A sensing system, and method of operating same, can act as a highly sensitive gradiometer. A first non-magnetic element, such as a sphere, is driven at a first resonance frequency along an axis. A magnet is attached to a second non-magnetic element, such as a plate, and driven at a second resonance frequency along the axis. The first non-magnetic element and the second non-magnetic element are coupled by a force along the axis, in resonance. The gradiometer is configured to determine a gradient magnetic field acting on one or more of the first non-magnetic element and magnet based on change in at least one resonance characteristic.