Position detecting system and method
First Claim
1. A position detecting system for determining the coordinates of a point of interest in a m-dimensional coordinate system, comprising:
- a) a transmitter associated with the point of interest for the transmission of a sound in the coordinate system;
b) a plurality of receivers each having a known location, the number of receivers being at least m plus two, for receiving the sound transmission;
c) analyzing means operably associated with the receivers to generate measurements relating to the distances between the transmitter and each receiver and using such measurements to eliminate the speed of sound as a necessary variable, and to identify the location of the point of interest.
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Accused Products
Abstract
A detecting system and method of determining the position of a mobile point of interest in a m dimensional coordinate system having an ultrasonic transmitter mounted on the point of interest, and a plurality of stationary ultrasonic receivers, the number being at least m plus 2. The location of the receivers are determined optimally by using a linear matrix formulation. Alternatively, the location of the receivers can be determined during installation or self-calibration of the system. The system also includes receiver controlling means for processing the received signal to generate time of flight measurements which are used to eliminate the speed of sound as a variable and to compute the location of the point of interest. The controlling means also generates phase measurements when prompted by an outside source by comparing the transmitted signal with a 40kHz pulse sync to refine the accuracy of the location of the point of interest.
84 Citations
23 Claims
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1. A position detecting system for determining the coordinates of a point of interest in a m-dimensional coordinate system, comprising:
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a) a transmitter associated with the point of interest for the transmission of a sound in the coordinate system; b) a plurality of receivers each having a known location, the number of receivers being at least m plus two, for receiving the sound transmission; c) analyzing means operably associated with the receivers to generate measurements relating to the distances between the transmitter and each receiver and using such measurements to eliminate the speed of sound as a necessary variable, and to identify the location of the point of interest. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A position detecting system for determining the coordinates of a point of interest in a m-dimensional coordinate system, comprising:
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a) a transmitter mounted to the point of interest for transmitting a sound in the coordinate system; b) a plurality of receivers, the number of receivers being at least m plus two for receiving the transmitted sound and producing a signal indicating the reception of the transmitted signal; c) strobe means operably connected to the transmitter for supplying the transmitter with a strobe to initiate the transmission of the sound; d) a plurality of controlling means equalling the number of receivers, the controlling means connected to the strobe means and respective receivers to process the signals and to generate measurements relating to a distance between the transmitter and each receiver; and e) computing means operably associated with each controlling means for using measurements of the distance between the transmitter and each receiver to eliminate speed of sound as a variable and compute a location of the point of interest. - View Dependent Claims (14, 15, 16, 17, 18)
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19. A method for determining the coordinates of a point of interest in a m-dimensional coordinate system, comprising the steps of:
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a. positioning a transmitter on the point of interest; b. transmitting a sound pulse with the transmitter; c. providing a plurality of stationary receivers, the number of receivers being m plus 2 for receiving the transmitted sound; d. generating distance measurements from time of flight measurements relating to the time between transmission of the sound and reception of the sound by respective receivers; and e. computing the location of the point of interest eliminating speed of sound as a variable using the distance measurements. - View Dependent Claims (20, 21)
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- 22. A method for determining the coordinates of a plurality of receivers in a m-dimensional coordinate system wherein the number of receivers being m plus 2, and using euation
- space="preserve" listing-type="equation">M=Aμ
where M is the measurement vector, A is the receiver location matrix denote by vectors V1, V2, V3, V4 and V5 and μ
is the unknown vector and projection on the column space of the matrix A, comprising the steps of;a. obtaining resultant vector dot product equations and variables from matrix A; b. defining values for two vectors; and c. inserting those values into nine equations and solving the nine equations numerically for the remaining three vectors. - space="preserve" listing-type="equation">M=Aμ
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23. A method for determining the coordinates of n receivers during installation and calibration of the system by:
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(a) placing the transmitter at k known locations; (b) performing a ranging operation for each location; and (c) using the following equation for each receiver location (xi, yi, zi) to determine each receivers coordinates;
##EQU8## wherein a measurement vector (t1, T2, ..., tk) represents a time of flight of the sound emitted by the transmitter and received by the ri receiver and td represents a time delay inherent in the system;
s represents the speed of sound;
(u1, v1, w1, . . . uk, vk, wk) represents the coordinates of the transmitter in three-dimensions;
vector p2 represents u2 +v2 +w2 which is a square of the coordinates of the transmitter, and vector r2 represents x2 +y2 +z2 which is a square of the coordinates of the receiver.
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Specification