Multipath compensation for code phase signals
First Claim
1. 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 AI (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 AI (t) has a peak amplitude at an unknown code phase shift value t=pI ;
(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 AM (t) representing a timing relationship between the composite signal and the reference signal;
(4) determining a nominal peak amplitude AM (pM) and the corresponding code phase shift value t=pM of the second correlation function;
(5) determining a sequence of U early code phase shift values eI,i <
pI (i=1, . . . , U;
U≧
2) for the first correlation function AI (t) for which the code phase shift differences pI -eI,i =Δ
I,e,i have selected values;
(6) determining a sequence of U early code phase shift values eM,i <
pM (i=1, . . . , U) for the second correlation function AM (t) for which the code phase shift differences pM -eM,i =Δ
M,e,i have selected values;
(7) forming a sequence of U correlation amplitude ratios defined by the relations xe,i =(AM (eM,i)/AM (pM))-(AI (eI,i)/AI (pI)) for i=1, . . . , U;
(8) determining the difference in punctual code phase shift between the first and second correlation functions by the relation
space="preserve" listing-type="equation">p.sub.M -p.sub.I =F.sub.e (x.sub.e,1, x.sub.e,2, . . . , x.sub.e,U),where Fe is a selected function of U variables; and
(9) subtracting the difference pM -pI from an apparent time of arrival of the composite code phase SATPS signal to redetermine the time of arrival of this signal.
3 Assignments
0 Petitions
Accused Products
Abstract
Methods for synchronizing to a reference signal the timing of a received composite, code phase SATPS signal, which consists of a preferred, interference-free signal distorted by at least one interfering signal, to determine an undistorted timing point of the preferred signal. An idealized correlation function AI (t), formed from the product of a digital reference signal with a time-shifted reference signal, and a measured correlation signal AM (t), formed from the product of a received signal and a time-shifted reference signal, are computed. Peak amplitudes AM (pM) and AI (pI) are found for the respective measurable and idealized punctual code phase shifts pM and pI. In a first embodiment of the invention, the correlation measurements formed on the early side (or on the late side) of the peak for the correlation function A(t) are combined to form an estimate of the time delay associated with a multipath signal. In a second embodiment, correlation measurements formed on both the early and late sides of the peak are combined to form an estimate of the multipath time delay. In a third embodiment, a gradient difference is formed from two sets of correlation measurements to estimate the multipath time delay. In a fourth embodiment, correlation functions formed from in-phase and quadrature signals are used to estimate the multipath time delay. This fourth embodiment allows code phase multipath time delay to be measured in the absence of receiver carrier phase lock. All four embodiments may be used in a fixed amplitude variable time (FAVT) mode and in a fixed time variable amplitude (FTVA) mode.
62 Citations
28 Claims
-
1. 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 AI (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 AI (t) has a peak amplitude at an unknown code phase shift value t=pI ; (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 AM (t) representing a timing relationship between the composite signal and the reference signal; (4) determining a nominal peak amplitude AM (pM) and the corresponding code phase shift value t=pM of the second correlation function; (5) determining a sequence of U early code phase shift values eI,i <
pI (i=1, . . . , U;
U≧
2) for the first correlation function AI (t) for which the code phase shift differences pI -eI,i =Δ
I,e,i have selected values;(6) determining a sequence of U early code phase shift values eM,i <
pM (i=1, . . . , U) for the second correlation function AM (t) for which the code phase shift differences pM -eM,i =Δ
M,e,i have selected values;(7) forming a sequence of U correlation amplitude ratios defined by the relations xe,i =(AM (eM,i)/AM (pM))-(AI (eI,i)/AI (pI)) for i=1, . . . , U; (8) determining the difference in punctual code phase shift between the first and second correlation functions by the relation
space="preserve" listing-type="equation">p.sub.M -p.sub.I =F.sub.e (x.sub.e,1, x.sub.e,2, . . . , x.sub.e,U),where Fe is a selected function of U variables; and (9) subtracting the difference pM -pI from an apparent time of arrival of the composite code phase SATPS signal to redetermine the time of arrival of this signal. - View Dependent Claims (2)
-
-
3. 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 AI (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 AI (t) has a peak amplitude at an unknown code phase shift value t=pI ; (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 AM (t) representing a timing relationship between the composite signal and the reference signal; (4) determining a nominal peak amplitude AM (pM) and the corresponding code phase shift value t=pM of the second correlation function; (5) determining a sequence of V late code phase shift values lI,j >
pI (j =1, . . . , V;
V≧
2) for the first correlation function AI (t) for which the code phase shift differences pI -lI,j =Δ
I,l,j have selected values;(6) determining a sequence of V late code phase shift values lM,j >
pM (j=1, . . . , V) for the second correlation function AM (t) for which the code phase shift differences pM -lM,j =Δ
M,l,j have selected values;(7) forming a sequence of V correlation amplitude ratios defined by the relations xl,i =(AM (lM,j)/AM (pM))-(AI (lI,j)/AI (pI)) for j=1, . . . , V; (8) determining the difference in punctual code phase shift between the first and second correlation functions by the relation
space="preserve" listing-type="equation">p.sub.M -p.sub.I =F.sub.l (x.sub.l,1,x.sub.l,2, . . . , x.sub.l,V),where Fl is a selected function of V variables; and (9) subtracting the difference pM -pI from an apparent time of arrival of the composite code phase SATPS signal to redetermine the time of arrival of this signal. - View Dependent Claims (4)
-
-
5. 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 AI (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 AI (t) has a peak amplitude at an unknown code phase shift value t=pI ; (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 AM (t) representing a timing relationship between the composite signal and the reference signal; (4) determining a nominal peak amplitude AM (pM) and the corresponding code phase shift value t=pM of the second correlation function; (5) determining a sequence of U early code phase shift values eI,i <
pI (i=1, . . . , U;
U≧
1) for the first correlation function AI (t) for which the code phase shift differences pI -eI,i =Δ
I,e,i have selected values;(6) determining a sequence of U early code phase shift values eM,i <
pM (i=1, . . . , U) for the second correlation function AM (t) for which the code phase shift differences pM -eM,i =Δ
M,e,i have selected values;(7) determining a sequence of V late code phase shift values lI,j >
pI (j =1, . . . , V;
U+V≧
2) for the first correlation function AI (t) for which the code phase shift differences pI -lI,j =Δ
I,l,j have selected values;(8) determining a sequence of V late code phase shift values lM,j >
pM (j=1, . . . , V) for the second correlation function AM (t) for which the code phase shift differences pM -lM,j =Δ
M,l,j have selected values;(9) forming a sequence of L correlation amplitude ratios defined by the relations xe,i =(AM (eM,i)/AM (pM)) -(AI (eI,i)/AI (pI)) for i=1, . . . , U; (10) forming a sequence Of V correlation amplitude ratios defined by the relations xl,j =(AM (lM,j)/AM (pM)) -(AI (lI,j)/AI (pI)) for j=1, . . . , V; (11 ) determining the difference in punctual code phase shift between the first and second correlation functions by the relation
space="preserve" listing-type="equation">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 pM -pI from an apparent time of arrival of the composite code phase SATPS signal to redetermine the time of arrival of this signal. - View Dependent Claims (6)
-
-
7. 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 AI (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 AI (t) has a peak amplitude at an unknown code phase shift value t=pI ; (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 AM (t) representing a timing relationship between the composite signal and the reference signal; (4) determining a nominal peak amplitude AM (pM) and the corresponding code phase shift value t=pM of the second correlation function; (5) determining a sequence of U early code phase shift values eI,i <
pI (i=1, . . . , U;
U≧
2) for the first correlation function AI (t) for which the code phase shift amplitude ratios AI (eI,i)/AI (pI)=rI,e,i have selected values;(6) determining a sequence of U early code phase shift values eM,i <
pM (i=1, . . . , U) for the second correlation function AM (t) for which the code phase shift amplitude ratios AM (eM,i)/AM (pM)=rM,e,i have selected values;(7) forming a sequence of U code phase shift differences defined by the relations Ye,i =(pM -eM,i)-(pI -eI,i) for i=1, . . . , U; (8) determining the difference in punctual code phase shift between the first and second correlation functions by the relation
space="preserve" listing-type="equation">p.sub.M -p.sub.I =G.sub.e (y.sub.e,1, y.sub.e,2, . . . , y.sub.e,U),where Ge is a selected function of U variables; and (9) subtracting the difference pM -pI from an apparent time of arrival of the composite code phase SATPS signal to redetermine the time of arrival of this signal. - View Dependent Claims (8)
-
-
9. 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 AI (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 AI (t) has a peak amplitude at an unknown code phase shift value t=pI ; (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 AM (t) representing a timing relationship between the composite signal and the reference signal; (4) determining a nominal peak amplitude AM (pM) and the corresponding code phase shift value t=pM of the second correlation function; (5) determining a sequence of V late code phase shift values lI,j >
pI (j =1, . . . , V;
V≧
2) for the first correlation function AI (t) for which the code phase shift amplitude ratios AI (lI,j)/AI (pI)=rI,e,j have selected values;(6) determining a sequence of V late code phase shift values lM,j >
pM (j=1, . . . , V) for the second correlation function AM (t) for which the code phase shift amplitude ratios AM (lM,j)/AM (pM)=rM,l,j have selected values;(7) forming a sequence of V code phase shift differences defined by the relations yl,j =(pM -lM,j)-(pI -lI,j) for j=1, . . . , V; (8) determining the difference in punctual code phase shift between the first and second correlation functions by the relation
space="preserve" listing-type="equation">p.sub.M -p.sub.I =G.sub.l (y.sub.l,1, y.sub.l,2, . . . , y.sub.l,V),where Gl is a selected function of V variables; and (9) subtracting the difference pM -pI from an apparent time of arrival of the composite code phase SATPS signal to redetermine the time of arrival of this signal. - View Dependent Claims (10)
-
-
11. 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 AI (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 AI (t) has a peak amplitude at an unknown code phase shift value t=pI ; (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 AM (t) representing a timing relationship between the composite signal and the reference signal; (4) determining a nominal peak amplitude AM (pM) and the corresponding code phase shift value t=pM of the second correlation function; (5) determining a sequence of U early code phase shift values eI,i <
pI (i=1, . . . , U;
U≧
1) for the first correlation function AI (t) for which the code phase shift amplitude ratios AI (eI,i)/AI (pI)=rI,e,i have selected values;(6) determining a sequence of U early code phase shift values eM,i <
pM (i=1, . . . , U) for the second correlation function AM (t) for which the code phase shift amplitude ratios AM (eM,i)/AM (pM)=rM,e,i have selected values;(7) determining a sequence of V late code phase shift values lI,j >
pI (j =1, . . . , V;
U+V≧
2) for the first correlation function AI (t) for which the code phase shift amplitude ratios AI (lI,j)/AI (pI)=rI,e,j have selected values;(8) determining a sequence of V late code phase shift values lM,j >
pM (j=1, . . . , V) for the second correlation function AM (t) for which the code phase shift amplitude ratios AM (lM,j)/AM (pM)=rM,l,j have selected values;(9) forming a sequence of U code phase shift differences defined by the relations ye,i =(pM -eM,i)-(pI -eI,i) for i=1, . . . , U; (10) forming a sequence Of V code phase shift differences defined by the relations yl,j =(pM -lM,j)-(pI -lI,j) for j=1, . . . , V; (11) determining the difference in punctual code phase shift between the first and second correlation functions by the relation
space="preserve" listing-type="equation">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 pM -pI from an apparent time of arrival of the composite code phase SATPS signal to redetermine the time of arrival of this signal. - View Dependent Claims (12)
-
-
13. 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 AI (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 AI (t) has a peak amplitude at an unknown code phase shift value t=pI ; (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 AM (t) representing a timing relationship between the composite signal and the reference signal; (4) determining a nominal peak amplitude AM (pM) and the corresponding code phase shift value t=pM of the second correlation function; (5) determining a sequence of U early code phase shift values eI,j <
pI (i=1, . . . , U;
U≧
1) for the first correlation function AI (t) for which the code phase shift differences pI -eI,i =Δ
I,e,i have selected values, and forming a first sequence of gradient values BI,e,i =(AI (pI)-AI (eI,i))/(pI -eI,i);(6) determining a sequence of U early code phase shift values eM,i <
pM (i=1, . . . , U) for the second correlation function AM (t), for which the code phase shift differences pM -eM,i =Δ
M,e,i have selected values, and forming a second sequence of gradient values BM,e,i =(AM (pM)-AM (eM,i))/(pM -eM,i);(7) forming a sequence of U gradient differences ze,i =BM,e,i -BI,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
space="preserve" listing-type="equation">p.sub.M -p.sub.I =H.sub.e (z.sub.e,1, . . . , z.sub.e,U),where He is a selected function of U variables; and (9) subtracting the difference pM -pI from an apparent time of arrival of the composite code phase SATPS signal to redetermine the time of arrival of this signal. - View Dependent Claims (14)
-
-
15. 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 AI (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 AI (t) has a peak amplitude at an unknown code phase shift value t=pI ; (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 AM (t) representing a timing relationship between the composite signal and the reference signal; (4) determining a nominal peak amplitude AM (pM) and the corresponding code phase shift value t=pM of the second correlation function; (5) determining a sequence of V late code phase shift values lI,j >
pI (j =1, . . . , V;
V≧
1) for the first correlation function AI (t) for which the code phase shift differences pI -lI,j =Δ
I,l,j have selected values, and forming a first sequence of gradient values BI,l,j =(AI (pI)-AI (lI,j))/(pI -lI,j);(6) determining a sequence of V late code phase shift values lM,j >
pM (j=1, . . . , V) for the second correlation function AM (t), for which the code phase shift differences pM -lM,j =Δ
M,l,j have selected values, and forming a second sequence of gradient values BM,l,j =(AM (pM)-AM (lM,j))/(pM -lM,j);(7) forming a sequence of V gradient differences zl,j =BM,l,j -BI,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
space="preserve" listing-type="equation">p.sub.M -p.sub.I =H.sub.l (z.sub.l,1, . . . , z.sub.l,V),where Hl is a selected function of V variables; and (9) subtracting the difference pM -pI from an apparent time of arrival of the composite code phase SATPS signal to redetermine the time of arrival of this signal. - View Dependent Claims (16, 22)
-
-
17. 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 AI (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 AI (t) has a peak amplitude at an unknown code phase shift value t=pI ; (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 AM (t) representing a timing relationship between the composite signal and the reference signal; (4) determining a nominal peak amplitude AM (pM) and the corresponding code phase shift value t=pM of the second correlation function; (5) determining a sequence of U early code phase shift values eI,i <
pI (i=1, . . . , U;
U≧
1) for the first correlation function AI (t) for which the code phase shift differences pI -eI,i =Δ
I,e,i have selected values, and forming a first sequence of gradient values BI,e,i =(AI (pI)-AI (eI,i))/(pI -eI,i);(6) determining a sequence of U early code phase shift values eM,i <
pM (i=1, . . . , U) for the second correlation function AM (t) for which the code phase shift differences pM -eM,i =Δ
M,e,i have selected values, and forming a second sequence of gradient values BM,e,i =(AM (pM)-AM (eM,i))/(pM -eM,i);(7) determining a sequence of V late code phase shift values lI,j >
pI (j =1, . . . , V;
U+V≧
2) for the first correlation function AI (t) for which the code phase shift pI -eI,j =Δ
I,e,j have selected values and forming a first sequence of gradient values BI,l,j =(AI (pI)-AI (lI,j))/(pI -lI,j);(8) determining a sequence of V late code phase shift values lM,j >
pM (j=1, . . . , V) for the second correlation function AM (t) for which the code phase shift differences pM -lM,j =Δ
M,l,j have selected values, and forming a second sequence of gradient values BM,l,j =(AM (pM)-AM (lM,j))/(pM -lM,j);(9) forming a sequence of U gradient differences ze,i =BM,e,i -BI,e,i for i=1, . . . , U; (10) forming a sequence of V gradient differences ze,j =BM,e,j -BI,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
space="preserve" listing-type="equation">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 pM -pI from an apparent time of arrival of the composite code phase SATPS signal to redetermine the time of arrival of this signal. - View Dependent Claims (18, 24)
-
-
19. 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 AI (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 AI (t) has a peak amplitude at an unknown code phase shift value t=pI ; (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 AM (t) representing a timing relationship between the composite signal and the reference signal; (4) determining a nominal peak amplitude AM (pM) and the corresponding code phase shift value t=pM of the second correlation function; (5) determining a sequence of U early code phase shift values eI,i <
pI (i=1, . . . , U;
U≧
1) for the first correlation function AI (t) for which the correlation amplitude ratios rI,e,i =AI (eI,i)/AI (pI) have selected values, and forming a first sequence of gradient values BI,e,i =(AI (pI)-AI (eI,i))/(pI -eI,i);(6) determining a sequence of U early code phase shift values eM,i <
pM (i=1, . . . , U) for the second correlation function AM (t), for which the correlation amplitude ratios rM,e,i =AM (eM,i)/AM (pM) have selected values, and forming a second sequence of gradient values BM,e,i =(AM (pM) -AM (eM,i))/(pM -eM,i);(7) forming a sequence of U gradient differences ze,i =BM,e,i -BI,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
space="preserve" listing-type="equation">p.sub.M -p.sub.I =K.sub.e (z.sub.e,1, . . . , z.sub.e,U),where Ke is a selected function of U variables; and (9) subtracting the difference pM -pI from an apparent time of arrival of the composite code phase SATPS signal to redetermine the time of arrival of this signal. - View Dependent Claims (20)
-
-
21. 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 AI (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 AI (t) has a peak amplitude at an unknown code phase shift value t=PI ; (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 AM (t) representing a timing relationship between the composite signal and the reference signal; (4) determining a nominal peak amplitude AM (pM) and the corresponding code phase shift value t=pM of the second correlation function; (5) determining a sequence of V late code phase shift values li,j >
pI (j =1, . . . , V;
V≧
1) for the first correlation function AI (t.sub.), for which the correlation amplitude ratios rI,l,j =AI (lI,j)/AI (pI) have selected values, and forming a sequence of gradient values BI,l,j =(AI (pI)-AI (lI,j))/(pI -lI,j);(6) determining a sequence of V late code phase shift values lM,j >
pM (j=1, . . . , V) for the second correlation function AM (t), for which the correlation amplitude ratios rM,l,j =AM (lM,l)/AM (pM) have selected values, and forming a sequence of gradient values BM,l,j =(AM (pM)-AM (lM,j))/(pM -lM,j);(7) forming a sequence of V gradient differences zl,j =BM,l,j -BI,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
space="preserve" listing-type="equation">p.sub.M -p.sub.I =K.sub.l (z.sub.l,1, . . . , z.sub.l,V),where Kl is a selected function of V variables; and (9) subtracting the difference pM -pI from an apparent time of arrival of the composite code phase SATPS signal to redetermine the time of arrival of this signal.
-
-
23. 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 AI (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 AI (t) has a peak amplitude at an unknown code phase shift value t=pI ; (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 AM (t) representing a timing relationship between the composite signal and the reference signal; (4) determining a nominal peak amplitude AM (pM) and the corresponding code phase shift value t=pM of the second correlation function; (5) determining a sequence of U early code phase shift values eI,i <
pI (i=1, . . . , U;
U≧
1) for the first correlation function AI (t) for which the correlation amplitude ratios rI,e,i =AI (eI,i)/AI (pI) have selected values, and forming a first sequence of gradient values BI,e,i =(AI (pI)-AI (eI,i))/(pI -eI,i);(6) determining a sequence of U early code phase shift values eM,i <
pM (i=1, . . . , U) for the second correlation function AM (t) for which the correlation amplitude ratios rM,e,i =AM (eM,i)/AM (pM) have selected values, and forming a second sequence of gradient values BM,e,i =(AM (pM) -AM (eM,i))/(pM -eM,i);(7) determining a sequence of V late code phase shift values lI,j >
pI (j =1, . . . , V;
U+V≧
1) for the first correlation function AI (t) for which the correlation amplitude ratios rI,l,j =AI (lI,j)/AI (pI) have selected values and forming a sequence of gradient values BI,l,j =(AI (pI)-AI (lI,j))/(pI -lI,j);(8) determining a sequence of V late code phase shift values lM,j >
pM (j=1, . . . , V) for the second correlation function AM (t) for which the correlation amplitude ratios rM,l,j =AM (lM,l)/AM (pM) have selected values, and forming a sequence of gradient values BM,l,j =(AM (pM)-AM (lM,j))/(pM -lM,j);(9) forming a sequence of U gradient differences ze,i =BM,e,i -BI,e,i for i=1, . . . , U; (10) forming a sequence of V gradient differences zl,j =BM,l,j -BI,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
space="preserve" listing-type="equation">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 pM -pI from an apparent time of arrival of the composite code phase SATPS signal to redetermine the time of arrival of this signal.
-
-
25. 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 Sref (t) and generating an in-phase reference signal component Sref,in-phase (t) and a quadrature reference signal component Sref,quad (t) from this reference signal, where the reference signal is a digital signal with a timing cycle of selected length, and where AI (t) has a peak amplitude at an unknown code phase shift value t=pI ; receiving a composite signal Scomp (t), consisting of a preferred, interference-free signal distorted by at least one interfering signal, and generating an in-phase reference signal component Scomp,in-phase (t) and a quadrature reference signal component Scomp,quad (t) from this composite signal; generating a first correlation function AI,in-phase (t) representing a timing relationship between the signal Sref,in-phase (t) and the signal Scomp,in-phase (t); generating a second correlation function AM,in-phase (t) representing a timing relationship between the signal Sref,in-phase (t) and the signal Scomp,in-phase (t); generating a third correlation function AI,quad (t) representing a timing relationship between the signal Sref,quad (t) and the signal Scomp,quad (t); generating a fourth correlation function AM,quad (t) representing a timing relationship between the signal Sref,quad (t) and the signal Scomp,quad (t); generating a first combined correlation function
space="preserve" listing-type="equation">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
space="preserve" listing-type="equation">A.sub.M (t)=[(A.sub.M,in-phase (t)).sup.2 +(A.sub.M,quad (t)).sup.2 ].sup.1/2 ; anddetermining a nominal peak amplitude AI (pI) and the corresponding code phase shift value t=pI of the first combined correlation function; determining a nominal peak amplitude AM (pM) and the corresponding code phase shift value t=pM of the first combined correlation function; determining a sequence of U early code phase shift values eI,i <
pI (i=1, . . . , U;
U≧
1) for the first correlation function AI (t) for which the code phase shift differences pI -eI,i =Δ
I,e,i have selected values;determining a sequence of U early code phase shift values eM,i <
pM (i =1, . . . , U) for the second correlation function AM (t) for which the code phase shift differences pM -eM,i =Δ
M,e,i have selected values;forming a sequence of U correlation amplitude ratios defined by the relations xe,i =(AM (eM,i)/AM (pM))-(AI (eI,i)/AI (pI)) for i=1, . . . , U; and determining the difference in punctual code phase shift between the first and second correlation functions by the relation
space="preserve" listing-type="equation">p.sub.M -p.sub.I =F.sub.e (x.sub.e,1, x.sub.e,2, . . . , x.sub.e,U),where Fe is a selected function of U variables.
-
-
26. 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 Scomp (t), consisting of a preferred, interference-free signal distorted by at least one interfering signal, and generating an in-phase reference signal component Scomp,in-phase (t) and a quadrature reference signal component Scomp,quad (t) from this composite signal; generating a first correlation function AI,in-phase (t) representing a timing relationship between the signal Sref,in-phase (t) and the signal Scomp,in-phase (t); generating a second correlation function AM,in-phase (t) representing a timing relationship between the signal Sref,in-phase (t) and the signal Scomp,in-phase (t); generating a third correlation function AI,quad (t) representing a timing relationship between the signal Sref,quad (t) and the signal Scomp,quad (t); generating a fourth correlation function AM,quad (t) representing a timing relationship between the signal Sref,quad (t) and the signal Scomp,quad (t); generating a first combined correlation function
space="preserve" listing-type="equation">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
space="preserve" listing-type="equation">A.sub.M (t)=[(A.sub.M,in-phase (t)).sup.2 +(A.sub.M,quad (t)).sup.2 ].sup.1/2 ; anddetermining a nominal peak amplitude AI (pI) and the corresponding code phase shift value t=pI of the first combined correlation function; determining a nominal peak amplitude AM (pM) and the corresponding code phase shift value t=pM of the first combined correlation function; determining a sequence of V late code phase shift values lI,j >
pI (j=1, . . . , V;
V≧
1) for the first correlation function AI (t) for which the code phase shift differences pI -lI,j =Δ
I,l,j have selected values;determining a sequence of V late code phase shift values lM,j >
pM (j=1, . . . , V) for the second correlation function AM (t) for which the code phase shift differences pM -lM,i =Δ
M,l,j have selected values;forming a sequence of V correlation amplitude ratios defined by the relations xl,i =(AM (lM,j)/AM (pM))-(AI (lI,j)/AI (pI)) for j=1, . . . , V; determining the difference in punctual code phase shift between the first and second correlation functions by the relation
space="preserve" listing-type="equation">p.sub.M -p.sub.I =F.sub.l (x.sub.l,1, x.sub.l,2, . . . , x.sub.l,V),where Fl is a selected function of V variables; and subtracting the difference pM -pI from an apparent, time of arrival of the composite code phase SATPS signal to redetermine the time of arrival of this signal.
-
-
27. 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 Sref (t) and generating an in-phase reference signal component Sref,in-phase (t) and a quadrature reference signal component Sref,quad (t) from this reference signal, where the reference signal is a digital signal with a timing cycle of selected length, and where AI (t) has a peak amplitude at an unknown code phase shift value t=pI ; receiving a composite signal Scomp (t), consisting of a preferred, interference-free signal distorted by at least one interfering signal, and generating an in-phase reference signal component Scomp,in-phase (t) and a quadrature reference signal component Scomp,quad (t) from this composite signal; generating a first correlation function AI,in-phase (t) representing a timing relationship between the signal Sref,in-phase (t) and the signal Scomp,in-phase (t); generating a second correlation function AM,in-phase (t) representing a timing relationship between the signal Sref,in-phase (t) and the signal Scomp,in-phase (t); generating a third correlation function AI,quad (t) representing a timing relationship between the signal Sref,quad (t) and the signal Scomp,quad (t); generating a fourth correlation function AM,quad (t) representing a timing relationship between the signal Sref,quad (t) and the signal Scomp,quad (t); generating a first combined correlation function
space="preserve" listing-type="equation">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
space="preserve" listing-type="equation">A.sub.M (t)=[(A.sub.M,in-phase (t)).sup.2 +(A.sub.M,quad (t)).sup.2 ].sup.1/2 ; anddetermining a nominal peak amplitude AI (pI) and the corresponding code phase shift value t=pI of the first combined correlation function; determining a nominal peak amplitude AM (pM) and the corresponding code phase shift value t=pM of the first combined correlation function; determining a sequence of U early code phase shift values eI,i <
pI (i=1, . . . , U;
U≧
1) for the first correlation function AI (t) for which the code phase shift amplitude ratios AI (eI,i)/AI (pI)=rI,e,i have selected values;determining a sequence of U early code phase shift values eM,i <
pM (i =1, . . . , U) for the second correlation function AM (t) for which the code phase shift amplitude ratios AM (eM,i)/AM (pM)=rM,e,i have selected values;forming a sequence of U code phase shift differences defined by the relations ye,i =(pM -eM,i)-(pI -eI,i) for i=1, . . . , U; and determining the difference in punctual code phase shift between the first and second correlation functions by the relation
space="preserve" listing-type="equation">p.sub.M -p.sub.I =G.sub.e (y.sub.e,1, y.sub.e,2, . . . , y.sub.e,U),where Ge is a selected function of U variables.
-
-
28. 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 Sref (t) and generating an in-phase reference signal component Sref,in-phase (t) and a quadrature reference signal component Sref,quad (t) from this reference signal, where the reference signal is a digital signal with a timing cycle of selected length, and where AI (t) has a peak amplitude at an unknown code phase shift value t=pI ; receiving a composite signal Scomp (t), consisting of a preferred, interference-free signal distorted by at least one interfering signal, and generating an in-phase reference signal component Scomp,in-phase (t) and a quadrature reference signal component Scomp,quad (t) from this composite signal; generating a first correlation function AI,in-phase (t) representing a timing relationship between the signal Sref,in-phase (t) and the signal Scomp,in-phase (t); generating a second correlation function AM,in-phase (t) representing a timing relationship between the signal Sref,in-phase (t) and the signal Scomp,in-phase (t); generating a third correlation function AI,quad (t) representing a timing relationship between the signal Sref,quad (t) and the signal Scomp,quad (t); generating a fourth correlation function AM,quad (t) representing a timing relationship between the signal Sref,quad (t) and the signal Scomp,quad (t); generating a first combined correlation function
space="preserve" listing-type="equation">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
space="preserve" listing-type="equation">A.sub.M (t)=[(A.sub.M,in-phase (t)).sup.2 +(A.sub.M,quad (t)).sup.2 ].sup.1/2 ; anddetermining a nominal peak amplitude AI (pI) and the corresponding code phase shift value t=pI of the first combined correlation function; determining a nominal peak amplitude AM (pM) and the corresponding code phase shift value t=pM of the first combined correlation function; determining a sequence of V late code phase shift values lI,j >
pI (j=1, . . . , V;
V≧
1) for the first correlation function AI (t) for which the code phase shift amplitude ratios AI (lI,j)/AI (pI)=rI,e,j have selected values;determining a sequence of V late code phase shift values lM,j >
pM (j=1, . . . , V) for the second correlation function AM (t) for which the code phase shift amplitude ratios AM (lM,j)/AM (pM)=rM,l,j have selected values;forming a sequence of V code phase shift differences defined by the relations yl,j =(pM -lM,j)-(pI -lI,j) for j=1, . . . , V; and determining the difference in punctual code phase shift between the first and second correlation functions by the relation
space="preserve" listing-type="equation">p.sub.M -p.sub.I =G.sub.l (y.sub.l,1, y.sub.l,2, . . . , y.sub.l,V),where Gl is a selected function of V variables.
-
Specification