System for the calculation of at least one vehicular traffic check parameter
First Claim
1. A system for the calculation of at least one parameter for checking vehicular traffic travelling on at least two traffic lanes, wherein said system comprises:
- a pulse modulated radar placed on a side that is not common to said at least two lanes and overlooking said at least two lanes from a predetermined height h, said radar emitting pulses of a given carrier frequency fo having a pulse width τ
, with a radiation diagram that is narrow in plan and sufficiently wide in elevation to cover said at least two lanes and enable simultaneously checking of said at least two lanes, and inclined at an elevation angle α
s and plan angle α
g, the values of τ
, α
s, and α
g being chosen such that there is at least one range bin of said radar included in a lane, and said radar also receiving echo signals;
a signal processing module comprising a sampler-encoder for said received echo signals, means for computing Fourier transform of an integer number N of temporal samples output from said sampler-encoder for each range bin corresponding to one lane, a smoothing filter which smoothes amplitude of frequency samples output from said Fourier transform computing means, and means for comparing amplitudes of samples output from said smoothing filter with a given threshold to detect passage of vehicles in each lane; and
a parameter extraction module which extracts said at least one parameter based on the output from said comparison means and samples output from said smoothing filter.
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Abstract
This invention comprises a system for calculating at least one vehicular traffic check parameter. The system according to the invention includes a pulse modulated radar placed at a high point at the side of the lanes to be monitored. The radar emits pulses having a frequency fo and width τ according to a radiation diagram. The radiation diagram is narrow in plan and sufficiently wide in elevation to cover all lanes to be monitored, and inclined in elevation and plan such that at least one range bin of the radar is included in a lane. Echo signals received by the radar are then processed by a signal processing module and a parameter extraction module. The invention is particularly useful in automobile traffic, for calculation of the number of vehicles travelling in lanes, the vehicles speed and length, etc. The advantage of the this inventive system compared with previous systems is that it enables simultaneous checking of several traffic lanes.
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Citations
9 Claims
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1. A system for the calculation of at least one parameter for checking vehicular traffic travelling on at least two traffic lanes, wherein said system comprises:
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a pulse modulated radar placed on a side that is not common to said at least two lanes and overlooking said at least two lanes from a predetermined height h, said radar emitting pulses of a given carrier frequency fo having a pulse width τ
, with a radiation diagram that is narrow in plan and sufficiently wide in elevation to cover said at least two lanes and enable simultaneously checking of said at least two lanes, and inclined at an elevation angle α
s and plan angle α
g, the values of τ
, α
s, and α
g being chosen such that there is at least one range bin of said radar included in a lane, and said radar also receiving echo signals;a signal processing module comprising a sampler-encoder for said received echo signals, means for computing Fourier transform of an integer number N of temporal samples output from said sampler-encoder for each range bin corresponding to one lane, a smoothing filter which smoothes amplitude of frequency samples output from said Fourier transform computing means, and means for comparing amplitudes of samples output from said smoothing filter with a given threshold to detect passage of vehicles in each lane; and a parameter extraction module which extracts said at least one parameter based on the output from said comparison means and samples output from said smoothing filter. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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Specification