CORIOLIS RATE SENSOR WITH SYNCHRONOUS QUARTER CYCLE DEMODULATION

Apparatus and method for increasing the resolution of angular rate of rotation and linear acceleration of a body with respect to three orthogonal axes. Three pairs of accelerometers (10, 12; 14, 16; and 18, 20) are arranged with their sensitive axes antiparallel to each other, and each pair is vibrated back and forth along one of the orthogonal axes. The signals output from the accelerometers are processed to determine Srate and Svel for each of the rate axes as a function of the sum and differences of the signals produced by each of the accelerometers. The value of Svel for each axis is used by a microprocessor (82) to produce a signal equal to an incremental change in velocity for each axis. The incremental change in velocity is then used in conjunction with errors estimated from previous fractional portions of the dither period for each pair of accelerometers to calculate the rate of rotation of the body about each of the axes as a function fo the values for Srate. As a further aspect of the invention, the incremental change in velocity and incremental changes in angular position may be determined as a running average of previous fractional portions of the dither frequency.