In a digital strapped down inertial reference system, a plurality of strapped down, force-rebalanced rate sensors is used to sense aircraft body rates, wherein each gyroscope pick-off signal is fed back to a gyro torquer in a manner to maintain the pick-off signal essentially nulled, the torquer currents thus being proportional to sensed aircraft rates. A precision digital count proportional to the effective current supplied to the torquer is achieved by using a high frequency clock to quantize a lower frequency square wave which has been pulse width modulated in accordance with the gyro pick-off signal and by means for enabling a digital counter synchronously with the state of that square wave. The same high frequency clock signal is used to derive the counter's clock frequency, the counter output being the digital equivalent of the analog square wave which corresponds to the currents supplied to the gyro torquer. Precision currents for supply to the gyro torquer in accordance with the pulse width modulated square wave are achieved by using guard bands which account for the rise and fall times of such currents and the precision turn on and turn off characteristics of VMOS transistor power switches. An automatic rate range switching and control system controlled from the precision digital count adapts the full range cabaility of the gyroscopic rate sensor to a range consistent with the precision range of the analog-to-digital conversion apparatus.