Method and system for vehicle speed estimation

A method comprising:

• measuring, by one or more motion sensors of a mobile phone disposed within a vehicle during a drive, motion measurements of the mobile phone within a first time period of the drive;
• detecting, based on the motion measurements, a crash event during the first time period;
• measuring, by an accelerometer of the mobile phone, a first set of measurements in a time domain indicating acceleration forces applied to the mobile phone within a second time period after the first time period;
• transforming the first set of measurements into a frequency domain;
• executing a digital bandpass filter implemented in hardware or software on the first set of measurements in the frequency domain to produce a second set of the measurements that excludes high frequency measurements from the first set of measurements caused by non-vehicular forces;
• analyzing the second set of the measurements to identify contiguous subsets of measurements in the second set of the measurements;
• resampling each contiguous subset of measurements at one or more predefined frequencies to extract corresponding sets of features for each contiguous subset of measurements;
• analyzing each set of the features to determine whether the vehicle stopped after the crash event;
• and
• generating a vehicle crash prediction for the crash event based on the motion measurements and whether the vehicle stopped after the crash event.

A mobile device comprising:

• one or more processors;
• one or more sensors, comprising an accelerometer;
• and
• a non-transitory computer-readable medium storing instructions, that when executed by the one or more processors, cause the one or more processors to perform operations including:
• measuring, by the one or more sensors, and while the mobile device is disposed within a vehicle during a drive, motion measurements of the mobile device within a first time period of the drive;
• detecting, based on the motion measurements, a crash event during the first time period;
• measuring, by the accelerometer, a first set of measurements in a time domain indicating acceleration forces applied to the mobile device within a second time period after the first time period;
• transforming the first set of measurements into a frequency domain;
• executing a digital bandpass filter implemented in hardware or software on the first set of measurements in the frequency domain to produce a second set of measurements that excludes high frequency measurements from the first set of measurements caused by non-vehicular forces;
• analyzing the second set of measurements to identify contiguous subsets of measurements in the second set of measurements;
• resampling each contiguous subset of measurements at one or more predefined frequencies to extract corresponding sets of features for each contiguous subset of measurements;
• analyzing each set of the features to determine whether the vehicle stopped after the crash event;
• and
• generating a vehicle crash prediction for the crash event based on the motion measurements and whether the vehicle stopped after the crash event.

A computer-program product tangibly embodied in a non-transitory machine-readable storage medium and comprising instructions that, when executed by one or more processors, cause the one or more processors to perform operations comprising:

• measuring, using one or more motion sensors of a mobile phone disposed within a vehicle during a drive, motion measurements of the mobile phone within a first time period of the drive;
• detecting, based on the motion measurements, a crash event during the first time period;
• measuring, using an accelerometer of the mobile phone, a first set of measurements in a time domain indicating acceleration forces applied to the mobile phone within a second time period after the first time period;
• transforming the first set of measurements into a frequency domain;
• executing a digital bandpass filter implemented in hardware or software on the first set of measurements in the frequency domain to produce a second set of the measurements that excludes high frequency measurements from the first set of measurements caused by non-vehicular forces;
• analyzing the second set of the measurements to identify contiguous subsets of measurements in the second set of the measurements;
• resampling each contiguous subset of measurements at one or more predefined frequencies to extract corresponding sets of features for each contiguous subset of measurements;
• analyzing each set of the features to determine whether the vehicle stopped after the crash event;
• and
• generating a vehicle crash prediction for the crash event based on the motion measurements and whether the vehicle stopped after the crash event.