Patent ID: 6494093
Filing Date: 2002-12-17
Classification: G01C,G01P

Abstract:
A method for measuring motion of a user, comprising the steps of:(a) producing three-axis angular rate signals by an angular rate producer and three-axis acceleration signals by an acceleration producer; (b) converting said three-axis angular rate signals into digital angular increments and converting said input three-axis acceleration signals into digital velocity increments in an angular increment and velocity increment producer; (c) computing attitude and heading angle measurements using said three-axis digital angular increments and said three-axis velocity increments in an attitude and heading processor; (d) maintaining a predetermined operating temperature throughout the steps (a) to (c), wherein said predetermined operating temperature is a constant designated temperature selected between 150Â° F. and 185Â° F.; (e) performing a parameter setting at turn on by respectively initializing a first temperature constant of a first heater and a second temperature constant of a second heater to a value of 1 deg centigrade greater than a final destination temperature; (f) for each new temperature data frame from a first temperature sensor and a second temperature sensor, in an iterative fashion, adding said first temperature constant to a first temperature sensor value from said first temperature sensor and adding a first result of a first last frame value of a first heater loop to form a current first result; (g) loading said current first result into a first down counter used to form a first length of a first pulse which varies from 0 to 100%, wherein said first pulse is used to drive said first heater; (h) saving said current first result for use during a first next iteration of said first heater loop; (i) adding said second temperature constant to a second temperature sensor value from said second temperature sensor and adding a second result of a second last frame value of a second heater loop to form a current second result; (j) loading said current second result into a second down counter used to form a second length of a second pulse which varies from 0 to 100%, wherein said second pulse is used to drive said second heater; (k) saving said current second result for use during a second next iteration of said second heater loop; (l) setting said first temperature constant of said first heater loop to said final destination temperature and setting said second heater loop to off when a temperature, which is said value of 1 deg centigrade greater than said final destination temperature, is reached, as measured by said first and second temperature sensors; and (m) setting said second temperature constant of said second heater loop to said value of said second temperature sensor and setting said second heater loop on when said temperature cools to a final temperature, as measured by said first temperature sensor.