A hip protector system includes an inflatable airbag, a proximity sensor to measure a distance to a point on the ground surface, a gyro to provide spatial orientation of the waist plane of the user, an accelerometer to determine the vertical acceleration of the waist plane of the user and a micro-controller unit. The micro-controller unit calculates a height based on proximity measurement and spatial orientation, computes values of downward velocity based on a change of the height in time and based on the vertical acceleration integrated over time and correlates the downward velocities to validate a true height in time to the ground surface. The airbag is inflated to protect the user responsive to the true height.
