US4642647A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Signal generator for radio navigation system
Assignee: Northrop Grumman Guidance and Electronics Co Inc
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Filing: 1983-08-29
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Granted: 1987-02-10
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Expires: 2003-08-29
Abstract
Abstract An improved signal generator and method for radio navigation in accordance with systems of the type in which location is determined in accordance with radio fixings with respect to multiple points of reference, each of such points providing a coded transmission. Multiple coded bit sequences are stored in an adddressable read only memory. Phantom signals comprising a plurality of coded sequences are generated by addressing the memory in accordance with preselected sequences. Further, predetermined phase shifts are applied to the coded sequences to facilitate signal detection and associated computational processes.
Inventors
- 👤 Mark A. Sturza
- 👤 Wayne L. Knitter
- 👤 Yi-Zen Wu
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 03:55
CPC Classifications
G; G01; G01S; G01S19/00; G01S19/01; G01S19/13; G01S19/24; G01S19/30
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
111 words
A multiple code generator for use in a radio navigation system of the type wherein location is determined in accordance with multiple spatially-distributed radio frequency signal fixings, each of said signal fixings comprising a radio frequency signal of preselected coding, said code generator comprising, in combination: a. a read only memory for storing a plurality of bit sequences, each of said sequences comprising a predetermined code of said navigation system; b. means coupled to said read only memory for accessing preselected bit sequences; c. means for applying a predetermined bit rate and phase shift to said sequences, said means including a counter; and d. means for outputting said preselected bit sequences.
Claim 2
Dependent Claim
111 words
A multiple code generator for use in a radio navigation system of the type wherein location is determined in accordance with multiple spatially-distributed radio frequency signal fixings, each of said signal fixings comprising a radio frequency signal of preselected coding, said code generator comprising, in combination: a. a read only memory for storing a plurality of bit sequences, each of said sequences comprising a predetermined code of said navigation system; b. means coupled to said read only memory for accessing preselected bit sequences; c. means for applying a predetermined bit rate and phase shift to said sequences, said means including a counter; and d. means for outputting said preselected bit sequences.
Claim 3
Dependent Claim
28 words
A multiple code generator as defined in claim 1 wherein said means for applying a predetermined bit rate and phase shift further includes means for presetting said counter.
Claim 4
Dependent Claim
34 words
A multiple code generator as defined in claim 2 wherein the information applied to said counter exceeds the information applied to said read only memory so that fractional code phase shifts may be attained.
Claim 5
Independent Claim
79 words
A method for generating multiple local replica codes for use in a radio navigation system of the GPS type comprising the steps of: a. storing a plurality of coded bit sequences in a table in a read only memory wherein each of said sequences is a pseudo-noise sequence, b. accessing preselected bit sequences, c. outputting said preselected bit sequences under the control of a counter and presetting said counter so that said sequences are output with predetermined phase shifts.
Claim 6
Independent Claim
79 words
A method for generating multiple local replica codes for use in a radio navigation system of the GPS type comprising the steps of: a. storing a plurality of coded bit sequences in a table in a read only memory wherein each of said sequences is a pseudo-noise sequence, b. accessing preselected bit sequences, c. outputting said preselected bit sequences under the control of a counter and presetting said counter so that said sequences are output with predetermined phase shifts.
Claim 7
Dependent Claim
30 words
A method as defined in claim 4 including the step of arranging said counter so that the phases of said sequences can be shifted by a fraction of a bit.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1990-02-09 | 1990-08-11 | 1991-02-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-02-09 | 1994-08-11 | 1995-02-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-02-09 | 1998-08-11 | 1999-02-10 | $7700.00 | Window Closed / Lapsed |