1. A delay locked loop (DLL), comprising:
a local signal generation unit configured to generate an early and late delayed signal pair B(t+\u03c4+\u03942) and B(t+\u03c4\u2212\u03942), early and late delayed signals, respectively, based on phase delay \u03c4 and a delay value difference \u0394, with respect to a signal pulse train of a TMBOC (Time-Multiplexed Binarly Offset Carrier) (6,1,433)-modulated received signal B(t);
early and late autocorrelation units configured to generate 12 early partial correlation functions {Pj(\u03c4+\u03942}j=011 and 12 late partial correlation functions {Pj(\u03c4\u2212\u03942}j=011 by performing autocorrelation operations of the early and late delayed signal pair with respect to a total time T(0\u2266t\u2266T);
an early sub-correlation function generation unit configured to generate an early sub-correlation function R0(\u03c4+\u03c42) by performing an elimination operation between sixth and seventh early partial correlation functions P5(\u03c4+\u03942) and P6(\u03c4+\u03942) , and a late sub-correlation function generation unit configured to generate a late sub-correlation function R0(\u03c4\u2212\u03942) by performing an elimination operation between sixth and seventh late partial correlation functions P5(\u03c4\u2212\u03942) and P6(\u03c4\u2212\u03942);
an early main correlation function combination unit configured to generate an early main correlation function Rproposed(\u03c4+\u03942) by summing results obtained by performing an elimination operation between each of remaining 10 early partial correlation functions {Pj(\u03c4+\u03942}j=0,j\u22605,611, excluding the sixth and seventh early partial correlation functions P5(\u03c4+\u03942) and P6(\u03c4+\u03942) from the 12 early partial correlation functions {Pj(\u03c4+\u03942}j=011, and the early sub-correlation function R0(\u03c4+\u03942);
a late main correlation function combination unit configured to generate a late main correlation function Rproposed(\u03c4\u2212\u03942) by summing results obtained by performing the elimination operation between each of remaining 10 late partial correlation functions {Pj(\u03c4\u2212\u03942}j=0,j\u22605,611, excluding the sixth and seventh late partial correlation functions P5(\u03c4\u2212\u03942) and P6(\u03c4\u2212\u03942) from the 12 late partial correlation functions {Pj(\u03c4\u2212\u03942}j=011, and the late sub-correlation function R0(\u03c4\u2212\u03942); and
a numerical control oscillator (NCO) configured to determine a phase delay \u03c4 of a delayed signal for the received signal based on a discrimination output based on values of the early and late main correlation functions, and to output the determined phase delay \u03c4 to the local signal generation unit;
wherein the elimination operation is an operation satisfying algebraic relations in which |A|+|B|\u2212|A \u2212B|=0 in response to real numbers A and B being AB\u22660 and |A|+|B|\u2212|A\u2212B|>0 in response to the real numbers A and B being AB>0.
2. The DLL of claim 1, wherein the early partial correlation functions {Pj(\u03c4+\u03942}j=011, and the late partial correlation functions {Pj(\u03c4\u2212\u03942}j=011 are based on the following equation:
R
\u2061
(
\u03c4
)
=
\u2062
1
PT
\u2062
\u222b
0
T
\u2062
B
\u2061
(
t
)
\u2062
B
\u2061
(
t
+
\u03c4
)
\u2062
\u2146
t
=
\u2062
\u2211
y
=
0
11
\u2062
\u2211
i
=
–
\u221e
\u221e
\u2062
1
T
\u2062
P
\u2062
\u222b
0
T
\u2062
B
\u2061
(
t
)
\u2062
p
i
\u2062
r
T
C
\u2061
(
t
+
\u03c4
–
iT
c
)
\u2062
s
i
,
j
\u2061
(
t
+
\u03c4
)
\u2062
\u2146
t
=
\u2062
\u2211
j
=
0
11
\u2062
P
j
\u2061
(
\u03c4
)
where P is power of the TMBOC(Time-Multiplexed Binary Offset Carrier)\u2014modulated signal, pi\u03b5{\u22121, 1} is an i\u2212th chip of a code having a period T, Tc is a period of a PRN code chip, rTc(t) is a unit square wave present in 0, Tc, and si,j(t) is waveforms of 12 successive units that are present in a single PRN code chip of the TMBOC modulated signal and have a period of Tc12.
3. The DLL of claim 1, wherein the early sub-correlation function R0(\u03c4+\u03942) or late sub-correlation function R0(\u03c4\u2212\u03942) are generated based on the following equation:
R0(\u03c4)=|P5(\u03c4)|+|P6(\u03c4)\u2212P5(\u03c4)\u2212P6(\u03c4)|.
4. The DLL of claim 1, wherein:
the early main correlation function combination unit generates an early main correlation function Rproposed(\u03c4+\u03942) by summing results obtained by performing an elimination operation between each of the early partial correlation functions {Pj(\u03c4+\u03942}j=011 and the early sub-correlation function R0(\u03c4+\u03942); and
the late main correlation function combination unit generates a late main correlation function Rproposed(\u03c4\u2212\u03942) by summing results obtained by performing an elimination operation between each of the late partial correlation functions {Pj(\u03c4\u2212\u03942}j=011 and the late sub-correlation function R0(\u03c4\u2212\u03942).
5. The DLL of claim 1, wherein discrimination function is defined by the following equation:
D
\u2061
(
\u03c4
)
=
R
proposed
2
\u2061
(
\u03c4
+
\u0394
2
)
–
R
proposed
2
\u2061
(
\u03c4
–
\u0394
2
)
.
6. A method of tracking a TMBOC(Time-Multiplexed Binary Offset Carrier) (6,1,433) signal, comprising:
generating an early and late delayed signal pair B(t+\u03c4+\u03942) and B(t+\u03c4\u2212\u03942), early and late delayed signals, respectively, based on a phase delay \u03c4 and a delay value difference \u0394, with respect to a signal pulse train of a TMBOC(6,1,433)-modulated received signal B(t);
generating 12 early partial correlation functions {Pj(\u03c4+\u03942}j=011 and 12 late partial correlation functions {Pj(\u03c4\u2212\u03942}j=011 by performing autocorrelation operations of the early and late delayed signal pair with respect to a total time T(0\u2266t\u2266T);
generating an early sub-correlation function R0(\u03c4+\u03942) by performing an elimination operation between sixth and seventh early partial correlation functions P5(\u03c4+\u03942) and P6(\u03c4+\u03942), and generating a late sub-correlation function R0(\u03c4\u2212\u03942) by performing the elimination operation between sixth and seventh late partial correlation functions P5(\u03c4\u2212\u03942) and P6(\u03c4\u2212\u03942);
generating an early main correlation function Rproposed(\u03c4+\u03942) by summing results obtained by performing the elimination operation between each of remaining 10 early partial correlation functions {Pj(\u03c4+\u03942}j=0,j\u22605,611, excluding the sixth and seventh early partial correlation functions P5(\u03c4=\u03942) and P6 (\u03c4+\u03942) from the 12 early partial correlation functions {Pj(\u03c4+\u03942}j=011, and the early sub-correlation function R0(\u03c4+\u03942), and generating a late main correlation function Rproposed(\u03c4\u2212\u03942) by summing results obtained by performing the elimination operation between each of remaining 10 late partial correlation functions {Pj(\u03c4\u2212\u03942}j=0,j\u22605,611, excluding the sixth and seventh late partial correlation functions P5(\u03c4\u2212\u03942) and P6(\u03c4\u2212\u03942) from the 12 late partial correlation functions {Pj(\u03c4\u2212\u03942}j=011, and the late sub-correlation function R0(\u03c4\u2212\u03942); and
determining a phase delay \u03c4 of a delayed signal for the received signal based on a discrimination output based on values of the early and late main correlation functions;
wherein the elimination operation is an operation satisfying algebraic relations in which |A|+|B|\u2212|A\u2212B|=0 in response to real numbers A and B being AB\u22660 and |A|+|B|\u2212|A\u2212B|>0 in response to the real numbers A and B being AB>0 .
7. A method of generating a correlation function of a TMBOC(Time-Multiplexed Binary Offset Carrier)(6,1,433) signal, comprising:
generating a signal B(t+\u03c4) delayed based on a phase delay \u03c4 with respect to a signal pulse train of a TMBOC(6,1,433)-modulated received signal B(t);
generating partial correlation functions {Pj(\u03c4)}j=011 by performing an autocorrelation operation of the received signal B(t) and the delayed signal B(t+\u03c4) with respect to a total time T(0\u2266t\u2266T);
generating a sub-correlation function R0(\u03c4) by performing an elimination operation of sixth and seventh partial correlation functions P5 (\u03c4) and P6 (\u03c4); and
generating a main correlation function Rproposed (\u03c4) by summing results obtained by performing the elimination operation between each of remaining 10 partial correlation functions {Pj(\u03c4}j=0,j\u22605,611, excluding the sixth and seventh early partial correlation functions P5(\u03c4) and P6(\u03c4) from the 12 partial correlation functions {Pj(\u03c4}j=011, and the sub-correlation function R0(\u03c4);
wherein the elimination operation is an operation satisfying algebraic relations in which |A|+|B|\u2212|A\u2212B|=0 in response to real numbers A and B being AB\u22660 and |A|+|B|\u2212|A\u2212B|>0 in response to the real numbers A and B being AB>0.
8. The method of claim 7, wherein generating the main correlation function Rproposed(\u03c4) comprises generating the main correlation function Rproposed(\u03c4) by summing results obtained by performing the elimination operation between each of the partial correlation functions {Pj(\u03c4}j=011 and the sub-correlation function R0(\u03c4).
9. An apparatus for tracking a TMBOC(Time-Multiplexed Binary Offset Carrier) 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 TMBOC(6,1,433)-modulated received signal;
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 (delay locked loop) configured to repeatedly track and calculate the 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 to be 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 autocorrelation value of a local code, based on the code delay value track by the DLL, so that a phase error of a carrier signal is 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:
acquire a main correlation function by summing results that are obtained by performing an elimination operation between a sub-correlation function, generated through the elimination operation of sixth and seventh partial correlation functions of partial correlation functions constituting an autocorrelation function obtained when the TMBOC(6,1,433)-modulated received signal is construed as a pulse train composed of unit pulses having a period of 112*Tc, and each of all the partial correlation functions or each of remaining partial correlation functions, excluding the sixth and seventh partial correlation functions; and
wherein the elimination operation is an operation satisfying algebraic relations in which |A|+|B|\u2212|A\u2212B|=0 in response to real numbers A and B being AB\u22660 and |A|+|B|\u2212|A\u2212B|>0 in response to the real numbers A and B being AB>0.
10. A satellite navigation signal receiver system, comprising:
a front end unit configured to output a received signal obtained by TMBOC(Time-Multiplexed Binary Offset Carrier(6,1,433)-modulating a signal in space (SIS) received from an antenna;
a baseband processing unit configured to acquire and track a code delay value with respect to the output received signal using a DLL (delay locked loop), to compensate for carrier frequency offset using a PLL (phase lock loop), and to extract satellite navigation data from a code delay-compensated local code and a frequency offset-compensated compensated received signal; and
a navigation function processing unit configured to estimate a pseudorange based on the extracted satellite navigation data;
wherein the baseband processing unit operates to:
generate a signal B(t +\u03c4) delayed based on a phase delay \u03c4 with respect to a signal pulse train of a TMBOC(6,1,433)-modulated received signal B(t);
generate partial correlation functions {Pj(\u03c4)}j=011 by performing an autocorrelation operation of the received signal B(t) and the delayed signal B(t+\u03c4) with respect to a total time T(0\u2266t\u2266T);
generate a sub-correlation function R0(\u03c4) by performing an elimination operation of sixth and seventh partial correlation functions P5 (\u03c4) and P6 (\u03c4) and
generate a main correlation function Rproposed(\u03c4) by summing results obtained by performing the elimination operation between each of remaining 10 partial correlation functions {Pj(\u03c4}j=0,j\u22605,611, excluding the sixth and seventh early partial correlation functions P5(\u03c4) and P6(\u03c4) from the 12 partial correlation functions {Pj(\u03c4}j=011, and the sub-correlation function R0(\u03c4);
wherein the elimination operation is an operation satisfying algebraic relations in which |A|+|B|\u2212|A\u2212B|=0 in response to real numbers A and B being AB\u22660and |A|+|B|\u2212|A\u2212B|>0 in response to the real numbers A and B being AB>0.
11. The system of claim 10, wherein
the baseband processing unit is configured to generate the main correlation function according to the equation
R
proposed
\u2061
(
\u03c4
)
=
\u2211
j
=
0
,
j
\u2260
5
,
6
j
=
11
\u2062
\uf603
P
j
\u2061
(
\u03c4
)
\uf604
+
\uf603
R
0
\u2061
(
\u03c4
)
\uf604
–
\uf603
P
j
\u2061
(
\u03c4
)
–
R
0
\u2061
(
\u03c4
)
\uf604
.
12. The system of claim 10, wherein the elimination operation between the sub-correlation function R0(\u03c4) and any one partial correlation function value Pj(\u03c4) comprises a value in an interval of \u2212Tc24 <\u03c4<Tc24.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A headrest adapted to be mounted on a vehicle seat, comprising:
a generally inverted-U-shaped frame provided in said headrest, said generally inverted U-shaped frame having, defined therein, a horizontal frame portion disposed at an upper side of said headrest, and a pair of spaced-apart vertical frame portions extending vertically and continuous from said horizontal frame portion in a direction downwardly of the headrest;
a pair of spaced-apart headrest stays defined integrally in two lower portions respectively of said pair of spaced-apart vertical frame portions, said pair of spaced-apart headrest stays being adapted to be mounted in said vehicle seat;
a single impact absorption bar element having two endpoints that are fixedly connected to said pair of spaced-apart vertical frame portions in such a manner as to extend transversely of said pair of spaced-apart vertical frame portions, while being disposed under, spaced apart from, and substantially parallel to said horizontal frame portion, said impact absorption bar element being of a property prone to deformation only by an excessive great load applied thereto from said head of the seat occupant in case of a rear-end collision or a factor for causing said excessive great load;
a headrest body including a foam padding filled therein;
wherein a substantially midway point of said impact absorption bar element thereof is a recessed or cut-away region, thereby defining a readily deformable region in said substantially midway point,
wherein said horizontal frame portion, said pair of spaced-apart vertical frame portions, and said single impact absorption bar element are embedded integrally in said foam padding of said headrest body, while said pair of spaced-apart headrest stays extend outwardly from said headrest body.