Method and apparatus for sensing a vehicle crash in real time using frequency domain analysis

An apparatus for controlling actuation of a passenger restraint system in a vehicle, said apparatus comprising:

• sensing means for providing, upon the occurrence of a vehicle crash condition, a time domain vibratory electric signal having frequency components indicative of such vehicle crash condition;
• anti-alias filter means connected to said sensing means for filtering all frequency components from said vibratory electric signal greater than three kilo-hertz;
• means for transforming said filtered time domain vibratory electric signal into a frequency domain signal;
• means for correlating said frequency domain signal and for providing a signal indicative of the degree of correlation;
• and
• means for actuating the passenger restraint system when said correlation signal indicates a particular type of vehicle crash is occurring.

An apparatus for controlling actuation of a passenger restraint system in a vehicle, said apparatus comprising:

• sensing mans for providing, upon the occurrence of a vehicle crash condition, a time domain vibratory electric signal having frequency components indicative of such vehicle crash condition;
• anti-alias filer means connected to said sensing means for filtering all frequency components from said vibratory electric signal greater than three kilo-hertz;
• analog to digital converter for converting said filtered vibratory electric signal into a digital signal;
• first memory means connected to said analog to digital converter means for storing digital values of said vibratory electric signal sampled at different time periods;
• digital transform processor connected to said first memory means for converting said digital time domain vibratory electric signal into a frequency domain signal;
• means for correlating said frequency domain signals from said different time periods and for providing a signal indicative of the degree of correlation;
• and
• means for actuating the passenger restraint system when said correlation signal indicates a particular type of vehicle crash is occurring.

A method for controlling actuation of a passenger restraint system in a vehicle, said method comprising the steps of:

• providing, upon the occurrence of a vehicle crash condition, a time domain vibratory electric signal having frequency components indicative of such vehicle crash condition;
• transforming said time domain vibratory electric signal into a frequency domain signal;
• correlating said frequency domain signal and providing a signal indicative of the degree of correlation;
• and
• actuating the passenger restraint system when said correlation signal indicates a particular type of vehicle crash is occurring.