Method and apparatus for improving the accuracy of relative position estimates in a satellite-based navigation system
First Claim
Patent Images
1. A method for determining the relative position between a first receiver and a second receiver using a satellite-based navigation system utilizing a constellation of navigation satellites and a communication link between the first receiver and the second receiver, the method comprising the steps of:
- receiving, from a first plurality of satellites of the constellation of navigation satellites, a first plurality of navigation signals at the first receiver;
receiving, from a second plurality of satellites of the constellation of navigation satellites, a second plurality of navigation signals at the second receiver;
computing, at the first receiver, a position estimate of the first receiver;
computing, at the second receiver, a position estimate of the second receiver;
transmitting from the second receiver to the first receiver, through the communication link, the second plurality of navigation signals and the position estimate of the second receiver;
computing, at the first receiver, a plurality of satellite positions of the first and second pluralities of satellites;
computing, at the first receiver, a first plurality of unit vectors between the first receiver and the first plurality of satellites;
computing, at the first receiver, a second plurality of unit vectors between the second receiver and the second plurality of satellites;
extracting, at the first receiver, from the first plurality of navigation signals, a first plurality of raw pseudoranges between the first receiver and each of the first plurality of satellites;
extracting, at the first receiver from the second plurality of navigation signals, a second plurality of raw pseudoranges between the second receiver and each of the second plurality of satellites;
computing, at the first receiver, a first plurality of range equivalents of the clock offsets of each of the first plurality of satellites;
computing, at the first receiver, a second plurality of range equivalents of the clock offsets of each of the second plurality of satellites; and
determining a precise relative position between the first receiver and the second receiver from the plurality of satellite positions of the first and second pluralities of satellites, the first and second pluralities of unit vectors, the first and second pluralities of raw pseudoranges, and the first and second pluralities of range equivalents of the clock offsets of each of the first and second pluralities of satellites, respectively.
9 Assignments
0 Petitions
Accused Products
Abstract
The accuracy of relative position estimates between two vehicles, generated using a satellite-based navigation system, is improved by eliminating at an early stage in the calculation process, errors affecting simultaneously both receivers. The standard absolute navigation equations are modified to solve directly for relative position, while avoiding a final step differentiation, thereby providing increased precision.
-
Citations
55 Claims
-
1. A method for determining the relative position between a first receiver and a second receiver using a satellite-based navigation system utilizing a constellation of navigation satellites and a communication link between the first receiver and the second receiver, the method comprising the steps of:
-
receiving, from a first plurality of satellites of the constellation of navigation satellites, a first plurality of navigation signals at the first receiver; receiving, from a second plurality of satellites of the constellation of navigation satellites, a second plurality of navigation signals at the second receiver; computing, at the first receiver, a position estimate of the first receiver; computing, at the second receiver, a position estimate of the second receiver; transmitting from the second receiver to the first receiver, through the communication link, the second plurality of navigation signals and the position estimate of the second receiver; computing, at the first receiver, a plurality of satellite positions of the first and second pluralities of satellites; computing, at the first receiver, a first plurality of unit vectors between the first receiver and the first plurality of satellites; computing, at the first receiver, a second plurality of unit vectors between the second receiver and the second plurality of satellites; extracting, at the first receiver, from the first plurality of navigation signals, a first plurality of raw pseudoranges between the first receiver and each of the first plurality of satellites; extracting, at the first receiver from the second plurality of navigation signals, a second plurality of raw pseudoranges between the second receiver and each of the second plurality of satellites; computing, at the first receiver, a first plurality of range equivalents of the clock offsets of each of the first plurality of satellites; computing, at the first receiver, a second plurality of range equivalents of the clock offsets of each of the second plurality of satellites; and determining a precise relative position between the first receiver and the second receiver from the plurality of satellite positions of the first and second pluralities of satellites, the first and second pluralities of unit vectors, the first and second pluralities of raw pseudoranges, and the first and second pluralities of range equivalents of the clock offsets of each of the first and second pluralities of satellites, respectively. - View Dependent Claims (2, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
-
-
3. A method for computing the relative position between a first receiver and a second receiver using a satellite-based navigation system having a constellation of navigation satellites and a communication link between the first receiver and the second receiver, the method comprising the steps of:
-
receiving, at the first receiver, from a first plurality of satellites of the constellation of navigation satellites, a first plurality of navigation signals; receiving, at the second receiver, from a second plurality of satellites of the constellation of navigation satellites, a second plurality of navigation signals; computing, at the first receiver, a first plurality of unit vectors between the first receiver and the first plurality of satellites; computing, at the second receiver, a second plurality of unit vectors between the second receiver and the second plurality of satellites; computing, at the first receiver, a plurality of satellite positions of the first and second pluralities of satellites; extracting, at the first receiver, from the first plurality of navigation signals, a first plurality of raw pseudoranges between the first receiver and each of the first plurality of satellites; extracting, at the second receiver, from the second plurality of navigation signals, a second plurality of raw pseudoranges between the second receiver and each of the second plurality of satellites; computing, at the first receiver, a first plurality of range equivalents of the clock offsets of each of the first plurality of satellites; computing, at the second receiver, a second plurality of range equivalents of the clock offsets of each of the second plurality of satellites; and transmitting from the second receiver to the first receiver, through the communication link, the second plurality of unit vectors, the second plurality of raw pseudoranges, and the second plurality of range equivalents of the clock offsets of each of the second plurality of satellites; determining a precise relative position between the first receiver and the second receiver from the plurality of satellite positions of the first and second pluralities of satellites, the first and second pluralities of unit vectors, the first and second pluralities of raw pseudoranges, and the first and second pluralities of range equivalents of the clock offsets of each of the first and second plurality of satellites, respectively. - View Dependent Claims (4, 20, 22, 24, 26)
-
-
5. An apparatus for determining the relative position between a first receiver and a second receiver using signals from a satellite-based navigation system utilizing a constellation of navigation satellites, the apparatus comprising:
-
a first receiver for receiving a first plurality of navigation signals from the constellation of navigation satellites; a second receiver for receiving a second plurality of navigation signals from the constellation of navigation satellites; means, coupled to said first receiver and the second receiver, for computing, based upon said first plurality of navigation signals and said second plurality of navigation signals, a first matrix comprising weighted coefficients, a second matrix comprising observable parameters and solving for the relative navigation equation position using said first matrix and said second matrix, where said first matrix of weighted coefficients comprises; where;
##EQU14## where unit vectors are calculated as;
##EQU15## where i and j vary between 1 and n, and 1 and p, respectively, where n represents a number of the first plurality of satellites,where p represents a number of the second plurality of satellites, A1 denotes the position of the first receiver, A2 denotes the position of the second receiver, S1,i denotes the position of an ith satellite in the first plurality of satellites, and S2,j denotes the position of a jth satellite in the second plurality of satellites. - View Dependent Claims (54)
-
-
19. ρ
-
1. i denotes a pseudorange between the first receiver and an ith satellite in the first plurality of satellites,
ρ
2,j denotes a pseudorange between the second receiver and a jth satellite in the second plurality of satellites,e1 denotes a range equivalent for a first receiver clock offset, and e2 denotes a range equivalent for a second receiver clock offset, e1,i denotes a range equivalent of a clock offset of an ith satellite of first plurality of satellites, e2,j denotes a range equivalent of a clock offset of an jth satellite of second plurality of satellites, and where i and j vary between 1 and n, and 1 and p, respectively, where n represents a number of the first plurality of satellites, and where p represents a number of the second plurality of satellites. - View Dependent Claims (21, 23, 25, 27, 30, 33, 36, 39, 42, 45, 48, 51, 55)
-
1. i denotes a pseudorange between the first receiver and an ith satellite in the first plurality of satellites,
-
28. ρ
-
1. i denotes a pseudorange between the first receiver and an ith satellite in the first plurality of satellites,
ρ
2,j denotes a pseudorange between the second receiver and a jth satellite in the second plurality of satellites,e1 denotes a range equivalent for a first receiver clock offset, and e2 denotes a range equivalent for a second receiver clock offset, e1,i denotes a range equivalent of a clock offset of an ith satellite of first plurality of satellites, e2,j denotes a range equivalent of a clock offset of an jth satellite of second plurality of satellites, and where i and j vary between 1 and n, and 1 and p, respectively, where n represents a number of the first plurality of satellites, and where p represents a number of the second plurality of satellites. - View Dependent Claims (31, 34, 37, 40)
-
1. i denotes a pseudorange between the first receiver and an ith satellite in the first plurality of satellites,
-
29. An apparatus for determining the relative position between two points, comprising:
-
a first receiver located at a first point, for receiving signals from a first plurality of satellites of a satellite-based navigation system having a constellation of navigation satellites; a second receiver located at a second point, for receiving signals from a second plurality of satellites of the satellite-based navigation system having a constellation of navigation satellites; a communication link between the first receiver and the second receiver, wherein the first receiver further includes; means for receiving, from a first plurality of satellites of the constellation of navigation satellites, a first plurality of navigation signals at the first receiver; means for computing a position estimate of the first receiver; means for computing a plurality of satellite positions of the first and second pluralities of satellites; means for transmitting from the first receiver to the second receiver, through the communication link, the first plurality of navigation signals and the position estimate of the first receiver, and wherein the second receiver further includes; means for receiving, from a second plurality of satellites of the constellation of navigation satellites, a second plurality of navigation signals at the second receiver; means for computing a position estimate of the second receiver; means for computing a first plurality of unit vectors between the first receiver and each of the first plurality of satellites; means for computing a second plurality of unit vectors between the second receiver and each of the second plurality of satellites; means for extracting from the first plurality of navigation signals, a first plurality of raw pseudoranges between the first receiver and each of the first plurality of satellites; means for extracting from the second plurality of navigation signals, a second plurality of raw pseudoranges between the second receiver and each of the second plurality of satellites; means for computing a first plurality of range equivalents of the clock offsets of each of the first plurality of satellites; means for computing a second plurality of range equivalents of the clock offsets of each of the second plurality of satellites; and means for determining a precise relative position between the first receiver and the second receiver from the pluralities of satellites, the first and second pluralities of unit vectors, the first and second pluralities of raw pseudoranges, and the first and second pluralities of range equivalents of the clock offsets of each of the first and second pluralities of satellites, respectively. - View Dependent Claims (32, 35, 38, 41, 44, 47, 50)
-
-
43. A apparatus for computing the relative position between two points, comprising:
-
a first receiver located at a first point, for receiving signals from a satellite-based navigation system having a constellation of navigation satellites; a second receiver located at a second point, for receiving signals from a satellite-based navigation system having a constellation of navigation satellites; and a communication link between the first receiver and the second receiver, wherein the first receiver includes; means for receiving, from a first plurality of satellites of the constellation of navigation satellites, a first plurality of navigation signals; means for computing a first plurality of unit vectors between the first receiver and each of the first plurality of satellites; means for computing a plurality of satellite positions of the first and second pluralities of satellites; means for extracting from the first plurality of navigation signals, a first plurality of raw pseudoranges between the first receiver and each of the first plurality of satellites; means for computing a first plurality of range equivalents of the clock offsets of each of the first plurality of satellites; means for transmitting from the first receiver to the second receiver, through the communication link, the first plurality of unit vectors, the first plurality of raw pseudoranges, and the first plurality of range equivalents of the clock offsets of each of the first plurality of satellites, and wherein the second receiver includes; means for receiving, from a second plurality of satellites of the constellation of navigation satellites, a second plurality of navigation signals; means for computing a second plurality of unit vectors between the second receiver and each of the second plurality of satellites;
.means for extracting from the second plurality of navigation signals, a second plurality of raw pseudoranges between the first receiver and each of the second plurality of satellites; means for computing a second plurality of range equivalents of the clock offsets of each of the second plurality of satellites; and means for determining a precise relative position between the first receiver and the second receiver from the plurality of satellite positions of the first and second pluralities of satellites, the first and second pluralities of unit vectors, the first and second pluralities of raw pseudoranges, and the first and second pluralities of range equivalents of the clock offsets of each of the first and second pluralities of satellites, respectively. - View Dependent Claims (46, 49, 52)
-
-
53. ρ
-
2. j denotes a pseudorange between the second receiver and a jth satellite in the second plurality of satellites,
e1 denotes a range equivalent for a first receiver clock offset, and e2 denotes a range equivalent for a second receiver clock offset, e1,i denotes a range equivalent of a clock offset of an ith satellite of first plurality of satellites, e2,j denotes a range equivalent of a clock offset of an jth satellite of second plurality of satellites, and where i and j vary between 1 and n, and 1 and p, respectively, where n represents a number of the first plurality of satellites, and where p represents a number of the second plurality of satellites.
-
2. j denotes a pseudorange between the second receiver and a jth satellite in the second plurality of satellites,
Specification