US2015117499A1PendingUtilityA1
Method of generating binary offset carrier correlation function based on partial correlation functions, apparatus for tracking binary offset carrier signal, and spread spectrum signal receiver system using the same
Assignee: UNIV SUNGKYUNKWAN RES & BUSPriority: Oct 29, 2013Filed: Oct 28, 2014Published: Apr 30, 2015
Est. expiryOct 29, 2033(~7.2 yrs left)· nominal 20-yr term from priority
H04B 2001/70706H04B 1/7085H04B 1/70752G01S 19/30H04B 2201/707H04B 1/7075
52
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Claims
Abstract
A method of generating a BOC correlation function based on partial correlation functions, an apparatus for tracking a BOC signal, and a spread spectrum signal receiver system using the same are disclosed herein. The apparatus includes a frequency offset compensation unit, a local code generation unit, a mixer, a delay lock loop (DLL), a phase lock loop (PLL), and a data extraction unit. The frequency offset compensation unit outputs a compensated received signal with respect to a received signal. The local code generation unit generates a delay-compensated local code based on a code delay value. The mixer mixes the delay-compensated local code with the frequency offset-compensated received signal. The DLL repeatedly tracks and calculates a code delay value. The PLL repeatedly calculates a carrier frequency compensation value. The data extraction unit extracts spreading data from a mixture of the delay-compensated local code and the compensated received signal.
Claims
exact text as granted — not AI-modifiedWhat is claimed is:
1 . A delay lock loop (DLL) for tracking a code delay phase value for a local code to be correlated with a received BOC-modulated signal in which N pulses successively occur in a single period T c of a spreading code chip in a spread spectrum signal receiver system, the DLL comprising:
a local signal generation unit configured to generate an early and late delayed received signal pair B(t+τ+Δ/2) and B(t+τ−Δ/2), early delayed and late delayed, respectively, based on phase delay τ and a delay value difference Δ, with respect to a received signal pulse train of a received signal B(t); early and late correlation units configured to generate N early partial correlation functions S m (τ+Δ/2) (where 0≦m≦N−1) and N late partial correlation functions S m (τ−Δ/2) by performing an auto-correlation operation on the early and late mixed signal pair B(t+τ+Δ/2) and B(t+τ−Δ/2) with respect to a total time T(0≦t≦T); an early combination unit configured to obtain an early intermediate correlation function R 0 (τ+Δ/2;a) by performing an elimination operation on an early sub-correlation function pair T 1 (τ+Δ/2;a) and T 2 (τ+Δ/2;a), obtained by combining first and last early partial correlation functions S 0 (τ+Δ/2) and S N-1 (τ+Δ/2) based on a given main peak shape parameter a, so that only a main peak is left, and to generate an early main correlation function R proposed (τ+Δ/2;a) by superposing results obtained by additionally performing an elimination operation on the early intermediate correlation function R 0 (τ+Δ/2;a) and each of the early partial correlation functions S m (τ+Δ/2); a late combination unit configured to obtain a late intermediate correlation function R 0 (τ−Δ/2;a) by performing an elimination operation on a late sub-correlation function pair T 1 (τ−Δ/2;a) and T 2 (τ−Δ/2;a), obtained by combining first and last late partial correlation functions S 0 (τ−Δ/2) and S N-1 (τ−Δ/2) based on a given main peak shape parameter a, so that only a main peak is left, and to generate a late main correlation function R proposed (τ−Δ/2;a) by superposing results obtained by additionally performing an elimination operation on the late intermediate correlation function B 0 (τ−Δ/2;a) and each of the late partial correlation functions S m (τ−Δ/2); and a numerical control oscillator (NCO) configured to determine a phase delay τ for the received signal based on a discrimination output of a discrimination function based on values of the early and late main correlation functions, and outputs the determined phase delay τ to the local signal generation unit; wherein the elimination operation is an operation related to an algebraic relation in which when real numbers x and y are xy≦0, |x|+|y|−|x−y|=0.
2 . The DLL of claim 1 , wherein the N early partial correlation functions S m (τ+Δ/2) or the N late partial correlation functions S m (τ−Δ/2), when the received signal B(t) is viewed as a sum of N partial received signals obtained by superposing an m-th (0≦m≦N−1) pulse of N pulses present within each chip period T c on the other m-th pulses, are obtained by performing an auto-correlation operation on each of the N partial received signals based on the following equation:
R
(
τ
)
=
1
PT
∫
0
T
B
(
t
)
B
(
t
+
τ
)
t
=
∑
m
=
0
N
-
1
∑
j
=
0
T
/
T
c
-
1
1
PT
∫
(
j
N
+
m
)
(
j
N
+
m
+
1
)
B
(
t
)
B
(
t
+
τ
)
t
=
∑
m
=
0
N
-
1
S
m
(
τ
)
where P is power of the received signal B(t), T is a period of the pseudo noise code, T c is a chip period, and j (0≦j≦T/T c −1) is an index indicative of each pulse of a pulse train of an m-th partial received signal.
3 . The DLL of claim 1 , wherein the early sub-correlation function pair T 1 (τ+Δ/2;a) and T 2 (τ+Δ/2;a) or the late sub-correlation function pair T 1 (τ−Δ/2;a) and T 2 (τ−Δ/2;a) is generated such that it is symmetrical with respect to a vertical axis when the sub-correlation functions overlap each other.
4 . The DLL of claim 1 , wherein the early sub-correlation function pair T 1 (τ+Δ/2;a) and T 2 (τ+Δ/2;a) or the late sub-correlation function pair T 1 (τ−Δ/2;a) and T 2 (τ−Δ/2;a) is generated based on the following equation:
{
T
1
(
τ
;
a
)
=
1
a
2
+
1
S
0
(
τ
)
-
a
1
a
2
+
1
S
N
-
1
(
τ
)
T
2
(
τ
;
a
)
=
1
a
2
+
1
S
0
(
τ
)
-
1
a
2
+
1
S
N
-
1
(
τ
)
,
5 . The DLL of claim 1 , wherein the early intermediate correlation function R 0 (τ+Δ/2;a) or the late intermediate correlation function R 0 (τ−Δ/2;a) is generated based on the following equation:
R 0 (τ; a )=| T 1 (τ; a )|+| T 2 (τ; a )|−| T 1 (τ; a )− T 2 (τ; a )|
6 . The DLL of claim 1 , wherein the early main correlation function R proposed (τ+Δ/2;a) or the late main correlation function R proposed (τ−Δ/2;a) is generated based on the following equation:
R
proposed
(
τ
;
a
)
=
∑
m
=
0
N
-
1
R
0
(
τ
;
a
)
+
S
m
(
τ
)
-
R
0
(
τ
;
a
)
-
S
m
(
τ
)
7 . The DLL of claim 6 , wherein each of the early main correlation function R proposed (τ+Δ/2;a) and the late main correlation function R proposed (τ−Δ/2;a) is generated to have a waveform having a main peak whose height is 2 and whose base width is
(
a
-
1
-
a
2
)
N
(
a
-
1
-
1
-
a
2
)
T
c
by performing an elimination operation on each of the early and late sub-correlation function pairs.
8 . The DLL of claim 1 , wherein the discrimination function is selected such that it can determine whether a main correlation function value based on the phase delay τ is located at an apex of the main peak based on the discrimination output.
9 . The DLL of claim 8 , wherein the discrimination function D(τ) is defined as the following equation:
D
(
τ
)
=
R
proposed
2
(
τ
+
Δ
2
;
a
)
-
R
proposed
2
(
τ
-
Δ
2
;
a
)
10 . The DLL of claim 9 , wherein the code delay phase value for the local code is determined to be a value of the phase delay τ when zero crossing of the discrimination function D(τ) is detected.
11 . A BOC signal tracking method for tracking a code delay phase value for a local code to be correlated with a received BOC-modulated signal in which N pulses successively occur in a single period T c of a spreading code chip in a spread spectrum signal receiver system, the method comprising:
generating an early and late delayed received signal pair B(t+τ+Δ/2) and B(t+τ−Δ/2), early delayed and late delayed, respectively, based on phase delay τ and a delay value difference Δ, with respect to a received signal pulse train of a received signal B(t); generating N early partial correlation functions S m (τ+Δ/2) (where 0≦m≦N−1) and N late partial correlation functions S m (τ−Δ/2) by performing an auto-correlation operation on the early and late mixed signal pair B(t+τ+Δ/2) and B(t+τ−Δ/2) with respect to a total time T(0≦t≦T); obtaining an early intermediate correlation function R 0 (τ+Δ/2;a) by performing an elimination operation on an early sub-correlation function pair T 1 (τ+Δ/2;a) and T 2 (τ+Δ/2;a), obtained by combining first and last early partial correlation functions S 0 (τ+Δ/2) and S N-1 (τ+Δ/2) based on a given main peak shape parameter a, so that only a main peak is left, and generating an early main correlation function R proposed (τ+Δ/2;a) by superposing results obtained by additionally performing an elimination operation on the early intermediate correlation function R 0 (τ+Δ/2;a) and each of the early partial correlation functions S m (τ+Δ/2); obtaining a late intermediate correlation function R 0 (τ−Δ/2;a) by performing an elimination operation on a late sub-correlation function pair T 1 (τ−Δ/2;a) and T 2 (τ−Δ/2;a), obtained by combining first and last late partial correlation functions S 0 (τ−Δ/2) and S N-1 (τ−Δ/2) based on a given main peak shape parameter a, so that only a main peak is left, and generating a late main correlation function R proposed (τ−Δ/2;a) by superposing results obtained by additionally performing an elimination operation on the late intermediate correlation function R 0 (τ−Δ/2;a) and each of the late partial correlation functions S m (τ−Δ/2); and determining a phase delay τ for the received signal based on a discrimination output of a discrimination function based on values of the early and late main correlation functions; wherein the elimination operation is an operation related to an algebraic relation in which when real numbers x and y are xy≦0, |x|+|y|−|x−y|=0.
12 . The BOC signal tracking method of claim 11 , wherein the N early partial correlation functions S m (τ+Δ/2) or the N late partial correlation functions S m (τ−Δ/2), when the received signal B(t) is viewed as a sum of N partial received signals obtained by superposing an m-th (0≦m≦N−1) pulse of N pulses present within each chip period T c on the other m-th pulses, are obtained by performing an auto-correlation operation on each of the N partial received signals based on the following equation:
R
(
τ
)
=
1
PT
∫
0
T
B
(
t
)
B
(
t
+
τ
)
t
=
∑
m
=
0
N
-
1
∑
j
=
0
T
/
T
c
-
1
1
PT
∫
(
j
N
+
m
)
(
j
N
+
m
+
1
)
B
(
t
)
B
(
t
+
τ
)
t
=
∑
m
=
0
N
-
1
S
m
(
τ
)
where P is power of the received signal B(t), T is a period of the pseudo noise code, T c is a chip period, and j (0≦j≦T/T c −1) is an index indicative of each pulse of a pulse train of an m-th partial received signal.
13 . The BOC signal tracking method of claim 11 , wherein the early sub-correlation function pair T 1 (τ+Δ/2;a) and T 2 (τ+Δ/2;a) or the late sub-correlation function pair T 1 (τ−Δ/2;a) and T 2 (τ−Δ/2;a) is generated such that it is symmetrical with respect to a vertical axis when the sub-correlation functions overlap each other.
14 . The BOC signal tracking method of claim 11 , wherein the early sub-correlation function pair T 1 (τ+Δ/2;a) and T 2 (τ+Δ/2;a) or the late sub-correlation function pair T 1 (τ−Δ/2;a) and T 2 (τ−Δ/2;a) is generated based on the following equation:
{
T
1
(
τ
;
a
)
=
1
a
2
+
1
S
0
(
τ
)
-
a
1
a
2
+
1
S
N
-
1
(
τ
)
T
2
(
τ
;
a
)
=
1
a
2
+
1
S
0
(
τ
)
-
1
a
2
+
1
S
N
-
1
(
τ
)
,
15 . The BOC signal tracking method of claim 11 , wherein the early intermediate correlation function R 0 (τ+Δ/2;a) or the late intermediate correlation function R 0 (τ−Δ/2;a) is generated based on the following equation:
R 0 (τ; a )=| T 1 (τ; a )|+| T 2 (τ; a )|−| T 1 (τ; a )− T 2 (τ; a )|
16 . The BOC signal tracking method of claim 11 , wherein the early main correlation function R proposed (τ+Δ/2;a) or the late main correlation function R proposed (τ−Δ/2;a) is generated based on the following equation:
R
proposed
(
τ
;
a
)
=
∑
m
=
0
N
-
1
R
0
(
τ
;
a
)
+
S
m
(
τ
)
-
R
0
(
τ
;
a
)
-
S
m
(
τ
)
17 . The BOC signal tracking method of claim 16 , wherein each of the early main correlation function R proposed (τ+Δ/2;a) and the late main correlation function R proposed (τ−Δ/2;a) is generated to have a waveform having a main peak whose height is 2 and whose base width is
(
a
-
1
-
a
2
)
N
(
a
-
1
-
1
-
a
2
)
T
c
by performing an elimination operation on each of the early and late sub-correlation function pairs.
18 . The BOC signal tracking method of claim 11 , wherein the discrimination function is selected such that it can determine whether a main correlation function value based on the phase delay τ is located at an apex of the main peak based on the discrimination output.
19 . The BOC signal tracking method of claim 18 , wherein the discrimination function D(τ) is defined as the following equation:
D
(
τ
)
=
R
proposed
2
(
τ
+
Δ
2
;
a
)
-
R
proposed
2
(
τ
-
Δ
2
;
a
)
20 . The BOC signal tracking method of claim 19 , wherein the code delay phase value for the local code is determined to be a value of the phase delay τ when zero crossing of the discrimination function D(τ) is detected.
21 . A method for generating a correlation function used to track a code delay phase value for a local code to be correlated with a received BOC-modulated signal in which N pulses successively occur in a single period T c of a spreading code chip in a spread spectrum signal receiver system, the method comprising:
generating a delayed received signal B(t+τ) based on phase delay τ with respect to a received signal pulse train of a received signal B(t); generating N partial correlation functions S m (τ) (where 0≦m≦N−1) by performing an auto-correlation operation on the received signal B(t) and the delayed received signal B(t+τ) with respect to a total time T(0≦t≦T); and obtaining an intermediate correlation function R 0 (τ;a) by performing an elimination operation on a sub-correlation function pair T 1 (τ;a) and T 2 (τ;a), obtained by combining first and last partial correlation functions S 0 (τ) and S N-1 (τ) based on a given main peak shape parameter a, so that only a main peak is left, and generating a main correlation function R proposed (τ;a) by superposing results obtained by additionally performing an elimination operation on the intermediate correlation function R 0 (τ;a) and each of the partial correlation functions S m (τ); wherein the elimination operation is an operation related to an algebraic relation in which when real numbers x and y are xy≦0, |x|+|y|−|x−y|=0.
22 . The method of claim 21 , wherein the N partial correlation functions S m (τ), when the received signal B(t) is viewed as a sum of N partial received signals obtained by superposing an m-th (0≦m≦N−1) pulse of N pulses present within each chip period T c on the other m-th pulses, are obtained by performing an auto-correlation operation on each of the N partial received signals based on the following equation:
R
(
τ
)
=
1
PT
∫
0
T
B
(
t
)
B
(
t
+
τ
)
t
=
∑
m
=
0
N
-
1
∑
j
=
0
T
/
T
c
-
1
1
PT
∫
(
j
N
+
m
)
(
j
N
+
m
+
1
)
B
(
t
)
B
(
t
+
τ
)
t
=
∑
m
=
0
N
-
1
S
m
(
τ
)
where P is power of the received signal B(t), T is a period of the pseudo noise code, T c is a chip period, and j (0≦j≦T/T c −1) is an index indicative of each pulse of a pulse train of an m-th partial received signal.
23 . The method of claim 21 , wherein the sub-correlation function pair T 1 (τ;a) and T 2 (τ;a) is generated such that a waveform in a positive range τ>0 of the first sub-correlation function T 1 (τ;a) is symmetrical to a waveform in a negative range τ<0 of the second sub-correlation function T 2 (τ;a) with respect to a vertical axis and a waveform in a negative range τ<0 of the first sub-correlation function T 1 (τ;a) is symmetrical to a waveform in a positive range τ>0 of the second sub-correlation function T 2 (τ;a) with respect to a vertical axis.
24 . The method of claim 21 , wherein the sub-correlation function pair T 1 (τ;a) and T 2 (τ;a) is generated based on the following equation:
{
T
1
(
τ
;
a
)
=
1
a
2
+
1
S
0
(
τ
)
-
a
1
a
2
+
1
S
N
-
1
(
τ
)
T
2
(
τ
;
a
)
=
1
a
2
+
1
S
0
(
τ
)
-
1
a
2
+
1
S
N
-
1
(
τ
)
,
25 . The method of claim 21 , wherein the intermediate correlation function R 0 (τ;a) is generated based on the following equation:
R 0 (τ; a )=| T 1 (τ; a )|+| T 2 (τ; a )|−| T 1 (τ; a )− T 2 (τ; a )|
26 . The method of claim 21 , wherein the main correlation function R proposed (τ;a) is generated based on the following equation:
R
proposed
(
τ
;
a
)
=
∑
m
=
0
N
-
1
R
0
(
τ
;
a
)
+
S
m
(
τ
)
-
R
0
(
τ
;
a
)
-
S
m
(
τ
)
27 . The method of claim 26 , wherein the main correlation function R proposed (τ;a) is generated to have a waveform having a main peak whose height is 2 and whose base width is
(
a
-
1
-
a
2
)
N
(
a
-
1
-
1
-
a
2
)
T
c
by superposing peaks of |R 0 (τ;a)|+|S m (τ)|−|R 0 (τ;a)−S m (τ)| each having a height of 2/N and a width of
(
a
-
1
-
a
2
)
N
(
a
-
1
-
1
-
a
2
)
T
c
with respect to a that satisfies R 0 (τ;a)>S m (τ).
28 . The method of claim 27 , wherein the main correlation function R proposed (τ;a) has a waveform obtained by subtracting a waveform of an absolute value of a sum of T 1 (τ;a) and T 2 (τ;a) from a waveform of a sum of absolute values of T 1 (τ;a) and T 2 (τ;a).
29 . An apparatus for tracking a BOC signal, comprising:
a frequency offset compensation unit configured to output a compensated received signal compensated for frequency offset of a carrier frequency based on a carrier frequency compensation value with respect to a received signal obtained by BOC-modulating predetermined data; a local code generation unit configured to generate a delay-compensated local code based on a code delay value; a mixer configured to mix the delay-compensated local code with the frequency offset-compensated received signal; a DLL configured to repeatedly track and calculate a code delay value that allows a correlation value obtained by correlating the delay-compensated local signal and the frequency offset-compensated received signal with each other is located at an apex of a main peak of a correlation function, and to provide the calculated code delay value to the local code generation unit; a phase lock loop (PLL) configured to repeatedly calculate a carrier frequency compensation value based on an auto-correlation value of a local code, based on the tracked code delay value, so that a phase error of a carrier signal can be minimized, and to provide the carrier frequency compensation value to the frequency offset compensation unit; and a data extraction unit configured to extract spreading data from a mixture of the delay-compensated local code and the compensated received signal; wherein the DLL operates to: generate a delayed received signal B(t+τ) based on phase delay τ with respect to a received signal pulse train of a received signal B(t); generate N partial correlation functions S m (τ) (where (0≦m≦N−1) by performing an auto-correlation operation on the received signal B(t) and the delayed received signal B(t+τ) with respect to a total time T(0≦t≦T); and obtain an intermediate correlation function R 0 (τ;a) by performing an elimination operation on a sub-correlation function pair T 1 (τ;a) and T 2 (τ;a), obtained by combining first and last partial correlation functions S 0 (τ) and S N-1 (τ) based on a given main peak shape parameter a, so that only a main peak is left, and generate a main correlation function R proposed (τ;a) by superposing results obtained by additionally performing an elimination operation on the intermediate correlation function R 0 (τ;a) and each of the partial correlation functions S m (τ); wherein the elimination operation is an operation related to an algebraic relation in which when real numbers x and y are xy≦0, |x|+|y|−|x−y|=0.
30 . The apparatus of claim 29 , wherein:
the received BOC signal contains satellite navigation data; and the data extraction unit operates to extract the satellite navigation data and estimate a pseudorange based on the extracted navigation data.
31 . A spread spectrum signal receiver system, comprising:
a front end unit configured to output a digital received signal obtained by BOC-modulating a space wireless signal received from an antenna; a baseband processing unit configured to acquire and track a code delay value for the output digital received signal using a DLL, to compensate for carrier frequency offset using a PLL, and to extract the contained data from a code delay-compensated local code and a frequency offset-compensated compensated received signal; and an application processing unit configured to perform a predetermined application function based on the extracted contained data; wherein the baseband processing unit operates to: generate a delayed received signal B(t+τ) based on phase delay τ with respect to a received signal pulse train of the received signal B(t); generate N partial correlation functions S m (τ) (where 0≦m≦N−1) by performing an auto-correlation operation on the received signal B(t) and the delayed received signal B(t+τ) with respect to a total time T(0≦t≦T); obtain an intermediate correlation function R 0 (τ;a) by performing an elimination operation on a sub-correlation function pair T 1 (τ;a) and T 2 (τ;a), obtained by combining first and last partial correlation functions S 0 (τ) and S N-1 (τ) based on a given main peak shape parameter a, so that only a main peak is left, and generate a main correlation function R proposed (τ;a) by superposing results obtained by additionally performing an elimination operation on the intermediate correlation function R 0 (τ;a) and each of the partial correlation functions S m (τ); and acquire and track a code delay value from phase delay τ based on the generated main correlation function; wherein the elimination operation is an operation related to an algebraic relation in which when real numbers x and y are xy≦0, |x|+|y|−|x−y|=0.
32 . The spread spectrum signal receiver system of claim 31 , wherein:
the spread spectrum signal receiver system is a satellite navigation signal receiver system; the baseband processing unit operates to extract a pseudorange from each of a plurality of satellites to a satellite navigation signal receiver system from the contained data; and the application processing unit operates to calculate coordinates of the satellite navigation signal receiver system based on the pseudoranges provided with respect to the plurality of satellites.Join the waitlist — get patent alerts
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