Ultrasonic position locating method and apparatus therefor
First Claim
1. A method for measuring a distance, comprising:
- a. causing an acoustic disturbance to be emitted from a first distance reference, said acoustic disturbance consisting of a plurality of individual wave cycles;
b. causing a high speed counter to be started at a counter start time, said counter start time having a fixed temporal relationship to an instant of emission of said acoustic disturbance;
c. Intercepting said acoustic disturbance at a second distance reference, and converting said acoustic disturbance into an equivalent electrical signal;
d. identifying a reference cycle of said individual wave cycles within said equivalent electrical signal, wherein said reference cycle is immediately preceded by a reference cycle of a lower amplitude;
e. identifying a reference point on said reference cycle;
f. stopping said high speed counter when said reference point on said reference wave cycle is encountered; and
g. calculating said distance based upon a reading of said high speed counter.
2 Assignments
0 Petitions
Accused Products
Abstract
A positional locating method and apparatus (10) for measuring distances by accurately determining the transit time of ultrasonic wave bursts (22) between two or more points is disclosed. Timer clocks (60), (62), (64) and (66) are started when each of the bursts (22) is triggered to be emitted from a transmission point (14), and are stopped when a highly defined point (56) in the burst (22) is received at a corresponding receiving point (32), (34), (36) and (38). The highly defined point (56) is determined by first analyzing the burst (22) to identify a particular cycle (54) within the burst (22). That particular cycle (54) is then analyzed to detect the specific point (56) within the cycle (54). Use of multiple transmitters (9312), (9314) and (9316) or receivers (932), (934) and (936) permits the dimensions using ordinary trigonometric calculations. The calculation of position within two or three physical inventive method also has sufficient resolution to permit the calculation of attitudinal data by detecting very fine positional differences in a plurality of reference points located at relatively close distances on a movable marker device (912).
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Citations
33 Claims
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1. A method for measuring a distance, comprising:
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a. causing an acoustic disturbance to be emitted from a first distance reference, said acoustic disturbance consisting of a plurality of individual wave cycles; b. causing a high speed counter to be started at a counter start time, said counter start time having a fixed temporal relationship to an instant of emission of said acoustic disturbance; c. Intercepting said acoustic disturbance at a second distance reference, and converting said acoustic disturbance into an equivalent electrical signal; d. identifying a reference cycle of said individual wave cycles within said equivalent electrical signal, wherein said reference cycle is immediately preceded by a reference cycle of a lower amplitude; e. identifying a reference point on said reference cycle; f. stopping said high speed counter when said reference point on said reference wave cycle is encountered; and g. calculating said distance based upon a reading of said high speed counter. - View Dependent Claims (2, 3, 5)
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4. A method for measuring a distance, comprising:
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a. causing an acoustic disturbance to be emitted from a first distance reference, said acoustic disturbance consisting of a plurality of individual wave cycles; b. causing a high speed counter to be started at a counter start time, said counter start time having a fixed temporal relationship to an instant of emission of said acoustic disturbance; c. intercepting said acoustic disturbance at a second distance reference, and converting said acoustic disturbance into an equivalent electrical signal; d. identifying a reference cycle of said individual wave cycles within said equivalent electrical signal; e. identifying a reference point on said reference cycle; f. stopping said high speed counter when said reference point on said reference wave cycle is encountered; and g. calculating said distance based upon a reading of said high speed counter, wherein said individual wave cycles are of unequal magnitudes, and said reference cycle is identified by the characteristic of being similar in magnitude to a corresponding cycle of a just previous acoustic disturbance, wherein; said reference cycle is a second cycle of said acoustic disturbance, and said reference cycle is identified by the characteristic of being greater in magnitude than a first cycle and lesser in magnitude than a third cycle, said first cycle and said third cycle being the first and third of said individual wave cycles of a just previous acoustic disturbance.
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6. An apparatus for locating a position of a movable marker, including:
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a plurality of transmitting means, each for transmitting an ultrasonic wave burst; a plurality of receiving means, each for receiving the ultrasonic wave burst from each of the transmitting means; reference point identification means for identifying a specific cycle within each ultrasonic wave burst and further for identifying a specific reference point within said specific cycle; timing means for measuring a propagation time of each ultrasonic wave burst between one of the transmitting means and one of the receiving means, said propagation time being time elapsed between transmission of each ultrasonic wave burst from one of the transmitting means and reception of said specific reference point on said wave burst at one of the receiving means; and distance calculating means for calculating distances between one of the transmitting means and one of the receiving means based upon said propagation time and a known speed of sound; and calculating means for performing basic trigonometric calculations to determine the position and attitude of the movable marker with respect to the apparatus using as variables the distances calculated by the distance calculating means. - View Dependent Claims (7, 8, 9, 12, 13, 14)
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10. An apparatus for locating a position of a movable marker, including:
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a plurality of distance measuring means, each of said distance measuring means including; transmitting means for transmitting an ultrasonic wave burst; receiving means for receiving the ultrasonic wave burst; reference point identification means for identifying a specific cycle within said ultrasonic wave burst and further for identifying a specific reference point within said specific cycle; timing means for measuring a propagation time of said ultrasonic wave burst between the transmitting means and the receiving means, said propagation time being time elapsed between transmission of said ultrasonic wave burst from said transmitting means and reception of said specific reference point on said wave burst at said receiving means; and distance calculating means for calculating distances between the transmitting means and the receiving means based upon said propagation time and a known speed of sound; position calculating means for performing basic trigonometric calculations to determine the position of the movable marker with respect to the apparatus using as variables the distances calculated by the distance calculating means; compensation means for compensating for variations in an extant speed of sound, said compensation means including three fixed reference points and a movable reference point, such that differences in propagation times of the ultrasonic wave burst between said movable reference point and each of said fixed reference points will provide sufficient data to calculate said extant speed of sound wherein said three fixed reference points are positioned to be colinear.
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11. An apparatus for locating a position of a movable marker, including:
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a plurality of distance measuring means, each of said distance measuring means including; transmitting means for transmitting an ultrasonic wave burst; receiving means for receiving the ultrasonic wave burst; reference point identification means for identifying a specific cycle within said ultrasonic wave burst and further for identifying a specific reference point within said specific cycle; timing means for measuring a propagation time of said ultrasonic wave burst between the transmitting means and the receiving means, said propagation time being time elapsed between transmission of said ultrasonic wave burst from said transmitting means and reception of said specific reference point on said wave burst at said receiving means; and distance calculating means for calculating distances between the transmitting means and the receiving means based upon said propagation time and a known speed of sound; position calculating means for performing basic trigonometric calculations to determine the position of the movable marker with respect to the apparatus using as variables the distances calculated by the distance calculating means; compensation means for compensating for variations in an extant speed of sound, said compensation means including three fixed reference points and a movable reference point, such that differences in propagation times of the ultrasonic wave bursts between said movable reference point and each of said fixed reference points will provide sufficient data to calculate said extant speed of sound, wherein the receiving means are located at the movable reference point, and the ultrasonic wave emitters are located at the fixed reference point.
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15. In an ultrasonic position locating device including a plurality of ultrasonic wave transmitting means, a plurality of ultrasonic wave receiving means, a plurality of counter means, each of which is started when an ultrasonic wave burst is emitted from one of the transmitting means and is stopped when the ultrasonic wave burst is received at a corresponding receiving means, and calculating means for calculating distance based upon the output of the counter means, the improvement comprising:
a fixed reference frame having three fixed reference points said fixed reference points having a known fixed physical relationship to each other, and a movable marker having thereon three marker points having a known fixed relationship to each other, the movable marker being movable in three physical dimensions in relation to the fixed reference frame, such that when all distances between each of the fixed reference points and each of the marker points is calculated the positional attitude of the movable marker is determinable in addition to the position of the movable marker relative to the fixed reference frame. - View Dependent Claims (16, 17, 18, 19, 20)
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21. An input device for a computer comprising:
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means for transmitting acoustic signals from at least three points in a first region; means for receiving said transmitted signals at least three points in a second region; and means, operably coupled to the transmitting means and the receiving means, for providing the computer a distance and attitudinal orientation between the transmitting means and the receiving means. - View Dependent Claims (22, 23, 24, 25)
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26. An input device for a computer comprising:
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stationary transducer means; movable transducer means; means for propagating signals from one of the transducer means to the other; and control means, operably coupled to the stationary and the movable transducer means, for providing the computer with a relative position and an attitude of at least one of the transducer means relative to the other, based on propagation delays of the signals. - View Dependent Claims (27, 28, 29, 30, 31, 32, 33)
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Specification