US5740048A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and apparatus for GPS positioning, filtering and integration
Assignee: Individual
•
Filing: 1992-08-07
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Granted: 1998-04-14
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Expires: 2012-08-07
Abstract
Abstract A method and apparatus for processing data from a positioning or navigation system, such as global positioning system (GPS) navigation system data. In preferred embodiments, the invention is a method and apparatus for estimating position based on GPS measurements and optionally, measurements from other types of navigation sensors combined with GPS navigation system data. The apparatus of the invention includes a point position estimator (which preferably approximates a maximum likelihood estimator) for processing data from a positioning or navigation system to generate point position estimate data, and a smoothing filter for smoothing the point position estimate data. The smoothing filter can be a linear Kalman filter.
Inventors
- 👤 Jonathan S. Abel
- 👤 James W. Chaffee
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 14:26
CPC Classifications
G; G01; G01S; G01S19/00; G01S19/38; G01S19/39; G01S19/42; G01C; G01C21/00; G01C21/10; G01C21/12; G01C21/16; G01C21/165; G01C21/26; G01C21/28; G01S19/48; G01S19/49; G01S5/00; G01S5/02; G01S5/0294
Claims Analysis
Total Claims: 36
Claim 1
Independent Claim
41 words
A two-stage filter for processing navigation data, including: a navigation processor for computing point position and/or bias estimates from input pseudorange data; and a smoothing filter for receiving and smoothing the point position and/or bias estimates output from the navigation processor.
Claim 2
Dependent Claim
41 words
A two-stage filter for processing navigation data, including: a navigation processor for computing point position and/or bias estimates from input pseudorange data; and a smoothing filter for receiving and smoothing the point position and/or bias estimates output from the navigation processor.
Claim 3
Dependent Claim
21 words
The filter of claim 1, wherein the smoothing filter includes two separate filters for separately smoothing point position and bias estimates.
Claim 4
Dependent Claim
30 words
The filter of claim 1, wherein the smoothing filter smooths point position and bias estimates in parallel, in a manner in which cross-correlation between position and bias estimates is determined.
Claim 5
Dependent Claim
14 words
The filter of claim 1, wherein the smoothing filter is a constant-gain Kalman filter.
Claim 6
Dependent Claim
14 words
The filter of claim 1, wherein the smoothing filter is a time-varying-gain Kalman filter.
Claim 7
Dependent Claim
14 words
The filter of claim 1, wherein the smoothing filter is a linear smoothing filter.
Claim 8
Dependent Claim
26 words
The filter of claim 1, wherein the navigation processor receives and processes externally measured bias data, to improve quality of the point position and/or bias estimates.
Claim 9
Dependent Claim
23 words
The filter of claim 1, wherein the navigation processor computes measured bias data from the input pseudorange data, by filtering point bias estimates.
Claim 10
Dependent Claim
17 words
The filter of claim 1, wherein the navigation processor computes point position estimates based on pseudorange differences.
Claim 11
Dependent Claim
36 words
The filter of claim 1, wherein the navigation processor computes point position and/or bias estimates by minimizing or approximately minimizing a weighted norm of one of a pseudorange equation error and a pseudorange difference equation error.
Claim 12
Dependent Claim
34 words
The filter of claim 10, wherein the navigation processor performs approximate minimization using a divide and conquer method wherein estimates based on subsets of available pseudorange data are combined to form a unified estimate.
Claim 13
Dependent Claim
36 words
The filter of claim 10, wherein the navigation processor performs approximate minimization using a Lagrange multiplier technique wherein an optimum position is a function of a range parameter, wherein the range parameter satisfies a norm constraint.
Claim 14
Dependent Claim
22 words
The filter of claim 12, including means for computing the range parameter using a singular value decomposition method satisfying the norm constraint.
Claim 15
Dependent Claim
38 words
The filter of claim 1, wherein externally available point estimates of position, velocity, and/or acceleration coordinates are applied to the smoothing filter along with the navigation processor output to improve accuracy of the output of said smoothing filter.
Claim 16
Dependent Claim
18 words
The filter of claim 14, wherein the externally available point estimates are based on inertial navigation system data.
Claim 17
Dependent Claim
17 words
The filter of claim 14, wherein the externally available point estimates are based on LORAN time differences.
Claim 18
Dependent Claim
16 words
The filter of claim 14, wherein the externally available point estimates are based on transponder ranges.
Claim 19
Dependent Claim
16 words
The filter of claim 14, wherein the externally available point estimates are based on altimeter data.
Claim 20
Dependent Claim
17 words
The filter of claim 14, wherein the externally available point estimates are based on dead reckoning data.
Claim 21
Dependent Claim
27 words
The filter of claim 1, wherein the navigation processor receives and processes externally measured clock bias data to improve quality of the point position and/or bias estimates.
Claim 22
Dependent Claim
25 words
The filter of claim 20, wherein the externally measured clock bias data are formed by filtering point bias estimates computed from the input pseudorange data.
Claim 23
Dependent Claim
32 words
The filter of claim 20, wherein an externally measured position coordinate is used by the navigation processor to improve accuracy of the point position and/or bias estimates output from the navigation processor.
Claim 24
Dependent Claim
34 words
The filter of claim 22, wherein a gauge of the accuracy of a measured position coordinate is used to weight the contribution of the measured position coordinate to the point position and/or bias estimates.
Claim 25
Dependent Claim
26 words
The filter of claim 1, wherein available differential GPS corrections are used by the navigation processor to correct a pseudorange difference part of the pseudorange data.
Claim 26
Dependent Claim
26 words
The filter of claim 1, wherein the navigation processor computes estimates of covariance of the point position and/or bias estimates for use in the smoothing filter.
Claim 27
Dependent Claim
34 words
The filter of claim 1, wherein an externally available position coordinate is used to constrain the navigation processor output, thereby improving quality of the point position and/or bias estimates output from the navigation processor.
Claim 28
Dependent Claim
37 words
A two-stage filter for processing navigation data, including: a navigation processor for computing point position estimates from input range data; and a smoothing filter for receiving and smoothing the point position estimates output from the navigation processor.
Claim 29
Dependent Claim
37 words
A two-stage filter for processing navigation data, including: a navigation processor for computing point position estimates from input range data; and a smoothing filter for receiving and smoothing the point position estimates output from the navigation processor.
Claim 30
Dependent Claim
38 words
A two-stage filter for processing navigation data, including: a navigation processor for computing point position estimates from input range difference data; and a smoothing filter for receiving and smoothing the point position estimates output from the navigation processor.
Claim 31
Dependent Claim
38 words
A two-stage filter for processing navigation data, including: a navigation processor for computing point position estimates from input range difference data; and a smoothing filter for receiving and smoothing the point position estimates output from the navigation processor.
Claim 32
Independent Claim
33 words
A method for processing navigation data, including the steps of: (a) computing point position and/or bias estimates from input pseudorange data; and (b) after step (a), smoothing the point position and/or bias estimates.
Claim 33
Independent Claim
33 words
A method for processing navigation data, including the steps of: (a) computing point position and/or bias estimates from input pseudorange data; and (b) after step (a), smoothing the point position and/or bias estimates.
Claim 34
Dependent Claim
23 words
The method of claim 29, wherein step (b) includes the step of smoothing the point position and/or bias estimates in a Kalman filter.
Claim 35
Dependent Claim
30 words
The method of claim 29, wherein step (a) includes the step of approximately minimizing a weighted norm of one of a pseudorange equation error and a pseudorange difference equation error.
Claim 36
Dependent Claim
24 words
The method of claim 29, wherein step (a) includes the step of computing an estimate of covariance of the point position and/or bias estimates.
References Cited (Backward Citations)
US4232313A
Cited
US4894662A
Cited
US4589610A
Cited
US4646096A
Cited
US4954837A
Cited
US5062123A
Cited
US5153599A
Cited
US5216611A
Cited
US5184304A
Cited
US5202829A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2001-04-13 | 2001-10-13 | 2002-04-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2005-04-13 | 2005-10-13 | 2006-04-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2009-04-13 | 2009-10-13 | 2010-04-14 | $7700.00 | Window Closed / Lapsed |