Wireless handheld portable navigation system and method for visually impaired pedestrians

• US 20050140544A1
• Filed: 06/02/2004
• Published: 06/30/2005
• Est. Priority Date: 03/20/2002
• Status: Abandoned Application

• Current Assignee: Robic LLP
• Original Assignee: Robic LLP
• Inventors: Gaudet, Manon, Laframboise, Marc, Chabot, Daniel, Hamel, Pierre
• Application Number:
  US10/858,211
• Publication Number:
  US 20050140544A1
• Time in Patent Office: Days
• US Class Current: 342/357.520
• CPC Class Codes: A61H 2003/063 with tactile perception
• CPC Class Codes: A61H 2003/065 in the form of braille
• CPC Class Codes: A61H 3/061 with electronic detecting or guiding means
• CPC Class Codes: A61H 3/068 Sticks for blind persons
• CPC Class Codes: G01C 21/20 Instruments for performing navigational calculations G01C21/24, G01C21/26 take precedence
• CPC Class Codes: G01C 21/206 specially adapted for indoor navigation
• CPC Class Codes: G01S 19/14 specially adapted for specific applications
• CPC Class Codes: G01S 19/47 the supplementary measurement being an inertial measurement, e.g. tightly coupled inertial

Abstract

This invention relates to a system for orienting and guiding visually impaired pedestrians. The system combines a Global Positioning System (GPS) receiver to a dead reckoning unit that compensates for GPS imprecision and loss of signal. The system is highly portable: it is based on a handheld portable computing platform that communicates wirelessly with a self-powered strap containing the GPS receiver and the dead reckoning unit. The system also uses wireless protocols to receive additional orientation information from a remote location server or operator accessible through the internet. Additionally, a positioning algorithm for mapping the user near a street intersection is provided.

Claims

1. A method for a portable positioning device to accurately determine the location of a user travelling near a road intersection where a plurality of road segments meet, said method comprising the steps of:

a) periodically obtaining positioning data for said user from a satellite-based positioning system;

b) mapping each of said positioning data to a mapped point on a digital road map including said road segments; and

c) when the user gets within a predetermined distance of the road intersection;

i. associating a candidate road segment from said plurality of road segments with each mapped point;

ii. assigning a weight to each of said mapped points;

iii. electing one of said candidate road segments upon the weights of all the mapped points associated therewith adding up to a predetermined value, thereby accurately locating the user on said elected road segment.

2. The method according to claim 1, wherein step a) comprises obtaining said positioning data from a satellite system.

3. The method according to claim 2, wherein said satellite system is a GPS.

4. The method according to claim 1, wherein the mapping of step b) comprises finding the closest road segment to said positioning data.

5. A method according to claim 1, wherein the weight assigned to each mapped point in substep c) ii. is proportional to its distance from the center of the intersection.