06018705 is referenced by 409 patents and cites 35 patents.

The time period that a foot is in contact with the ground during a stride taken by a user, and the period that the foot is not in contact with the ground between strides taken by the user are determined by processing and analyzing the output signal of an accelerometer. The accelerometer is mounted on the user such that its acceleration sensing axis senses acceleration in a direction substantially parallel to the bottom of the user's foot. The output of the accelerometer is high-pass filtered, amplified, and fed to the input of a micro-controller, which monitors the signal for positive and negative signal spikes that are indicative, respectively, of the moment that the foot of the user leaves the ground and the moment that the foot impacts with the ground. By measuring time intervals between these positive and negative spikes, average "foot contact times" and "foot loft times" of the user may be calculated. To derive the pace of the user, the average foot contact time is multiplied by a first constant if it is less than 400 milli-seconds (ms) and is multiplied by a second constant if it is greater than 400 ms. This pace value may, in turn, be used to calculate the distance traveled by the user.

Title
Measuring foot contact time and foot loft time of a person in locomotion
Application Number
8/942802
Publication Number
6018705
Application Date
October 2, 1997
Publication Date
January 25, 2000
Inventor
Steven R Oliver
Attleboro
MA, US
Thomas P Blackadar
Natick
MA, US
Paul J Gaudet
Tewksbury
MA, US
Agent
Wolf Greenfield & Sacks P C
Assignee
Personal Electronic Devices
MA, US
IPC
G04F 10/00
G01C 22/00
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