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 Title: |
US5285472:
System for determining the acquisition of, and frequency compensating, a phase modulated pseudonoise sequence signal
[ Derwent Title ]
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| Country: |
US United States of America
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| Inventor: |
Leonard, Jay F.; Kinnelon, NJ
Paradise, Ronald Y.; Hillsdale, NJ
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| Assignee: |
GEC-Marconi Electronic Systems Corp., Wayne, NJ
other patents from GEC-MARCONI ELECTRONIC SYSTEMS CORP. (217291) (approx. 18)
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| Published / Filed: |
1994-02-08
/ 1993-02-24
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| Application Number: |
US1993000021781
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| IPC Code: |
Advanced:
H04B 1/707;
Core:
more...
IPC-7:
H04K 1/00;
H04L 27/30;
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| U.S. Class: |
Current:
375/150;
375/E01.003;
Original:
375/001;
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| Field of Search: |
375/001
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| Priority Number: |
| 1993-02-24 |
US1993000021781 |
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| Abstract: |
A system which receives a pseudonoise sequence signal quantizes the signal during a fixed interval of time and passes the quantized signal to a plurality of correlation channels. Each of the correlation channels rotates the incoming phase modulation at a different fixed rate to cancel out a corresponding component of offset frequency. The outputs of the correlation channels are examined to determine whether acceptable correlation has been attained and, if so, which channel provides the best frequency compensation.
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| Attorney, Agent or Firm: |
Davis, David L. ;
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| Primary / Asst. Examiners: |
Cangialosi, Salvatore;
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| INPADOC Legal Status: |
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Family Legal Status Report
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| Family: |
Show 6 known family members
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First Claim:
Show all 7 claims |
We claim:
1. In a system where a phase modulated pseudonoise sequence signal is received at a frequency which is within a range of frequencies centered around a nominal carrier frequency, and wherein code elements in the signal occur at a predetermined code chip rate, an arrangement for determining acquisition of the received signal and approximating the received frequency within one of 2K substantially equal subdivisions of said range, where K is an integer, the arrangement comprising:
- means for providing a reference signal at the nominal carrier frequency;
- means for providing a clock signal at a clock frequency corresponding to the code chip rate;
- means for deriving in-phase and quadrature components of the received signal relative to the reference signal;
- means utilizing the clock signal and the in-phase and quadrature components for quantizing the phase of the received signal into 2S sectors, where S is an integer, and providing an S-bit digital signal representative of the quantized phase at a rate corresponding to the clock frequency;
- means for providing K signals each at a respective fixed detection frequency less than said clock frequency, the frequencies of the K signals being related to each other in the ratios of approximately 1, 3, . . . , 2K-1, wherein the K fixed detection frequencies are selected to satisfy the requirement that the range of frequencies within which said received signal appears is approximately 4K times the lowest frequency of said K signals;
- means for providing said pseudonoise sequence in digital form as an ordered sequence of code elements;
- a plurality of 2K correlation channels, each of said correlation channels including:
- a) phase rotation means for providing a phase rotated received signal by changing the quantized phase sector of the received signal at a rate determined by a respective one of the K signals and in a respective one of the additive or subtractive directions, so that between all of the 2K correlation channels each of the K signals is used twice, once in an additive sense and once in a subtractive sense; and
- b) digital correlation means utilizing the provided pseudonoise sequence and the phase rotated received signal for providing a measure of the correlation between the phase rotated received signal and the pseudonoise sequence; and
- discrimination means coupled to receive the correlation measures from said 2K correlation channels for determining the acquisition of the received signal and selecting the correlation channel with the greatest correlation.
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| Background / Summary: |
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| Drawing Descriptions: |
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| Description: |
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| Forward References: |
Show 24 U.S. patent(s) that reference this one
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| Foreign References: |
None
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| Other References: |
Fred E. Nathanson, Radar Design Principles, pp. 421-423, McGraw-Hill, 1969.
J. B. Thomas et al., Counterrotator and Correlator for GPS Receivers, NASA TECH BRIEF, vol. 13, No. 6, Item #148, Jet Propulsion Laboratory, Jun. 1989.
T. K. Meehan et al., Chip Advancer for GPS Receiver, NASA TECH BRIEF, vol. 13, No. 6, Item #147, Jet Propulsion Laboratory, Jun. 1989.
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