EP0334560A2
Expired / Lapsed
EP
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Radar video detector and target tracker
Assignee: Litton Marine Systems Inc
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Filing: 1989-03-17
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Granted: —
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Expires: 2009-03-17
Abstract
Abstract A system for detecting and tracking a multiplicity of targets averages (30) radar video returns over small sectors for data smoothing and noise reduction (40), provides adaptive thresholding by determining noise levels in an area of interest and establishes a detection threshold in accordance with such noise level, stores (Memory 1, Memory 2) the video data for each target of interest so that multiple targets on the same bearing may be tracked, and reduces the probability of target swapping by adjusting the target window (49) in accordance with target size and weighting the cells within the window.
Inventors
- 👤 Johnny A. Cornett
- 👤 James D. Corbett
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-24 16:44
CPC Classifications
G; G01; G01S; G01S13/00; G01S13/02; G01S7/00; G01S7/02; G01S7/28; G01S7/285; G01S7/292; G01S7/2923; G01S7/2927; G01S13/66; G01S13/72
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
196 words
Apparatus for detecting radar return video signals characterising in that it comprises: means (28) for receiving the video signals within predetermined range bins and angle sectors for providing signals representative of average amplitudes of a plurality of successive radar returns within cells of a matrix of cells formed by the range bins and the angle sectors, each range bin forming a row in the matrix and each angle sector forming a column; means for storing the signals in memory units (Memory 1, Memory 2) corresponding to the cells; Means (40) responsive to the signals for computing a mean value and a mean deviation value for said signals in at least one row of the matrix; means coupled to the computing means and the memory means for subtracting a linear combination of the mean value and the mean deviation value from the signals in each of the memory units, thereby establishing noise reduced signals; and means responsive to the noise reduced signals for setting positive noise reduced signals to zero in cells not having at least one abutting cell with a positive noise reduced signal, abutting cells with positive noise reduced signals therein representing detected target units.
Claim 2
Dependent Claim
196 words
Apparatus for detecting radar return video signals characterising in that it comprises: means (28) for receiving the video signals within predetermined range bins and angle sectors for providing signals representative of average amplitudes of a plurality of successive radar returns within cells of a matrix of cells formed by the range bins and the angle sectors, each range bin forming a row in the matrix and each angle sector forming a column; means for storing the signals in memory units (Memory 1, Memory 2) corresponding to the cells; Means (40) responsive to the signals for computing a mean value and a mean deviation value for said signals in at least one row of the matrix; means coupled to the computing means and the memory means for subtracting a linear combination of the mean value and the mean deviation value from the signals in each of the memory units, thereby establishing noise reduced signals; and means responsive to the noise reduced signals for setting positive noise reduced signals to zero in cells not having at least one abutting cell with a positive noise reduced signal, abutting cells with positive noise reduced signals therein representing detected target units.
Claim 3
Dependent Claim
57 words
Apparatus according to claim 1 characterised in that it further includes means (46) for establishing at least one detection window, each window commencing in range and angle at selected positions, extending in range for a plurality (m) range bins and extending angularly for a multiplicity (n) angle sectors, thereby establishing windows with m x n cells therein.
Claim 4
Dependent Claim
179 words
Apparatus according to claim 2 characterised in that it further includes; means (47) for counting the detected target units in each window to provide a signal representative of a target size therein; means (51) for weighting the detected target units in accordance with row positions to obtain a row weighted signal for each row; means for weighting the detected target units in accordance with column positions to obtain a column weighted signal for each column; means for summing the row weighted signals, the column weighted signals, and signals in all cells to obtain a signal representative of a row weighted sum, a signal representative of a column weighted sum, and a signal representative of a total signal sum, respectively, for each window; and means (57, 59) responsive to the signals representative of the row and column weighted sums and the signal representative of the total signal sum for dividing the signals representative of the row and column weighted sums by the signal representative of said total signal sum to obtain a signal representative of target position in each window.
Claim 5
Dependent Claim
47 words
Apparatus according to claim 3, characterised in that it further includes means (49) responsive to the signal representative of the target size, and the signals representative of the row and target position for adjusting window size in accordance with the target size and window centering the target.
Claim 6
Dependent Claim
82 words
Apparatus according to claim 4, characterised in that the return video signals are detected by a radar system having a scanning antenna and means for determining angular locations of the targets in the windows relative to a predetermined angular reference further includes: means (52) for determining speeds and headings of moving targets in the windows and providing signals representative thereof; and means (65) responsive to the speed and heading representative signals for providing predicted positions of the targets for subsequent antenna scans.
Claim 7
Independent Claim
150 words
A method of detecting radar return video signals, characterised in that it includes the steps of: receiving the video signals within predetermined range bins and angle sectors, the range bins and angle sectors forming cells in a range-angle matrix of cells; averaging signal amplitudes of successive radar returns for each cell, to provide signals representative of average amplitudes in each cell; storing the signals in memory units corresponding to the cells; computing a mean value and a mean deviation value of said signals in at least one row of the matrix; subtracting a linear combination of the mean value and mean deviation value from the signals stored in the memory units, thereby establishing noise reduced signals; and setting positive noise reduced signals to zero in cells not having at least one abutting cell with a positive noise signal, abutting cells with positive noise reduced signals therein representing detected target units.
Claim 8
Independent Claim
150 words
A method of detecting radar return video signals, characterised in that it includes the steps of: receiving the video signals within predetermined range bins and angle sectors, the range bins and angle sectors forming cells in a range-angle matrix of cells; averaging signal amplitudes of successive radar returns for each cell, to provide signals representative of average amplitudes in each cell; storing the signals in memory units corresponding to the cells; computing a mean value and a mean deviation value of said signals in at least one row of the matrix; subtracting a linear combination of the mean value and mean deviation value from the signals stored in the memory units, thereby establishing noise reduced signals; and setting positive noise reduced signals to zero in cells not having at least one abutting cell with a positive noise signal, abutting cells with positive noise reduced signals therein representing detected target units.
Claim 9
Dependent Claim
59 words
A method according to claim 6, characterised in that it further includes the step of establishing at least one detection window, each window commencing in range and angle at selected positions, extending in range for a plurality (m) range bins and extending angularly (n) for a multiplicity (n) angle sectors, thereby establishing m x n cells in a window.
Claim 10
Dependent Claim
157 words
A method according to claim 7, characterised in that it further includes the steps of; counting the target units in each window to provide a signal for each window representative of a target size therein; weighting the detected target units in accordance with row positions in the window to obtain a row weighted signal for each row; Weighting the detected target units in accordance with column positions in the windows to obtain a column weighted signal for each column; summing the row weighted signals, the column weighted signals, and signals in all cells in each window to obtain a signal representative of a row weighted sum, a signal representative of a column weighted sum, and a signal representative of a total signal sum, respectively, for each window; and dividing the row and column weighted sums of a window by the signal representative of the total sum to obtain a signal representative of target position in each window.
Claim 11
Dependent Claim
32 words
A method according to claim 8, characterised in that it further includes the steps of; adjusting each window size in accordance with a target size therein; and centering target in each window.
Claim 12
Dependent Claim
35 words
A method of claim 9, characterised in that it further includes the steps of: determining speeds and headings of moving targets in the windows; and calculating predicted positions of the targets at a subsequent time.
References Cited (Backward Citations)
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