This document discusses, among other things, an inertial measurement system including a device layer including a single proof-mass 3-axis accelerometer, a cap wafer bonded to a first surface of the device layer, and a via wafer bonded to a second surface of the device layer, wherein the cap wafer and the via wafer are configured to encapsulate the single proof-mass 3-axis accelerometer. The single proof-mass 3-axis accelerometer can be suspended about a single, central anchor, and can include separate x, y, and z-axis flexure bearings, wherein the x and y-axis flexure bearings are symmetrical about the single, central anchor and the z-axis flexure is not symmetrical about the single, central anchor.