Active protection system

An apparatus comprising:

• a sensor which outputs an acceleration signal in relation to an acceleration state of a device;
• and
• first means for configuring the device in relation to the acceleration signal and a configuration control input indicative of a selected operational environment in which the device is operated, wherein the first means selectively filters the acceleration signal and selectively applies a threshold to said filtered acceleration signal.

A method comprising:

• providing a plurality of acceleration signal axial components in relation to an acceleration state of a device;
• and
• detecting a free fall state of the device in relation to respective changes in phase of at least two of said acceleration signal axial components, the detecting step comprising generating a composite acceleration signal from said plurality of acceleration signal axial components, and detecting the free fall state in relation to a magnitude of the composite acceleration signal when the magnitude of the composite acceleration signal is determined to be near 1 g, a first one of the plurality of acceleration signal axial components crosses a threshold T in a first polarity direction, and a second one of the plurality of acceleration signal axial components crosses the threshold T in a second opposite polarity direction.