Abstract: A system and method for determining when a vehicle safety device should be actuated includes a sensor whose analog output is filtered and then sampled to provide acceleration data. The acceleration data is integrated to obtain a value representative of vehicle velocity V. Consecutive values of the sampled data are also stored in a RAM and thereafter totaled or averaged to provide at least two acceleration values for calculating vehicle jerk and the square of vehicle acceleration. One of the acceleration values is added to the negative value of another of the acceleration values to obtain an approximation of the slope, or jerk J, of the data; and one of the acceleration values is squared to provide a squared acceleration value A.sup.2. The jerk J is then multiplied by the velocity V to obtain the velocity-jerk product, V*J, which is subsequently added to the squared acceleration value A.sup.2 to obtain a value proportional to the rate of change of power for the sensor's seismic mass.

Abstract: A system and method for triggering a vehicle safety device in response to a crash or sudden vehicle deceleration includes conversion of an analog signal generated by an acceleration sensor and representative of instantaneous vehicle acceleration to a digital value and using a ROM lookup table to determine its natural log. An autocorrelation of the log values of the acceleration data is determined and thereafter used to calculate first and second basis vector values. A safety device trigger signal is generated by a signal space discriminator when a value calculated from the first and second basis vector values exceeds a threshold value therefor.