US5036329A
Expired / Lapsed
US
⏱️ 0.0 years remaining
GPS satellite signal tracking method for GPS receivers
Assignee: Pioneer Corp
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Filing: 1990-08-28
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Granted: 1991-07-30
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Expires: 2010-08-28
Abstract
Abstract When reception of satellite signals is lost, for example, one minute, satellite signals are searched firstly in accordance with a narrow-band search mode by varying a search frequency within a range of Doppler frequency shift estimated by a moving speed of a GPS receiver, for example, ±600 Hz for a vehicle-mounted GPS receiver, for a duration which is determined by dividing a capture range (±150 Hz) by a rate of Doppler shift (40 Hz/sec) and, secondly, switching over the search mode from the narrow-band search to a wide-band search if recapturing of the satellite signal is failed through the narrow-band search within the predetermined duration (3 minutes 45 seconds) for recapturing the lost satellite signals, and thereby providing a expeditious two-step search method for decreasing a time required in recapturing the lost satellite signals.
Inventors
- 👤 Hitoshi Ando
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 12:40
CPC Classifications
G; G01; G01S; G01S19/00; G01S19/01; G01S19/13; G01S19/24; G01S19/29
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
73 words
A satellite signal tracking method for a GPS receiver comprising the steps of: performing a narrow-band search for satellite signals when the satellite signal from a GPS satellite being tracked is interrupted for more than a specified period of time; and switching over the narrow-band search to a wide-band search for searching the satellite signals when the narrow-band search fails to recapture any of the satellite signals within a predetermined duration of time.
Claim 2
Dependent Claim
73 words
A satellite signal tracking method for a GPS receiver comprising the steps of: performing a narrow-band search for satellite signals when the satellite signal from a GPS satellite being tracked is interrupted for more than a specified period of time; and switching over the narrow-band search to a wide-band search for searching the satellite signals when the narrow-band search fails to recapture any of the satellite signals within a predetermined duration of time.
Claim 3
Dependent Claim
57 words
A satellite signal tracking method for a GPS receiver as claimed in claim 1, wherein said narrow-band search is performed by changing a PLL search frequency in succession within a range of Doppler frequency shift which is predicted from a moving speed of the GPS receiver and centering on the last reception frequency of the satellite signal.
Claim 4
Dependent Claim
42 words
A satellite signal tracking method for a GPS receiver as claimed in claim 1, wherein said narrow-band search being performed in the duration determined by dividing a PLL capture range by the rate of Doppler shift of the receiving satellite signal frequency.
Claim 5
Dependent Claim
36 words
A satellite signal tracking method for a GPS receiver as claimed in claim 1, wherein said wide-band search is performed within the maximum range of the overall receiving frequency shift to search for the satellite signals.
Claim 6
Dependent Claim
23 words
A satellite signal tracking method for a GPS receiver as claimed in claim 2, wherein said range of Doppler shift is ±600 Hz.
Claim 7
Dependent Claim
23 words
A satellite signal tracking method for a GPS receiver as claimed in claim 1, wherein said specified period of time is one minute.
Claim 8
Dependent Claim
23 words
A satellite signal tracking method for a GPS receiver as claimed in claim 3, wherein said duration is 3 minutes and 45 seconds.
Claim 9
Dependent Claim
43 words
A satellite signal tracking method for a GPS receiver as claimed in claim 1, wherein said wide-band search is performed by changing the PLL search frequency successively within the maximum range of the overall receiving frequency shift to search for the satellite signals.
Claim 10
Dependent Claim
23 words
A satellite signal tracking method for a GPS receiver as claimed in claim 8, wherein said overall receiving frequency shift is ±8,600 Hz.
References Cited (Backward Citations)
US4578678A
Cited
US4785463A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1994-07-29 | 1995-01-28 | 1995-07-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-07-29 | 1999-01-28 | 1999-07-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-07-29 | 2003-01-28 | 2003-07-30 | $7700.00 | Window Closed / Lapsed |