US 5,493,588 A · Multipath compensation for code phase signals

A method of synchronizing to a reference signal the timing of a received composite, code phase SATPS signal, the composite signal consisting of a preferred, interference-free signal distorted by at least one interfering signal, to determine an undistorted timing point of the preferred signal, the method comprising the steps of:

(1) generating a first correlation function A.sub.I (t) representing a timing relationship between a selected reference signal and the reference signal, where the reference signal is a digital signal with a timing cycle of selected length, and where A.sub.I (t) has a peak amplitude at an unknown code phase shift value t=p.sub.I ;
(2) receiving a distorted composite code phase SATPS signal consisting of a preferred, interference-free signal distorted by at least one interfering signal;
(3) generating a second correlation function A.sub.M (t) representing a timing relationship between the composite signal and the reference signal;
(4) determining a nominal peak amplitude A.sub.M (p.sub.M) and the corresponding code phase shift value t=p.sub.M of the second correlation function;
(5) determining a sequence of U early code phase shift values e.sub.I,i <p.sub.I (i=1, . . . , U;
U.gtoreq.2) for the first correlation function A.sub.I (t) for which the code phase shift differences p.sub.I -e.sub.I,i =.DELTA..sub.I,e,i have selected values;
(6) determining a sequence of U early code phase shift values e.sub.M,i <p.sub.M (i=1, . . . , U) for the second correlation function A.sub.M (t) for which the code phase shift differences p.sub.M -e.sub.M,i =.DELTA..sub.M,e,i have selected values;
(7) forming a sequence of U correlation amplitude ratios defined by the relations x.sub.e,i =(A.sub.M (e.sub.M,i)/A.sub.M (p.sub.M))-(A.sub.I (e.sub.I,i)/A.sub.I (p.sub.I)) for i=1, . . . , U;
(8) determining the difference in punctual code phase shift between the first and second correlation functions by the relation
p.sub.M -p.sub.I =F.sub.e (x.sub.e,1, x.sub.e,2, . . . , x.sub.e,U),
where F.sub.e is a selected function of U variables;
and
(9) subtracting the difference p.sub.M -p.sub.I from an apparent time of arrival of the composite code phase SATPS signal to redetermine the time of arrival of this signal.

10 more elements

A method of synchronizing to a reference signal the timing of a received composite, code phase SATPS signal, the composite signal consisting of a preferred, interference-free signal distorted by at least one interfering signal, to determine an undistorted timing point of the preferred signal, the method comprising the steps of:

(1) generating a first correlation function A.sub.I (t) representing a timing relationship between a selected reference signal and the reference signal, where the reference signal is a digital signal with a timing cycle of selected length, and where A.sub.I (t) has a peak amplitude at an unknown code phase shift value t=p.sub.I ;
(2) receiving a distorted composite signal consisting of a preferred, interference-free signal distorted by at least one interfering signal;
(3) generating a second correlation function A.sub.M (t) representing a timing relationship between the composite signal and the reference signal;
(4) determining a nominal peak amplitude A.sub.M (p.sub.M) and the corresponding code phase shift value t=p.sub.M of the second correlation function;
(5) determining a sequence of V late code phase shift values l.sub.I,j >p.sub.I (j =1, . . . , V;
V.gtoreq.2) for the first correlation function A.sub.I (t) for which the code phase shift differences p.sub.I -l.sub.I,j =.DELTA..sub.I,l,j have selected values;
(6) determining a sequence of V late code phase shift values l.sub.M,j >p.sub.M (j=1, . . . , V) for the second correlation function A.sub.M (t) for which the code phase shift differences p.sub.M -l.sub.M,j =.DELTA..sub.M,l,j have selected values;
(7) forming a sequence of V correlation amplitude ratios defined by the relations x.sub.l,i =(A.sub.M (l.sub.M,j)/A.sub.M (p.sub.M))-(A.sub.I (l.sub.I,j)/A.sub.I (p.sub.I)) for j=1, . . . , V;
(8) determining the difference in punctual code phase shift between the first and second correlation functions by the relation
p.sub.M -p.sub.I =F.sub.l (x.sub.l,1,x.sub.l,2, . . . , x.sub.l,V),
where F.sub.l is a selected function of V variables;
and
(9) subtracting the difference p.sub.M -p.sub.I from an apparent time of arrival of the composite code phase SATPS signal to redetermine the time of arrival of this signal.

10 more elements

A method of synchronizing to a reference signal the timing of a received composite, code phase SATPS signal, the composite signal consisting of a preferred, interference-free signal distorted by at least one interfering signal, to determine an undistorted timing point of the preferred signal, the method comprising the steps of:

(1) generating a first correlation function A.sub.I (t) representing a timing relationship between a selected reference signal and the reference signal, where the reference signal is a digital signal with a timing cycle of selected length, and where A.sub.I (t) has a peak amplitude at an unknown code phase shift value t=p.sub.I ;
(2) receiving a distorted composite signal consisting of a preferred, interference-free signal distorted by at least one interfering signal;
(3) generating a second correlation function A.sub.M (t) representing a timing relationship between the composite signal and the reference signal;
(4) determining a nominal peak amplitude A.sub.M (p.sub.M) and the corresponding code phase shift value t=p.sub.M of the second correlation function;
(5) determining a sequence of U early code phase shift values e.sub.I,i <p.sub.I (i=1, . . . , U;
U.gtoreq.1) for the first correlation function A.sub.I (t) for which the code phase shift differences p.sub.I -e.sub.I,i =.DELTA..sub.I,e,i have selected values;
(6) determining a sequence of U early code phase shift values e.sub.M,i <p.sub.M (i=1, . . . , U) for the second correlation function A.sub.M (t) for which the code phase shift differences p.sub.M -e.sub.M,i =.DELTA..sub.M,e,i have selected values;
(7) determining a sequence of V late code phase shift values l.sub.I,j >p.sub.I (j =1, . . . , V;
U+V.gtoreq.2) for the first correlation function A.sub.I (t) for which the code phase shift differences p.sub.I -l.sub.I,j =.DELTA..sub.I,l,j have selected values;
(8) determining a sequence of V late code phase shift values l.sub.M,j >p.sub.M (j=1, . . . , V) for the second correlation function A.sub.M (t) for which the code phase shift differences p.sub.M -l.sub.M,j =.DELTA..sub.M,l,j have selected values;
(9) forming a sequence of L correlation amplitude ratios defined by the relations x.sub.e,i =(A.sub.M (e.sub.M,i)/A.sub.M (p.sub.M)) -(A.sub.I (e.sub.I,i)/A.sub.I (p.sub.I)) for i=1, . . . , U;
(10) forming a sequence Of V correlation amplitude ratios defined by the relations x.sub.l,j =(A.sub.M (l.sub.M,j)/A.sub.M (p.sub.M)) -(A.sub.I (l.sub.I,j)/A.sub.I (p.sub.I)) for j=1, . . . , V;
(11 ) determining the difference in punctual code phase shift between the first and second correlation functions by the relation
p.sub.M -p.sub.I =F(x.sub.e,1, . . . , x.sub.e,U, x.sub.l,1, . . . , x.sub.l,V),
where F is a selected function of U+V variables;
and
(12) subtracting the difference p.sub.M -p.sub.I from an apparent time of arrival of the composite code phase SATPS signal to redetermine the time of arrival of this signal.

14 more elements

A method of synchronizing to a reference signal the timing of a received composite, code phase SATPS signal, the composite signal consisting of a preferred, interference-free signal distorted by at least one interfering signal, to determine an undistorted timing point of the preferred signal, the method comprising the steps of:

(1) generating a first correlation function A.sub.I (t) representing a timing relationship between a selected reference signal and the reference signal, where the reference signal is a digital signal with a timing cycle of selected length, and where A.sub.I (t) has a peak amplitude at an unknown code phase shift value t=p.sub.I ;
(2) receiving a distorted composite signal consisting of a preferred, interference-free signal distorted by at least one interfering signal;
(3) generating a second correlation function A.sub.M (t) representing a timing relationship between the composite signal and the reference signal;
(4) determining a nominal peak amplitude A.sub.M (p.sub.M) and the corresponding code phase shift value t=p.sub.M of the second correlation function;
(5) determining a sequence of U early code phase shift values e.sub.I,i <p.sub.I (i=1, . . . , U;
U.gtoreq.2) for the first correlation function A.sub.I (t) for which the code phase shift amplitude ratios A.sub.I (e.sub.I,i)/A.sub.I (p.sub.I)=r.sub.I,e,i have selected values;
(6) determining a sequence of U early code phase shift values e.sub.M,i <p.sub.M (i=1, . . . , U) for the second correlation function A.sub.M (t) for which the code phase shift amplitude ratios A.sub.M (e.sub.M,i)/A.sub.M (p.sub.M)=r.sub.M,e,i have selected values;
(7) forming a sequence of U code phase shift differences defined by the relations Y.sub.e,i =(p.sub.M -e.sub.M,i)-(p.sub.I -e.sub.I,i) for i=1, . . . , U;
(8) determining the difference in punctual code phase shift between the first and second correlation functions by the relation
p.sub.M -p.sub.I =G.sub.e (y.sub.e,1, y.sub.e,2, . . . , y.sub.e,U),
where G.sub.e is a selected function of U variables;
and
(9) subtracting the difference p.sub.M -p.sub.I from an apparent time of arrival of the composite code phase SATPS signal to redetermine the time of arrival of this signal.

10 more elements

A method of synchronizing to a reference signal the timing of a received composite, code phase SATPS signal, the composite signal consisting of a preferred, interference-free signal distorted by at least one interfering signal, to determine an undistorted timing point of the preferred signal, the method comprising the steps of:

(1) generating a first correlation function A.sub.I (t) representing a timing relationship between a selected reference signal and the reference signal, where the reference signal is a digital signal with a timing cycle of selected length, and where A.sub.I (t) has a peak amplitude at an unknown code phase shift value t=p.sub.I ;
(2) receiving a distorted composite signal consisting of a preferred, interference-free signal distorted by at least one interfering signal;
(3) generating a second correlation function A.sub.M (t) representing a timing relationship between the composite signal and the reference signal;
(4) determining a nominal peak amplitude A.sub.M (p.sub.M) and the corresponding code phase shift value t=p.sub.M of the second correlation function;
(5) determining a sequence of V late code phase shift values l.sub.I,j >p.sub.I (j =1, . . . , V;
V.gtoreq.2) for the first correlation function A.sub.I (t) for which the code phase shift amplitude ratios A.sub.I (l.sub.I,j)/A.sub.I (p.sub.I)=r.sub.I,e,j have selected values;
(6) determining a sequence of V late code phase shift values l.sub.M,j >p.sub.M (j=1, . . . , V) for the second correlation function A.sub.M (t) for which the code phase shift amplitude ratios A.sub.M (l.sub.M,j)/A.sub.M (p.sub.M)=r.sub.M,l,j have selected values;
(7) forming a sequence of V code phase shift differences defined by the relations y.sub.l,j =(p.sub.M -l.sub.M,j)-(p.sub.I -l.sub.I,j) for j=1, . . . , V;
(8) determining the difference in punctual code phase shift between the first and second correlation functions by the relation
p.sub.M -p.sub.I =G.sub.l (y.sub.l,1, y.sub.l,2, . . . , y.sub.l,V),
where G.sub.l is a selected function of V variables;
and
(9) subtracting the difference p.sub.M -p.sub.I from an apparent time of arrival of the composite code phase SATPS signal to redetermine the time of arrival of this signal.

10 more elements

A method of synchronizing to a reference signal the timing of a received composite, code phase SATPS signal, the composite signal consisting of a preferred, interference-free signal distorted by at least one interfering signal, to determine an undistorted timing point of the preferred signal, the method comprising the steps of:

(1) generating a first correlation function A.sub.I (t) representing a timing relationship between a selected reference signal and the reference signal, where the reference signal is a digital signal with a timing cycle of selected length, and where A.sub.I (t) has a peak amplitude at an unknown code phase shift value t=p.sub.I ;
(2) receiving a distorted composite signal consisting of a preferred, interference-free signal distorted by at least one interfering signal;
(3) generating a second correlation function A.sub.M (t) representing a timing relationship between the composite signal and the reference signal;
(4) determining a nominal peak amplitude A.sub.M (p.sub.M) and the corresponding code phase shift value t=p.sub.M of the second correlation function;
(5) determining a sequence of U early code phase shift values e.sub.I,i <p.sub.I (i=1, . . . , U;
U.gtoreq.1) for the first correlation function A.sub.I (t) for which the code phase shift amplitude ratios A.sub.I (e.sub.I,i)/A.sub.I (p.sub.I)=r.sub.I,e,i have selected values;
(6) determining a sequence of U early code phase shift values e.sub.M,i <p.sub.M (i=1, . . . , U) for the second correlation function A.sub.M (t) for which the code phase shift amplitude ratios A.sub.M (e.sub.M,i)/A.sub.M (p.sub.M)=r.sub.M,e,i have selected values;
(7) determining a sequence of V late code phase shift values l.sub.I,j >p.sub.I (j =1, . . . , V;
U+V.gtoreq.2) for the first correlation function A.sub.I (t) for which the code phase shift amplitude ratios A.sub.I (l.sub.I,j)/A.sub.I (p.sub.I)=r.sub.I,e,j have selected values;
(8) determining a sequence of V late code phase shift values l.sub.M,j >p.sub.M (j=1, . . . , V) for the second correlation function A.sub.M (t) for which the code phase shift amplitude ratios A.sub.M (l.sub.M,j)/A.sub.M (p.sub.M)=r.sub.M,l,j have selected values;
(9) forming a sequence of U code phase shift differences defined by the relations y.sub.e,i =(p.sub.M -e.sub.M,i)-(p.sub.I -e.sub.I,i) for i=1, . . . , U;
(10) forming a sequence Of V code phase shift differences defined by the relations y.sub.l,j =(p.sub.M -l.sub.M,j)-(p.sub.I -l.sub.I,j) for j=1, . . . , V;
(11) determining the difference in punctual code phase shift between the first and second correlation functions by the relation
p.sub.M -p.sub.I =G(y.sub.e,1, . . . , y.sub.e,U, y.sub.l,1, . . . , y.sub.l,V),
where G is a selected function of U+V variables;
and
(12) subtracting the difference p.sub.M -p.sub.I from an apparent time of arrival of the composite code phase SATPS signal to redetermine the time of arrival of this signal.

14 more elements

A method of synchronizing to a reference signal the timing of a received composite, code phase SATPS signal, the composite signal consisting of a preferred, interference-free signal distorted by at least one interfering signal, to determine an undistorted timing point of the preferred signal, the method comprising the steps of:

(1) generating a first correlation function A.sub.I (t) representing a timing relationship between a selected reference signal and the reference signal, where the reference signal is a digital signal with a timing cycle of selected length, and where A.sub.I (t) has a peak amplitude at an unknown code phase shift value t=p.sub.I ;
(2) receiving a distorted composite signal consisting of a preferred, interference-free signal distorted by at least one interfering signal;
(3) generating a second correlation function A.sub.M (t) representing a timing relationship between the composite signal and the reference signal;
(4) determining a nominal peak amplitude A.sub.M (p.sub.M) and the corresponding code phase shift value t=p.sub.M of the second correlation function;
(5) determining a sequence of U early code phase shift values e.sub.I,j <p.sub.I (i=1, . . . , U;
U.gtoreq.1) for the first correlation function A.sub.I (t) for which the code phase shift differences p.sub.I -e.sub.I,i =.DELTA..sub.I,e,i have selected values, and forming a first sequence of gradient values B.sub.I,e,i =(A.sub.I (p.sub.I)-A.sub.I (e.sub.I,i))/(p.sub.I -e.sub.I,i);
(6) determining a sequence of U early code phase shift values e.sub.M,i <p.sub.M (i=1, . . . , U) for the second correlation function A.sub.M (t), for which the code phase shift differences p.sub.M -e.sub.M,i =.DELTA..sub.M,e,i have selected values, and forming a second sequence of gradient values B.sub.M,e,i =(A.sub.M (p.sub.M)-A.sub.M (e.sub.M,i))/(p.sub.M -e.sub.M,i);
(7) forming a sequence of U gradient differences z.sub.e,i =B.sub.M,e,i -B.sub.I,e,i for i=1, . . . , U;
(8) determining the difference in punctual code phase shift between the first and second correlation functions by the relation
p.sub.M -p.sub.I =H.sub.e (z.sub.e,1, . . . , z.sub.e,U),
where H.sub.e is a selected function of U variables;
and
(9) subtracting the difference p.sub.M -p.sub.I from an apparent time of arrival of the composite code phase SATPS signal to redetermine the time of arrival of this signal.

10 more elements

A method of synchronizing to a reference signal the timing of a received composite, code phase SATPS signal, the composite signal consisting of a preferred, interference-free signal distorted by at least one interfering signal, to determine an undistorted timing point of the preferred signal, the method comprising the steps of:

(1) generating a first correlation function A.sub.I (t) representing a timing relationship between a selected reference signal and the reference signal, where the reference signal is a digital signal with a timing cycle of selected length, and where A.sub.I (t) has a peak amplitude at an unknown code phase shift value t=p.sub.I ;
(2) receiving a distorted composite signal consisting of a preferred, interference-free signal distorted by at least one interfering signal;
(3) generating a second correlation function A.sub.M (t) representing a timing relationship between the composite signal and the reference signal;
(4) determining a nominal peak amplitude A.sub.M (p.sub.M) and the corresponding code phase shift value t=p.sub.M of the second correlation function;
(5) determining a sequence of V late code phase shift values l.sub.I,j >p.sub.I (j =1, . . . , V;
V.gtoreq.1) for the first correlation function A.sub.I (t) for which the code phase shift differences p.sub.I -l.sub.I,j =.DELTA..sub.I,l,j have selected values, and forming a first sequence of gradient values B.sub.I,l,j =(A.sub.I (p.sub.I)-A.sub.I (l.sub.I,j))/(p.sub.I -l.sub.I,j);
(6) determining a sequence of V late code phase shift values l.sub.M,j >p.sub.M (j=1, . . . , V) for the second correlation function A.sub.M (t), for which the code phase shift differences p.sub.M -l.sub.M,j =.DELTA..sub.M,l,j have selected values, and forming a second sequence of gradient values B.sub.M,l,j =(A.sub.M (p.sub.M)-A.sub.M (l.sub.M,j))/(p.sub.M -l.sub.M,j);
(7) forming a sequence of V gradient differences z.sub.l,j =B.sub.M,l,j -B.sub.I,l,j for j=1, . . . , V;
(8) determining the difference in punctual code phase shift between the first and second correlation functions by the relation
p.sub.M -p.sub.I =H.sub.l (z.sub.l,1, . . . , z.sub.l,V),
where H.sub.l is a selected function of V variables;
and
(9) subtracting the difference p.sub.M -p.sub.I from an apparent time of arrival of the composite code phase SATPS signal to redetermine the time of arrival of this signal.

10 more elements

A method of synchronizing to a reference signal the timing of a received composite, code phase SATPS signal, the composite signal consisting of a preferred, interference-free signal distorted by at least one interfering signal, to determine an undistorted timing point of the preferred signal, the method comprising the steps of:

(1) generating a first correlation function A.sub.I (t) representing a timing relationship between a selected reference signal and the reference signal, where the reference signal is a digital signal with a timing cycle of selected length, and where A.sub.I (t) has a peak amplitude at an unknown code phase shift value t=p.sub.I ;
(2) receiving a distorted composite signal consisting of a preferred, interference-free signal distorted by at least one interfering signal;
(3) generating a second correlation function A.sub.M (t) representing a timing relationship between the composite signal and the reference signal;
(4) determining a nominal peak amplitude A.sub.M (p.sub.M) and the corresponding code phase shift value t=p.sub.M of the second correlation function;
(5) determining a sequence of U early code phase shift values e.sub.I,i <p.sub.I (i=1, . . . , U;
U.gtoreq.1) for the first correlation function A.sub.I (t) for which the code phase shift differences p.sub.I -e.sub.I,i =.DELTA..sub.I,e,i have selected values, and forming a first sequence of gradient values B.sub.I,e,i =(A.sub.I (p.sub.I)-A.sub.I (e.sub.I,i))/(p.sub.I -e.sub.I,i);
(6) determining a sequence of U early code phase shift values e.sub.M,i <p.sub.M (i=1, . . . , U) for the second correlation function A.sub.M (t) for which the code phase shift differences p.sub.M -e.sub.M,i =.DELTA..sub.M,e,i have selected values, and forming a second sequence of gradient values B.sub.M,e,i =(A.sub.M (p.sub.M)-A.sub.M (e.sub.M,i))/(p.sub.M -e.sub.M,i);
(7) determining a sequence of V late code phase shift values l.sub.I,j >p.sub.I (j =1, . . . , V;
U+V.gtoreq.2) for the first correlation function A.sub.I (t) for which the code phase shift p.sub.I -e.sub.I,j =.DELTA..sub.I,e,j have selected values and forming a first sequence of gradient values B.sub.I,l,j =(A.sub.I (p.sub.I)-A.sub.I (l.sub.I,j))/(p.sub.I -l.sub.I,j);
(8) determining a sequence of V late code phase shift values l.sub.M,j >p.sub.M (j=1, . . . , V) for the second correlation function A.sub.M (t) for which the code phase shift differences p.sub.M -l.sub.M,j =.DELTA..sub.M,l,j have selected values, and forming a second sequence of gradient values B.sub.M,l,j =(A.sub.M (p.sub.M)-A.sub.M (l.sub.M,j))/(p.sub.M -l.sub.M,j);
(9) forming a sequence of U gradient differences z.sub.e,i =B.sub.M,e,i -B.sub.I,e,i for i=1, . . . , U;
(10) forming a sequence of V gradient differences z.sub.e,j =B.sub.M,e,j -B.sub.I,e,j for j=1, . . . , V;
(11) determining the difference in punctual code phase shift between the first and second correlation functions by the relation
p.sub.M -p.sub.I =H(z.sub.e,1, . . . , z.sub.e,U, z.sub.l,1, . . . , z.sub.l,V),
where H is a selected function of U+V variables;
and
(12) subtracting the difference p.sub.M -p.sub.I from an apparent time of arrival of the composite code phase SATPS signal to redetermine the time of arrival of this signal.

14 more elements

A method of synchronizing to a reference signal the timing of a received composite, code phase SATPS signal, the composite signal consisting of a preferred, interference-free signal distorted by at least one interfering signal, to determine an undistorted timing point of the preferred signal, the method comprising the steps of:

(1) generating a first correlation function A.sub.I (t) representing a timing relationship between a selected reference signal and the reference signal, where the reference signal is a digital signal with a timing cycle of selected length, and where A.sub.I (t) has a peak amplitude at an unknown code phase shift value t=p.sub.I ;
(2) receiving a distorted composite signal consisting of a preferred, interference-free signal distorted by at least one interfering signal;
(3) generating a second correlation function A.sub.M (t) representing a timing relationship between the composite signal and the reference signal;
(4) determining a nominal peak amplitude A.sub.M (p.sub.M) and the corresponding code phase shift value t=p.sub.M of the second correlation function;
(5) determining a sequence of U early code phase shift values e.sub.I,i <p.sub.I (i=1, . . . , U;
U.gtoreq.1) for the first correlation function A.sub.I (t) for which the correlation amplitude ratios r.sub.I,e,i =A.sub.I (e.sub.I,i)/A.sub.I (p.sub.I) have selected values, and forming a first sequence of gradient values B.sub.I,e,i =(A.sub.I (p.sub.I)-A.sub.I (e.sub.I,i))/(p.sub.I -e.sub.I,i);
(6) determining a sequence of U early code phase shift values e.sub.M,i <p.sub.M (i=1, . . . , U) for the second correlation function A.sub.M (t), for which the correlation amplitude ratios r.sub.M,e,i =A.sub.M (e.sub.M,i)/A.sub.M (p.sub.M) have selected values, and forming a second sequence of gradient values B.sub.M,e,i =(A.sub.M (p.sub.M) -A.sub.M (e.sub.M,i))/(p.sub.M -e.sub.M,i);
(7) forming a sequence of U gradient differences z.sub.e,i =B.sub.M,e,i -B.sub.I,e,i for i=1, . . . , U;
(8) determining the difference in punctual code phase shift between the first and second correlation functions by the relation
p.sub.M -p.sub.I =K.sub.e (z.sub.e,1, . . . , z.sub.e,U),
where K.sub.e is a selected function of U variables;
and
(9) subtracting the difference p.sub.M -p.sub.I from an apparent time of arrival of the composite code phase SATPS signal to redetermine the time of arrival of this signal.

10 more elements

A method of synchronizing to a reference signal the timing of a received composite, code phase SATPS signal, the composite signal consisting of a preferred, interference-free signal distorted by at least one interfering signal, to determine an undistorted timing point of the preferred signal, the method comprising the steps of:

(1) generating a first correlation function A.sub.I (t) representing a timing relationship between a selected reference signal and the reference signal, where the reference signal is a digital signal with a timing cycle of selected length, and where A.sub.I (t) has a peak amplitude at an unknown code phase shift value t=P.sub.I ;
(2) receiving a distorted composite signal consisting of a preferred, interference-free signal distorted by at least one interfering signal;
(3) generating a second correlation function A.sub.M (t) representing a timing relationship between the composite signal and the reference signal;
(4) determining a nominal peak amplitude A.sub.M (p.sub.M) and the corresponding code phase shift value t=p.sub.M of the second correlation function;
(5) determining a sequence of V late code phase shift values l.sub.i,j >p.sub.I (j =1, . . . , V;
V.gtoreq.1) for the first correlation function A.sub.I (t.sub.), for which the correlation amplitude ratios r.sub.I,l,j =A.sub.I (l.sub.I,j)/A.sub.I (p.sub.I) have selected values, and forming a sequence of gradient values B.sub.I,l,j =(A.sub.I (p.sub.I)-A.sub.I (l.sub.I,j))/(p.sub.I -l.sub.I,j);
(6) determining a sequence of V late code phase shift values l.sub.M,j >p.sub.M (j=1, . . . , V) for the second correlation function A.sub.M (t), for which the correlation amplitude ratios r.sub.M,l,j =A.sub.M (l.sub.M,l)/A.sub.M (p.sub.M) have selected values, and forming a sequence of gradient values B.sub.M,l,j =(A.sub.M (p.sub.M)-A.sub.M (l.sub.M,j))/(p.sub.M -l.sub.M,j);
(7) forming a sequence of V gradient differences z.sub.l,j =B.sub.M,l,j -B.sub.I,l,j for j=1, . . . ,V;
(8) determining the difference in punctual code phase shift between the first and second correlation functions by the relation
p.sub.M -p.sub.I =K.sub.l (z.sub.l,1, . . . , z.sub.l,V),
where K.sub.l is a selected function of V variables;
and
(9) subtracting the difference p.sub.M -p.sub.I from an apparent time of arrival of the composite code phase SATPS signal to redetermine the time of arrival of this signal.

10 more elements

A method of synchronizing to a reference signal the timing of a received composite, code phase SATPS signal, the composite signal consisting of a preferred, interference-free signal distorted by at least one interfering signal, to determine an undistorted timing point of the preferred signal, the method comprising the steps of:

(1) generating a first correlation function A.sub.I (t) representing a timing relationship between a selected reference signal and the reference signal, where the reference signal is a digital signal with a timing cycle of selected length, and where A.sub.I (t) has a peak amplitude at an unknown code phase shift value t=p.sub.I ;
(2) receiving a distorted composite signal consisting of a preferred, interference-free signal distorted by at least one interfering signal;
(3) generating a second correlation function A.sub.M (t) representing a timing relationship between the composite signal and the reference signal;
(4) determining a nominal peak amplitude A.sub.M (p.sub.M) and the corresponding code phase shift value t=p.sub.M of the second correlation function;
(5) determining a sequence of U early code phase shift values e.sub.I,i <p.sub.I (i=1, . . . , U;
U.gtoreq.1) for the first correlation function A.sub.I (t) for which the correlation amplitude ratios r.sub.I,e,i =A.sub.I (e.sub.I,i)/A.sub.I (p.sub.I) have selected values, and forming a first sequence of gradient values B.sub.I,e,i =(A.sub.I (p.sub.I)-A.sub.I (e.sub.I,i))/(p.sub.I -e.sub.I,i);
(6) determining a sequence of U early code phase shift values e.sub.M,i <p.sub.M (i=1, . . . , U) for the second correlation function A.sub.M (t) for which the correlation amplitude ratios r.sub.M,e,i =A.sub.M (e.sub.M,i)/A.sub.M (p.sub.M) have selected values, and forming a second sequence of gradient values B.sub.M,e,i =(A.sub.M (p.sub.M) -A.sub.M (e.sub.M,i))/(p.sub.M -e.sub.M,i);
(7) determining a sequence of V late code phase shift values l.sub.I,j >p.sub.I (j =1, . . . , V;
U+V.gtoreq.1) for the first correlation function A.sub.I (t) for which the correlation amplitude ratios r.sub.I,l,j =A.sub.I (l.sub.I,j)/A.sub.I (p.sub.I) have selected values and forming a sequence of gradient values B.sub.I,l,j =(A.sub.I (p.sub.I)-A.sub.I (l.sub.I,j))/(p.sub.I -l.sub.I,j);
(8) determining a sequence of V late code phase shift values l.sub.M,j >p.sub.M (j=1, . . . , V) for the second correlation function A.sub.M (t) for which the correlation amplitude ratios r.sub.M,l,j =A.sub.M (l.sub.M,l)/A.sub.M (p.sub.M) have selected values, and forming a sequence of gradient values B.sub.M,l,j =(A.sub.M (p.sub.M)-A.sub.M (l.sub.M,j))/(p.sub.M -l.sub.M,j);
(9) forming a sequence of U gradient differences z.sub.e,i =B.sub.M,e,i -B.sub.I,e,i for i=1, . . . , U;
(10) forming a sequence of V gradient differences z.sub.l,j =B.sub.M,l,j -B.sub.I,l,j for j=1, . . . , V;
(11) determining the difference in punctual code phase shift between the first and second correlation functions by the relation
p.sub.M -p.sub.I =K(z.sub.e,1, . . . , z.sub.e,U, z.sub.l,1, . . . , z.sub.l,V),
where K is a selected function of U+V variables;
and
(12) subtracting the difference p.sub.M -p.sub.I from an apparent time of arrival of the composite code phase SATPS signal to redetermine the time of arrival of this signal.

14 more elements

A method of synchronizing to a reference signal the timing of a received composite, code phase SATPS signal, the composite signal consisting of a preferred, interference-free signal distorted by at least one interfering signal, to determine an undistorted timing point of the preferred signal, the method comprising the steps of:

receiving a selected reference signal S.sub.ref (t) and generating an in-phase reference signal component S.sub.ref,in-phase (t) and a quadrature reference signal component S.sub.ref,quad (t) from this reference signal, where the reference signal is a digital signal with a timing cycle of selected length, and where A.sub.I (t) has a peak amplitude at an unknown code phase shift value t=p.sub.I ;
receiving a composite signal S.sub.comp (t), consisting of a preferred, interference-free signal distorted by at least one interfering signal, and generating an in-phase reference signal component S.sub.comp,in-phase (t) and a quadrature reference signal component S.sub.comp,quad (t) from this composite signal;
generating a first correlation function A.sub.I,in-phase (t) representing a timing relationship between the signal S.sub.ref,in-phase (t) and the signal S.sub.comp,in-phase (t);
generating a second correlation function A.sub.M,in-phase (t) representing a timing relationship between the signal S.sub.ref,in-phase (t) and the signal S.sub.comp,in-phase (t);
generating a third correlation function A.sub.I,quad (t) representing a timing relationship between the signal S.sub.ref,quad (t) and the signal S.sub.comp,quad (t);
generating a fourth correlation function A.sub.M,quad (t) representing a timing relationship between the signal S.sub.ref,quad (t) and the signal S.sub.comp,quad (t);
generating a first combined correlation function
A.sub.I (t)=[(A.sub.I,in-phase (t)).sup.2 +(A.sub.I,quad (t)).sup.2 ].sup.1/2 ;
generating a second combined correlation function
A.sub.M (t)=[(A.sub.M,in-phase (t)).sup.2 +(A.sub.M,quad (t)).sup.2 ].sup.1/2 ;
and
determining a nominal peak amplitude A.sub.I (p.sub.I) and the corresponding code phase shift value t=p.sub.I of the first combined correlation function;
determining a nominal peak amplitude A.sub.M (p.sub.M) and the corresponding code phase shift value t=p.sub.M of the first combined correlation function;
determining a sequence of U early code phase shift values e.sub.I,i <p.sub.I (i=1, . . . , U;
U.gtoreq.1) for the first correlation function A.sub.I (t) for which the code phase shift differences p.sub.I -e.sub.I,i =.DELTA..sub.I,e,i have selected values;
determining a sequence of U early code phase shift values e.sub.M,i <p.sub.M (i =1, . . . , U) for the second correlation function A.sub.M (t) for which the code phase shift differences p.sub.M -e.sub.M,i =.DELTA..sub.M,e,i have selected values;
forming a sequence of U correlation amplitude ratios defined by the relations x.sub.e,i =(A.sub.M (e.sub.M,i)/A.sub.M (p.sub.M))-(A.sub.I (e.sub.I,i)/A.sub.I (p.sub.I)) for i=1, . . . , U;
and
determining the difference in punctual code phase shift between the first and second correlation functions by the relation
p.sub.M -p.sub.I =F.sub.e (x.sub.e,1, x.sub.e,2, . . . , x.sub.e,U),
where F.sub.e is a selected function of U variables.

18 more elements

A method of synchronizing to a reference signal the timing of a received composite, code phase SATPS signal, the composite signal consisting of a preferred, interference-free signal distorted by at least one interfering signal, to determine an undistorted timing point of the preferred signal, the method comprising the steps of:

receiving a composite signal S.sub.comp (t), consisting of a preferred, interference-free signal distorted by at least one interfering signal, and generating an in-phase reference signal component S.sub.comp,in-phase (t) and a quadrature reference signal component S.sub.comp,quad (t) from this composite signal;
generating a first correlation function A.sub.I,in-phase (t) representing a timing relationship between the signal S.sub.ref,in-phase (t) and the signal S.sub.comp,in-phase (t);
generating a second correlation function A.sub.M,in-phase (t) representing a timing relationship between the signal S.sub.ref,in-phase (t) and the signal S.sub.comp,in-phase (t);
generating a third correlation function A.sub.I,quad (t) representing a timing relationship between the signal S.sub.ref,quad (t) and the signal S.sub.comp,quad (t);
generating a fourth correlation function A.sub.M,quad (t) representing a timing relationship between the signal S.sub.ref,quad (t) and the signal S.sub.comp,quad (t);
generating a first combined correlation function
A.sub.I (t)=[(A.sub.I,in-phase (t)).sup.2 +(A.sub.I,quad (t)).sup.2 ].sup.1/2 ;
generating a second combined correlation function
A.sub.M (t)=[(A.sub.M,in-phase (t)).sup.2 +(A.sub.M,quad (t)).sup.2 ].sup.1/2 ;
and
determining a nominal peak amplitude A.sub.I (p.sub.I) and the corresponding code phase shift value t=p.sub.I of the first combined correlation function;
determining a nominal peak amplitude A.sub.M (p.sub.M) and the corresponding code phase shift value t=p.sub.M of the first combined correlation function;
determining a sequence of V late code phase shift values l.sub.I,j >p.sub.I (j=1, . . . , V;
V.gtoreq.1) for the first correlation function A.sub.I (t) for which the code phase shift differences p.sub.I -l.sub.I,j =.DELTA..sub.I,l,j have selected values;
determining a sequence of V late code phase shift values l.sub.M,j >p.sub.M (j=1, . . . , V) for the second correlation function A.sub.M (t) for which the code phase shift differences p.sub.M -l.sub.M,i =.DELTA..sub.M,l,j have selected values;
forming a sequence of V correlation amplitude ratios defined by the relations x.sub.l,i =(A.sub.M (l.sub.M,j)/A.sub.M (p.sub.M))-(A.sub.I (l.sub.I,j)/A.sub.I (p.sub.I)) for j=1, . . . , V;
determining the difference in punctual code phase shift between the first and second correlation functions by the relation
p.sub.M -p.sub.I =F.sub.l (x.sub.l,1, x.sub.l,2, . . . , x.sub.l,V),
where F.sub.l is a selected function of V variables;
and
subtracting the difference p.sub.M -p.sub.I from an apparent, time of arrival of the composite code phase SATPS signal to redetermine the time of arrival of this signal.

18 more elements

A method of synchronizing to a reference signal the timing of a received composite, code phase SATPS signal, the composite signal consisting of a preferred, interference-free signal distorted by at least one interfering signal, to determine an undistorted timing point of the preferred signal, the method comprising the steps of:

receiving a selected reference signal S.sub.ref (t) and generating an in-phase reference signal component S.sub.ref,in-phase (t) and a quadrature reference signal component S.sub.ref,quad (t) from this reference signal, where the reference signal is a digital signal with a timing cycle of selected length, and where A.sub.I (t) has a peak amplitude at an unknown code phase shift value t=p.sub.I ;
receiving a composite signal S.sub.comp (t), consisting of a preferred, interference-free signal distorted by at least one interfering signal, and generating an in-phase reference signal component S.sub.comp,in-phase (t) and a quadrature reference signal component S.sub.comp,quad (t) from this composite signal;
generating a first correlation function A.sub.I,in-phase (t) representing a timing relationship between the signal S.sub.ref,in-phase (t) and the signal S.sub.comp,in-phase (t);
generating a second correlation function A.sub.M,in-phase (t) representing a timing relationship between the signal S.sub.ref,in-phase (t) and the signal S.sub.comp,in-phase (t);
generating a third correlation function A.sub.I,quad (t) representing a timing relationship between the signal S.sub.ref,quad (t) and the signal S.sub.comp,quad (t);
generating a fourth correlation function A.sub.M,quad (t) representing a timing relationship between the signal S.sub.ref,quad (t) and the signal S.sub.comp,quad (t);
generating a first combined correlation function
A.sub.I (t)=[(A.sub.I,in-phase (t)).sup.2 +(A.sub.I,quad (t)).sup.2 ].sup.1/2 ;
generating a second combined correlation function
A.sub.M (t)=[(A.sub.M,in-phase (t)).sup.2 +(A.sub.M,quad (t)).sup.2 ].sup.1/2 ;
and
determining a nominal peak amplitude A.sub.I (p.sub.I) and the corresponding code phase shift value t=p.sub.I of the first combined correlation function;
determining a nominal peak amplitude A.sub.M (p.sub.M) and the corresponding code phase shift value t=p.sub.M of the first combined correlation function;
determining a sequence of U early code phase shift values e.sub.I,i <p.sub.I (i=1, . . . , U;
U.gtoreq.1) for the first correlation function A.sub.I (t) for which the code phase shift amplitude ratios A.sub.I (e.sub.I,i)/A.sub.I (p.sub.I)=r.sub.I,e,i have selected values;
determining a sequence of U early code phase shift values e.sub.M,i <p.sub.M (i =1, . . . , U) for the second correlation function A.sub.M (t) for which the code phase shift amplitude ratios A.sub.M (e.sub.M,i)/A.sub.M (p.sub.M)=r.sub.M,e,i have selected values;
forming a sequence of U code phase shift differences defined by the relations y.sub.e,i =(p.sub.M -e.sub.M,i)-(p.sub.I -e.sub.I,i) for i=1, . . . , U;
and
determining the difference in punctual code phase shift between the first and second correlation functions by the relation
p.sub.M -p.sub.I =G.sub.e (y.sub.e,1, y.sub.e,2, . . . , y.sub.e,U),
where G.sub.e is a selected function of U variables.

18 more elements

A method of synchronizing to a reference signal the timing of a received composite, code phase SATPS signal, the composite signal consisting of a preferred, interference-free signal distorted by at least one interfering signal, to determine an undistorted timing point of the preferred signal, the method comprising the steps of:

receiving a selected reference signal S.sub.ref (t) and generating an in-phase reference signal component S.sub.ref,in-phase (t) and a quadrature reference signal component S.sub.ref,quad (t) from this reference signal, where the reference signal is a digital signal with a timing cycle of selected length, and where A.sub.I (t) has a peak amplitude at an unknown code phase shift value t=p.sub.I ;
receiving a composite signal S.sub.comp (t), consisting of a preferred, interference-free signal distorted by at least one interfering signal, and generating an in-phase reference signal component S.sub.comp,in-phase (t) and a quadrature reference signal component S.sub.comp,quad (t) from this composite signal;
generating a first correlation function A.sub.I,in-phase (t) representing a timing relationship between the signal S.sub.ref,in-phase (t) and the signal S.sub.comp,in-phase (t);
generating a second correlation function A.sub.M,in-phase (t) representing a timing relationship between the signal S.sub.ref,in-phase (t) and the signal S.sub.comp,in-phase (t);
generating a third correlation function A.sub.I,quad (t) representing a timing relationship between the signal S.sub.ref,quad (t) and the signal S.sub.comp,quad (t);
generating a fourth correlation function A.sub.M,quad (t) representing a timing relationship between the signal S.sub.ref,quad (t) and the signal S.sub.comp,quad (t);
generating a first combined correlation function
A.sub.I (t)=[(A.sub.I,in-phase (t)).sup.2 +(A.sub.I,quad (t)).sup.2 ].sup.1/2 ;
generating a second combined correlation function
A.sub.M (t)=[(A.sub.M,in-phase (t)).sup.2 +(A.sub.M,quad (t)).sup.2 ].sup.1/2 ;
and
determining a nominal peak amplitude A.sub.I (p.sub.I) and the corresponding code phase shift value t=p.sub.I of the first combined correlation function;
determining a nominal peak amplitude A.sub.M (p.sub.M) and the corresponding code phase shift value t=p.sub.M of the first combined correlation function;
determining a sequence of V late code phase shift values l.sub.I,j >p.sub.I (j=1, . . . , V;
V.gtoreq.1) for the first correlation function A.sub.I (t) for which the code phase shift amplitude ratios A.sub.I (l.sub.I,j)/A.sub.I (p.sub.I)=r.sub.I,e,j have selected values;
determining a sequence of V late code phase shift values l.sub.M,j >p.sub.M (j=1, . . . , V) for the second correlation function A.sub.M (t) for which the code phase shift amplitude ratios A.sub.M (l.sub.M,j)/A.sub.M (p.sub.M)=r.sub.M,l,j have selected values;
forming a sequence of V code phase shift differences defined by the relations y.sub.l,j =(p.sub.M -l.sub.M,j)-(p.sub.I -l.sub.I,j) for j=1, . . . , V;
and
determining the difference in punctual code phase shift between the first and second correlation functions by the relation
p.sub.M -p.sub.I =G.sub.l (y.sub.l,1, y.sub.l,2, . . . , y.sub.l,V),
where G.sub.l is a selected function of V variables.

18 more elements

Multipath compensation for code phase signals

Life of this patent

Multipath compensation for code phase signals

Life of this patent

Abstract

Claims28