System for determining position and velocity of targets from signals scattered by the targets
First Claim
1. A system for using signals scattered by targets to determine position and velocity for each of the targets in a position space, comprising a set of transmitters and receivers of electromagnetic or acoustic signals, said transmitters and receivers dispersed to known points in the position space, where each pair of transmitter and receiver, mono-static or bi-static, is named a measuring facility, further comprising analysis equipment for storage and analysis of received signals, which includes determination of instants for transmission and reception according to established principles for radar and parameterising of received signals as a function of path between point of transmission and point of reception, however without the usual requirement in radar on directional information, characterised inthat the range of the transmitters is chosen so that one target at an arbitrary point within the position space can be measured via scattering in the target by at least four measuring facilities, that for each measuring facility a target detection takes place with constant false alarm rate—
- CFAR—
where the noise intensity is given a threshold value and the cells where the signal intensity surpasses the threshold value are given to be target candidates, that the analysis equipment utilises a target positioning algorithm that implies that each measuring facility φ
places nφ
target candidates in nφ
of N resolution cells in a 2-dimensional linear space of range and Doppler velocities S2φ
associated to the measurement facility and that 3-dimensional positions and 3-dimensional Doppler velocities are represented as a 6-dimensional linear position and velocity space S6 partitioned into N3 resolution cells X ⊂
S6 with the same resolution of range and Doppler velocity as found in the measurement facilities and that the analysis equipment, based on the assumption that there is equal probability that a target is found in each and every of the cells X ⊂
Yjφ
, where Yjφ
⊂
S6 is a sub-set representing a single target candidate j=1,2, . . . , nφ
at some single measuring facility φ
, and also based on the expected number of targets calculates, for each cell X ⊂
Yjφ
∩
Yj′
φ
′
∩
. . . ∩
Yj(n)φ
(n) which represents detections at at least n≧
4 measuring facilities, the probability pFA(n,M,N) that the cell contains a false alarm emanating from intersections between sub-sets Yjφ
which originate from different targets and gives, when the probability falls below a predefined value, that the intersection contains at least one target and extracts through this target positions and target velocities.
1 Assignment
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Accused Products
Abstract
The present invention relates to a system for using signals scattered by targets to determine position and velocity for each of the targets and comprises a set of transmitters and receivers of electromagnetic or acoustic signals, said transmitters and receivers dispersed to known points. Each pair of transmitter and receiver, monostatic or bistatic, is named a measuring facility. The ranges of the transmitters are chosen so that a target at an arbitrary point within the position space can be measured via scattering in the target by at least four measuring facilities. For each measuring facility, target detection occurs with constant false alarm rate in the form of probabilities over resolution cells with regards to range and Doppler velocity and conceivable targets are placed in a 2-dimensional linear space belonging to the measuring facility. The 3-dimensional positions and 3-dimensional Doppler velocities are represented as a 6-dimensional linear position and velocity space subdivided into resolution cells with the same resolution of range and Doppler velocity that is found at the measuring facilities. For each intersection representing detections at at least four measuring facilities the probability is calculated that the intersection is a false alarm emanating intersections between subsets from different targets and when the probability falls below a predefined value, it is given that the intersection contains at least one target. The target positions and target velocities are extracted in this way.”
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Citations
10 Claims
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1. A system for using signals scattered by targets to determine position and velocity for each of the targets in a position space, comprising a set of transmitters and receivers of electromagnetic or acoustic signals, said transmitters and receivers dispersed to known points in the position space, where each pair of transmitter and receiver, mono-static or bi-static, is named a measuring facility, further comprising analysis equipment for storage and analysis of received signals, which includes determination of instants for transmission and reception according to established principles for radar and parameterising of received signals as a function of path between point of transmission and point of reception, however without the usual requirement in radar on directional information, characterised in
that the range of the transmitters is chosen so that one target at an arbitrary point within the position space can be measured via scattering in the target by at least four measuring facilities, that for each measuring facility a target detection takes place with constant false alarm rate— - CFAR—
where the noise intensity is given a threshold value and the cells where the signal intensity surpasses the threshold value are given to be target candidates,that the analysis equipment utilises a target positioning algorithm that implies that each measuring facility φ
places nφ
target candidates in nφ
of N resolution cells in a 2-dimensional linear space of range and Doppler velocities S2φ
associated to the measurement facility and that 3-dimensional positions and 3-dimensional Doppler velocities are represented as a 6-dimensional linear position and velocity space S6 partitioned into N3 resolution cells X ⊂
S6 with the same resolution of range and Doppler velocity as found in the measurement facilities andthat the analysis equipment, based on the assumption that there is equal probability that a target is found in each and every of the cells X ⊂
Yjφ
, where Yjφ
⊂
S6 is a sub-set representing a single target candidate j=1,2, . . . , nφ
at some single measuring facility φ
, and also based on the expected number of targetscalculates, for each cell X ⊂
Yjφ
∩
Yj′
φ
′
∩
. . . ∩
Yj(n)φ
(n) which represents detections at at least n≧
4 measuring facilities, the probability pFA(n,M,N) that the cell contains a false alarm emanating from intersections between sub-sets Yjφ
which originate from different targets andgives, when the probability falls below a predefined value, that the intersection contains at least one target and extracts through this target positions and target velocities. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
- CFAR—
Specification