiment employing microelectromechanical system (MEMS) gyroscopes and comparing the CORDIC-based method with Taylor series approximations is described. In the experiment, a second-order Taylor's series approximation resulted in computed errors in the Euler angle of greater than 5/spl deg/ and 15/spl deg/ at respective sample rates of 60 and 30 samples/s, while the CORDIC-based method was accurate to within 2 arcseconds. Power consumption estimates are provided for several input data rates for CORDIC-based field-programmable gate array (FPGA) and application-specific integrated circuit (ASIC) implementations.