Proposed digital, auto ranging, self calibrating inertial sensor

A novel means of measuring inertial force is proposed which converts the spatial displacement measurement of a conventional mass-on-a-spring accelerometer to a time interval measurement by harmonically oscillating the mass-on-a-spring and creating digital triggering events when the mass passes known displacement points. By curve fitting the measured time intervals into the sinusoidal nature of the harmonic oscillator, it is possible to measure acceleration without the need of adjustable parameters (such as bias and scale factor) derived by calibration. Being a function of the accuracy of the time interval measurement, the device sensitivity varies with resonant frequency, clock resolution, and oscillation amplitude. The resonant frequency of the harmonic oscillation and the oscillation amplitude can be adjusted in real time to optimize performance for a specific dynamic range.