Set mode passive location in TOA/TDOA modes
First Claim
1. A method of passively locating a target in TOA or TDOA mode comprising the steps of:
- subdividing into blocks a space in which a location area is situated; and
iteratively performing on the blocks, until a predetermined criterion is obtained, the steps of;
searching within each block for a presence of at least one point belonging to the location area;
excluding from the blocks any blocks that do not contain a point that belongs to the location area;
resubdividing into subblocks any blocks that contain a point that belongs to the location area;
replacing the blocks by the subblocks,wherein each iteration increases an accuracy of defining the location area, and the method further comprises the steps of;
forming a current selection from a first block that corresponds to an a priori search space;
forming a current list from the first block;
iteratively performing the steps of;
subdividing each block of a current list into a first, second, third, and fourth adjoining subblocks;
searching the first, second, third, and fourth subblocks for at least one point forming part of the location area, to produce searched subblocks;
selecting the searched subblocks having at least one point forming part of the location area, to produce selected subblocks;
updating the current list to obtain an updated list, by performing the steps of;
deleting blocks that have no selected subblocks; and
replacing blocks not deleted by the first, second, third, and fourth subblocks to form an updated current list,wherein;
the iteratively performed steps comprise a test to compare a resolution of the blocks that constitute the updated current list; and
the iteratively performed steps stop when the resolution is greater than a desired resolution.
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Abstract
The present invention addresses the resolving of the problems associated with the passive location of targets in TOA (Time of Arrival) or TDOA (Time Difference of Arrivals) mode. The method of passively locating a target in TOA or TDOA mode implements a meshing (subdivision) into blocks of the space in which the location area is situated. The set of the blocks that form this mesh is analyzed iteratively. On each iteration, each block of interest is subdivided into smaller identical subblocks. A block of interest is, according to the invention, a block including at least one point belonging to the location area being sought for which the shape is to be determined. The iterative process is stopped when the size of the subblocks obtained on the current iteration corresponds to the desired resolution. The invention applies in particular to the 2D or 3D location systems that include TOA and TDOA modes or mixed modes.
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Citations
9 Claims
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1. A method of passively locating a target in TOA or TDOA mode comprising the steps of:
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subdividing into blocks a space in which a location area is situated; and iteratively performing on the blocks, until a predetermined criterion is obtained, the steps of; searching within each block for a presence of at least one point belonging to the location area; excluding from the blocks any blocks that do not contain a point that belongs to the location area; resubdividing into subblocks any blocks that contain a point that belongs to the location area; replacing the blocks by the subblocks, wherein each iteration increases an accuracy of defining the location area, and the method further comprises the steps of; forming a current selection from a first block that corresponds to an a priori search space; forming a current list from the first block; iteratively performing the steps of; subdividing each block of a current list into a first, second, third, and fourth adjoining subblocks; searching the first, second, third, and fourth subblocks for at least one point forming part of the location area, to produce searched subblocks; selecting the searched subblocks having at least one point forming part of the location area, to produce selected subblocks; updating the current list to obtain an updated list, by performing the steps of; deleting blocks that have no selected subblocks; and replacing blocks not deleted by the first, second, third, and fourth subblocks to form an updated current list, wherein; the iteratively performed steps comprise a test to compare a resolution of the blocks that constitute the updated current list; and the iteratively performed steps stop when the resolution is greater than a desired resolution. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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Specification