Device and method for determining the arrival time of a UWB signal
View Patent ↗A device and a method for determining the arrival time of a UWB signal including at least one pulse modulated at a carrier frequency. The receiver includes a frequency translation stage for translating the UWB signal to a first intermediate frequency and a second intermediate frequency. In an integration stage, the signals translated to the first intermediate frequency and to the second intermediate frequency are integrated on a time window to give a first integration result and a second integration result respectively. The phase deviation is determined between the first and second integration results and from this phase deviation, the arrival time of the UWB signal is deduced.
1. A device for determining an arrival time of a received ultra-wide band (UWB) signal comprising at least one pulse modulated at a carrier frequency, said device comprising:
at least one translation stage for translating to an intermediate frequency, the at least one translation stage comprising a quadrature mixer comprising I and Q mixing channels;
at least one integration stage connected to the at least one translation stage, for integrating signals delivered on the I and Q channels on a time window and providing integration results for each of the I and Q channels respectively; and
means for controlling said at least one translation and integration stage for:
carrying out a first frequency translation of the UWB signal to a first intermediate frequency followed by an integration of the signal thus translated on a first time window to obtain first integration results r I 1 ,r Q 1 ;
carrying out a second frequency translation of the UWB signal to a second intermediate frequency, different from the first intermediate frequency, followed by an integration of the signal thus translated on a second time window to obtain second integration results r I 2 ,r Q 2 ;
calculating means for calculating a first phase value Θ 1 from the first integration results according to
Θ
1
=
Arc
tan
(
r
Q
1
r
I
1
)
,
a second phase value Θ 2 from the second integration results according to
Θ
2
=
Arc
tan
(
r
Q
2
r
I
2
)
and deducing therefrom a phase deviation ΔΘ=Θ 2 −θ 1 , said calculating means determining the arrival time of the received UWB signal from the phase deviation thus obtained by means of a predetermined function.
2. The device according to claim 1 , wherein the first and second time windows are combined in a single window and in that the latter is chosen to contain said pulse.
3. The device according to claim 2 , wherein said arrival time, counted from the beginning of the single window, is estimated by the predetermined function of:
t
a
=
ΔΘ
2
π
(
Δ
f
2
-
Δ
f
1
)
where ΔΘ is the phase deviation, Δf 1 is the first intermediate frequency and Δf 2 is the second intermediate frequency.
4. The device according to claim 1 , wherein said UWB signal comprises a first pulse followed by a second pulse, in that the first time window is chosen to comprise the first pulse and the second time window is chosen to comprise the second pulse.
5. The device according to claim 4 , wherein said arrival time, counted from the beginning of the first time window is estimated by the predetermined function of:
t
a
=
ΔΘ
-
2
π
f
0
Δ
t
i
-
2
πΔ
f
2
δ
t
21
2
π
(
Δ
f
2
-
Δ
f
1
)
where ΔΘ is the phase deviation, f 0 is the carrier frequency, Δf 1 is the first intermediate frequency, Δf 2 is the second intermediate frequency, Δt, is the time interval separating both pulses, δt 21 =Δt i −Δt w where Δt w is the time interval separating the first and second time windows.
6. The device according to claim 4 , wherein the time interval between the first and second time windows is selected equal to the time interval between the first and second pulses, the arrival time of the UWB signal, counted from the beginning of the first time window being estimated by the predetermined function of:
t
a
=
t
a
min
+
ΔΘ
-
ΔΘ
min
ΔΘ
max
-
ΔΘ
min
Δ
T
where ΔΘ min and ΔΘ max are phase deviations obtained for a first arrival time t a max and a second arrival time t a max , respectively, and ΔT=t a max −t a min .
7. The device according to claim 1 , wherein the predetermined function is given by a calibration curve providing the phase deviation as a function of the arrival time of the signal.
8. The device for determining the arrival time of a UWB signal between a transmitter and a receiver according to claim 7 , wherein the curve is obtained via a statistics of the phase deviation values as a function of the arrival time of the signal, in the absence of synchronization of the transmitter and the receiver.
9. A device for determining an arrival time of a received ultra-wide band (UWB) signal comprising a first pulse modulated at a carrier frequency, followed by a second pulse modulated at a second carrier frequency, said device comprising:
a translation stage for translating to an intermediate frequency, the translation stage comprising a quadrature mixer comprising I and Q mixing channels;
an integration stage connected to said translation stage, for integrating signals delivered on the I and Q channels on a time window and providing integration results for each of the I and Q channels respectively; and
means for controlling the translation stage and the integration stage for:
carrying out a first frequency translation of the UWB signal at an intermediate frequency followed by an integration of the signal thus translated on a first time window to obtain first integration results r I 1 ,r Q 1 ;
carrying out a second frequency translation of the UWB signal to said intermediate frequency, followed by an integration of the signal thus translated on a second time window to obtain second integration results r I 2 ,r Q 2 ;
calculating means for calculating a first phase value Θ 1 from the first integration results according to
Θ
1
=
Arc
tan
(
r
Q
1
r
I
1
)
,
a second phase value Θ 2 from the second integration results according to
Θ
2
=
Arc
tan
(
r
Q
2
r
I
2
)
and deducing therefrom a phase deviation ΔΘ=Θ 2 −Θ 1 , said calculating means determining the arrival time of the received UWB signal from the phase deviation thus obtained via a predetermined function.
10. The device according to claim 9 , wherein the intermediate frequency is the median frequency between the first and second carrier frequencies.
11. A device for determining an arrival time of a received ultra-wide band (UWB) signal comprising at least one pulse modulated at a carrier frequency, said device comprising:
circuitry configured to
translate to an intermediate frequency on I and Q mixing channels,
integrate signals delivered on the I and Q channels on a time window and providing integration results for each of the I and Q channels respectively,
carry out a first frequency translation of the UWB signal to a first intermediate frequency followed by an integration of the signal thus translated on a first time window to obtain first integration results r I 1 ,r Q 1 ,
carry out a second frequency translation of the UWB signal to a second intermediate frequency, different from the first intermediate frequency, followed by an integration of the signal thus translated on a second time window to obtain second integration results r I 2 ,r Q 2 ;
calculate a first phase value Θ 1 from the first integration results according to
Θ
1
=
Arc
tan
(
r
Q
1
r
I
1
)
,
a second phase value Θ 2 from the second integration results according to
Θ
2
=
Arc
tan
(
r
Q
2
r
I
2
)
and deducing therefrom a phase deviation ΔΘ=Θ 2 −Θ 1 , and
determine the arrival time of the received UWB signal from the phase deviation via a predetermined function.