Patent USH767H successfully refreshed from Google Patents.
USH767H
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US
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Ranging method and system, especially for radar signal processing for ambiguous range radars
Assignee: United States Department of the Navy
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Filing: 1989-06-29
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Granted: 1990-04-03
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Expires: 2009-06-29
Abstract
Abstract A method and apparatus exploiting the discovery that the cross-correlation of rows of Frank or P4 matrices of a given spacing sum to zero. In a ranging system, such as a radar, pulses are coded according to the rows of a Frank or P4 matrix, transmitted sequentially and each return processed sequentially through a filter matched to one of the coded pulses. (A different preselected filter is used for each return.) The sequence of filters is chosen so that for returns for a given range interval, each filter is matched to the returning pulse, resulting in outputs from the filters representing auto-correlations of the returned pulses. These outputs are time delayed added coherently to form the compressed pulse, and annunciated as a target hit. Should the filters and returns be mismatched, as with ambiguous stationary clutter returns, the outputs of the filters are cross-correlations which, according to said discovery, sum to zero. Thus the invention operates to remove ambiguous range clutter from returns in such a ranging system.
Inventors
- 👤 Frank F. Kretschmer, Jr.
- 👤 Karl R. Gerlach
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 03:27
CPC Classifications
G; G01; G01S; G01S13/00; G01S13/02; G01S13/06; G01S13/08; G01S13/10; G01S13/30; G01S13/26; G01S13/28; G01S13/284; G01S13/288
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
235 words
A method of ranging comprising steps for: transmitting a sequence of coded pulses F 1 , F 2 , . . . F 0 , F 1 , . . . , F N-1 , each of said coded pulses F n , n=0, 1, 2 . . . , N-1, being coded in accordance with the (n+1)th row of a Frank or P4 matrix of dimension N×N; each of said coded pulses being spaced from adjacent ones of said coded pulses by time intervals t 0 , t 1 , . . . , t N-1 , each F n being followed immediately by a corresponding t n , the last N of said time intervals being denominated detection intervals; selecting an integer c from the set whose members are: 0, 1, 2, . . . , N-1; detecting returns of said coded pulses during each of said detection intervals; processing said returns, said step for processing using a plurality of N filters, each filter of said plurality of N filters being matched to a corresponding one of said coded pulses, said step for processing comprising steps for: passing each of said returns detected in each said detection interval t n through a corresponding one of said filters matched to one of said coded pulses F j , j=(N+n-c) mod N; and coherently summing the outputs of said filters generated during said detection intervals.
Claim 2
Independent Claim
235 words
A method of ranging comprising steps for: transmitting a sequence of coded pulses F 1 , F 2 , . . . F 0 , F 1 , . . . , F N-1 , each of said coded pulses F n , n=0, 1, 2 . . . , N-1, being coded in accordance with the (n+1)th row of a Frank or P4 matrix of dimension N×N; each of said coded pulses being spaced from adjacent ones of said coded pulses by time intervals t 0 , t 1 , . . . , t N-1 , each F n being followed immediately by a corresponding t n , the last N of said time intervals being denominated detection intervals; selecting an integer c from the set whose members are: 0, 1, 2, . . . , N-1; detecting returns of said coded pulses during each of said detection intervals; processing said returns, said step for processing using a plurality of N filters, each filter of said plurality of N filters being matched to a corresponding one of said coded pulses, said step for processing comprising steps for: passing each of said returns detected in each said detection interval t n through a corresponding one of said filters matched to one of said coded pulses F j , j=(N+n-c) mod N; and coherently summing the outputs of said filters generated during said detection intervals.
Claim 3
Independent Claim
256 words
An apparatus for ranging, said apparatus comprising: means for transmitting a sequence of coded pulses F 1 , F 2 , . . . , F 0 , F 1 , . . . , F N-1 , each of said coded pulses F n , n=0, 1, 2, . . . , N-1, being coded in accordance with the (n+1)th row of a Frank or P4 matrix of dimension N×N; said means for transmitting being effective to cause each of said coded pulses to be spaced from adjacent ones of said coded pulses by time intervals t 0 , t 1 , . . . , t N-1 , each F n being followed immediately by a corresponding t n , the last N of said time intervals being denominated detection intervals; means for selecting an integer c from the set whose members are: 0, 1, 2, . . . , N-1; means for detecting returns of said coded pulses during each of said detection intervals; means for processing said returns, said means for processing comprising a plurality of N filters, each filter of said plurality of N filters being matched to a corresponding one of said coded pulses, said means for processing further comprising: means for passing each of said returns detected in each said detection interval t n through a corresponding one of said filters matched to one of said coded pulses F j , j=(N+n-c) mod N; and means for coherently summing the outputs of said filters generated during said detection intervals.
Claim 4
Independent Claim
256 words
An apparatus for ranging, said apparatus comprising: means for transmitting a sequence of coded pulses F 1 , F 2 , . . . , F 0 , F 1 , . . . , F N-1 , each of said coded pulses F n , n=0, 1, 2, . . . , N-1, being coded in accordance with the (n+1)th row of a Frank or P4 matrix of dimension N×N; said means for transmitting being effective to cause each of said coded pulses to be spaced from adjacent ones of said coded pulses by time intervals t 0 , t 1 , . . . , t N-1 , each F n being followed immediately by a corresponding t n , the last N of said time intervals being denominated detection intervals; means for selecting an integer c from the set whose members are: 0, 1, 2, . . . , N-1; means for detecting returns of said coded pulses during each of said detection intervals; means for processing said returns, said means for processing comprising a plurality of N filters, each filter of said plurality of N filters being matched to a corresponding one of said coded pulses, said means for processing further comprising: means for passing each of said returns detected in each said detection interval t n through a corresponding one of said filters matched to one of said coded pulses F j , j=(N+n-c) mod N; and means for coherently summing the outputs of said filters generated during said detection intervals.
References Cited (Backward Citations)
No citation records indexed.
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