Method of personal navigation using stride vectoring

Abstract

A method of error compensation for an inertial measurement unit is provided. The method comprises providing a first object including an inertial measurement unit, providing a second object proximal to the first object, and determining an initial position and orientation of the first object. A motion update is triggered for the inertial measurement unit when the second object is stationary with respect to a ground surface. At least one position vector is measured between the first object and the second object when the first object is in motion and the second object is stationary. A distance, direction, and orientation of the second object with respect to the first object are calculated using the at least one position vector. An error correction is then determined for the inertial measurement unit from the calculated distance, direction, and orientation of the second object with respect to the first object.

What is claimed is: 
     
         1 . A method for personal navigation, comprising:
 measuring a first position vector from a first object to a second object in a coordinate reference frame of the first object;   measuring a second position vector from the second object to the first object in a coordinate reference frame of the second object;   calculating a distance, direction, and orientation of the second object with respect to the first object using the first and second position vectors; and   determining a corrected path for navigation from the calculated distance, direction, and orientation of the second object with respect to the first object.   
     
     
         2 . The method of  claim 1 , wherein the first and second objects comprise footwear. 
     
     
         3 . The method of  claim 1 , wherein the first and second objects comprise robot feet. 
     
     
         4 . The method of  claim 1 , wherein a distance between the first and second objects is provided by a magnitude of each of the first and second position vectors. 
     
     
         5 . The method of  claim 1 , wherein the first position vector provides a direction of the second object in the coordinate reference frame of the first object. 
     
     
         6 . The method of  claim 5 , wherein the second position vector provides a direction of the first object in the coordinate frame of the second object. 
     
     
         7 . The method of  claim 6 , wherein the directions of the first and second objects are used to determine the orientation and a rotation of the second object with respect to the first object. 
     
     
         8 . The method of  claim 1 , wherein the first and second position vectors are measured substantially simultaneously. 
     
     
         9 . The method of  claim 1 , further comprising using an inertial measurement unit to aid in the correction of position, heading, and distance errors while the first object is in motion. 
     
     
         10 . A system for personal navigation, comprising:
 a processor;   an inertial measurement unit operatively coupled to the processor; and   a non-transistory computer readable medium comprising instructions executable by the processor to perform a method comprising:
 measuring a first position vector from a first object to a second object in a coordinate reference frame of the first object; 
 measuring a second position vector from the second object to the first object in a coordinate reference frame of the second object; 
 calculating a distance, direction, and orientation of the second object with respect to the first object using the first and second position vectors; and 
 determining a corrected path for navigation from the calculated distance, direction, and orientation of the second object with respect to the first object; 
   wherein the inertial measurement unit aids in the correction of position, heading, and distance errors while the first object is in motion.   
     
     
         11 . The system of  claim 10 , wherein the first and second objects comprise footwear. 
     
     
         12 . The system of  claim 10 , wherein the first and second objects comprise robot feet. 
     
     
         13 . The system of  claim 10 , wherein a distance between the first and second objects is provided by a magnitude of each of the first and second position vectors. 
     
     
         14 . The system of  claim 10 , wherein the first position vector provides a direction of the second object in the coordinate reference frame of the first object. 
     
     
         15 . The system of  claim 14 , wherein the second position vector provides a direction of the first object in the coordinate frame of the second object. 
     
     
         16 . The system of  claim 15 , wherein the directions of the first and second objects are used to determine the orientation and a rotation of the second object with respect to the first object. 
     
     
         17 . The system of  claim 10 , wherein the first and second position vectors are measured substantially simultaneously. 
     
     
         18 . A computer program product, comprising:
 a non-transistory computer readable medium comprising instructions executable by a processor to perform a method comprising:
 measuring a first position vector from a first object to a second object in a coordinate reference frame of the first object; 
 measuring a second position vector from the second object to the first object in a coordinate reference frame of the second object; 
 calculating a distance, direction, and orientation of the second object with respect to the first object using the first and second position vectors; and 
 determining a corrected path for navigation from the calculated distance, direction, and orientation of the second object with respect to the first object.