Method and system of three-dimensional positional finding

• US 7,423,580 B2
• Filed: 03/14/2006
• Issued: 09/09/2008
• Est. Priority Date: 03/14/2005
• Status: Active Grant

• Current Assignee: Qualcomm Technologies Incorporated (Qualcomm, Inc.)
• Original Assignee: InvisiTrack, Inc.
• Inventors: Mikhienko, Evgenii, Markhovsky, Russ, Vityaev, Evgenii
• Primary Examiner(s): Sotomayor; John B
• Application Number:
  US11/375,161
• Publication Number:
  US 20060256001A1
• Time in Patent Office: 910 Days
• Field of Search: 342/42, 342/46, 342/47, 342/50, 342/52, 342 56- 58, 342/118, 342/125, 342/126, 342/146, 340/539.13, 340/573.4, 340/572.1, 340/539.32, 455/456.1, 455/550.1
• US Class Current: 342/126
• CPC Class Codes: G01S 13/74 Systems using reradiation of radio waves, e.g. secondary radar systems; Analogous systems
• CPC Class Codes: G01S 13/87 Combinations of radar systems, e.g. primary radar and secondary radar

Abstract

The present invention is an RF system and methods for finding a target T in three dimensional space configured to have a transponder disposed on the target T, a monitoring unit configured as a transceiver for determining or monitoring the location of the target T and an RF wireless communication system configured with a processor to repeatedly determine position, communication and other values between the transponder and monitoring unit and so as to generate a measured distance between units in three dimensional space by determining the measured distance of the target T by a spherical virtual triangulation relationship when successive values of said position information has a predetermined logical relationship relative to said previous values between said monitoring unit and transponder and/or slave unit disposed on the target T.

Claims

1. An RF system for finding a target T in three dimensional space,

comprising:

a slave unit disposed on the target T, said slave unit configured as a transponder;

a monitoring unit configured as a transceiver for monitoring the location of the target T;

a wireless communication system, said wireless communication system operating on a Radio Frequency (RF) bandwidth configured to allow communication between said slave and monitoring units, said monitoring unit configured to transmit a ranging signal to said slave unit, said slave unit responding to said ranging signal by transmitting a reply ranging signal, said wireless communication system further comprising;

a processor for determining position information of the target T, said processor in communication with an antenna, said processor being configured to repeatedly determine values for said position information from;

means for determining a transmission interval between said monitoring unit and said slave unit, said transmission interval being an elapsed time between transmitting said ranging signal and receiving said reply ranging signal,

means for determining a calibration interval between each of said monitoring unit and slave unit said calibration interval being a time interval of a period to normalize the circuitry of said monitoring and slave units, and

means for determining an antenna propagation interval of said units, said antenna propagation interval being an elapsed time of a signal measured as it passes through said antenna of said monitoring and slave units,

and

means for generating a measured distance between units in three dimensional space, said distance generating means determining said measured distance of the target T by a spherical virtual triangulation relationship when successive values of said position information has a predetermined logical relationship relative to said previous values between said monitoring unit and slave unit.

2. The system according to claim 1, wherein said processor configured to determine said spherical virtual triangulation relationship based on said position information values from at least three points P₁, P₂ and P₃ determined for said target T respective of said monitoring unit, said target T is located utilizing the point of intersection of at least three circles based on values of said position information relating to said points P₁, P₂ and P₃, whereby said points P₁, P₂ and P₃ have circles with radii R₁, R₂ and R₃ respective of said monitoring unit to said target T.

3. The system according to claim 2, wherein said processor is configured to determine said spherical virtual triangulation relationship based on measuring the value of each of said points P₁, P₂ and P₃ not in a straight line relative to said monitoring unit to reduce ambiguity, each measurement of the value of said radii R₁, R₂ and or R₃ to pinpoint the target T utilizing a position of said monitoring unit.

4. A method for finding a target in three dimensional space, comprising the steps of:

determining three spheres between successive readings between one of a transponder disposed on the target T and a transceiver each operating using radio frequency (RF), said spheres determined by successive readings each having centers that do not lie on one straight line;

numbering three separate points of an intersection of said spheres as equal either to zero or one, or two; and

calculating a position of the target T from the information of said number of points.