US 12,730,182 B2 · Method for locating a sound event

Abstract

The invention relates to a method for locating a sound event (S) by measuring the reception times at which at least three receivers (2, 3) receive signals representative of a sound wave emitted during the sound event (S), in particular receivers (2, 3) that have a known position or are fitted with a geolocation module configured to provide the position of the receiver (2, 3), the method comprising the steps that consist in: a) determining, for each receiver (2, 3), the reception time of a signal representative of the wave emitted during the sound event (S), referred to as “sound signal”; b) calculating, for at least two pairs of receivers (2, 3), a difference in the distances between the receivers (2, 3) of the pair and the sound event (S) based on the reception times of the sound signals; and c) determining the position of the sound event (S), by trilateration, on the basis of the one or more differences in the calculated distances and the position of the receivers (2, 3) at the corresponding reception times.

A method for locating a sound event (S) by measuring the reception times at which at least four receivers receive signals representing a sound wave emitted during said sound event (S), with the position of the receivers being known or the receivers being fitted with a geolocation module configured to provide the position of the receiver, the method comprising the following steps of:

a) determining, for each receiver, the reception time of a signal, called “sound signal”, representing the wave emitted during the sound event (S);
b) computing, for at least two pairs of receivers, a difference in the distances between the receivers of said pair and the sound event (S) based on the reception times of the sound signals;
c) determining the position of the sound event (S), by trilateration, based on the one or more differences in the computed distances and on the position of the receivers at the corresponding reception times, with the position of the sound event being the intersection of three hyperbolic surfaces whose receivers are the focal points and the differences in distance to the focal points are determined based on the reception times of the sound signals, with the computation being carried out using an orthogonal x, y, z reference frame, with the focal points of the first hyperbola being located on the right of the x axis, and the focal points of the second hyperbola being located in the xy plane, with the points M(x, y, z) of the first one of these two hyperbolic surfaces verifying an equation:
x
2
/
a
2
-
(
y
2
+
z
2
)
/
b
2
=
1
using a parameter t, such that
t
=
x
/
a
-
y
/
b
therefore
:
t
*
(
x
/
a
+
y
/
b
)
=
1
+
z
2
/
b
2
therefore
⁢
x
/
a
+
y
/
b
=
(
1
+
z
2
/
b
2
)
/
t
⁢
and
x
/
a
=
1
/
2
[
(
1
+
z
2
/
b
2
)
/
t
+
t
]
y
/
b
=
1
/
2
[
(
1
+
z
2
/
b
2
)
/
t
-
t
]
the second hyperbolic surface being the result of the rotation about an axis, in a direction parallel to z and perpendicular to the xy plane, of another hyperbolic surface rotating about the x axis and having an equation in the following form:
α
⁢
x
2
+
β
⁢
y
2
+
γ
⁢
x
⁢
y
+
ε
⁢
z
2
=
1
with this equation allowing one or more values of t to be found for each z:
α
⁡
(
a
*
1
/
2
⁢
(
t
+
(
1
+
z
2
/
b
2
)
/
t
)
)
2
+
β
*
(
b
⁢
1
/
2
⁢
(
-
t
+
(
1
+
z
2
/
b
2
)
/
t
)
)
2
+
γ
⁢
ab
*
(
t
2
-
(
1
+
z
2
/
b
2
)
⁢
2
/
t
2
)
/
4
+
ε
⁢
z
2
=
1
⁢
α
(
a
*
1
/
2
⁢
(
t
2
+
(
1
+
z
2
/
b
2
)
)
2
+
β
*
(
b
⁢
1
/
2
⁢
(
-
t
2
+
(
1
+
z
2
/
b
2
)
)
)
2
+
γ
⁢
ab
*
(
t
⁢
4
-
(
1
+
z
2
/
b
2
)
)
/
4
+
ε
⁢
z
2
⁢
t
2
=
t
2
in other words:
α
(
⁠
a
*
1
/
2
⁢
(
t
⁢
4
+
(
1
+
z
2
/
b
2
)
2
+
2
*
(
1
+
z
2
/
b
2
)
*
t
2
)
+
β
*
b
⁢
1
/
2
*
(
t
⁢
4
+
(
1
+
z
2
/
b
2
)
2
-
2
*
(
1
+
z
2
/
b
2
)
*
t
2
)
+
γ
⁢
ab
*
(
t
⁢
4
-
(
1
+
z
2
/
b
2
)
)
/
4
+
ε
⁢
z
⁢
2
⁢
t
2
=
t
2
in other words:
t
⁢
4
*
(
α
⁢
a
/
2
+
β
*
b
/
2
+
γ
⁢
ab
/
4
)
+
t
2
*
(
α
⁢
a
⁡
(
1
+
z
2
/
b
2
)
-
β
⁢
b
⁡
(
1
+
z
2
/
b
2
)
+
ε
⁢
z
2
-
1
)
+
(
α
⁢
a
/
2
*
(
1
+
z
2
/
b
2
)
2
+
β
*
b
/
2
*
(
1
+
z
2
/
b
2
)
⁢
2
-
γ
⁢
ab
/
4
*
(
1
+
z
2
/
b
2
)
=
0
providing t2 as a function of z, as well as x and y as a function of z, having up to two solutions for t2;
the third hyperbolic surface being a second-order x-, y- and z-equation, which is then converted into four t-equations, with the Cartesian equation of the third hyperbolic surface generating four t-equations, the one or more solutions to which are found using digital techniques, notably by dichotomy.

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Method for locating a sound event

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Method for locating a sound event

Life of this patent

Abstract

Claims28