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1. (WO2019000047) A SYSTEM AND METHOD OF DETECTING OBJECTS
ملاحظة: نص مبني على عمليات التَعرف الضوئي على الحروف. الرجاء إستخدام صيغ PDF لقيمتها القانونية

An object detection system comprising plurality of nodes, each node having a transmitter configured to transmit a radar signal as a beam, and one or more receivers configured to receive a reflected radar signal; the nodes and transmitters being arranged such that the radar beam of one transmitter at least partly overlaps with the radar beam from the transmitter at an adjacent one of the nodes; the system comprising a processor configured to receive a digitised signal from each node, process the digitised signal to detect characteristics of any Doppler effects created by the movement of an object through one or more of the radar beams, compare the Doppler characteristics with Doppler signatures associated with known objects, and thereby classify the object

The object detection system of claim 1 , wherein the transmitted radar signals

comprise continuous wave radar signals.

The object detection system of claim 1 or 2, wherein the transmitted radar signals are constant-frequency radar signals, and wherein the signals of any two overlapping beams have different frequencies.

The object detection system of any preceding claim, wherein one or more of the nodes comprises two receivers in a monopulse configuration, and wherein the processor is configured to extract bearing information from the digitised signal.

The object detection system of any preceding claim, wherein any two adjacent receivers at respective adjacent nodes are angled towards each other.

The object detection system of any preceding claim, wherein the processor is

configured to process the digital signal by applying fast Fourier transforms ( FFTs) .

The object detection system of claim 6, wherein the processor is configured to further process the digital signal by applying peak and/or track detection.

The object detection system of any preceding claim, wherein the processor is a central processor and each node further comprises a node processor configured to sample, filter, and digitise the signal from the respective receiver(s), and transmit the digitised signal(s) to the local processor.

9. The object detection system of claim 8, wherein the nodes are linked to the local processor over a communications link.

10. The object detection system of any preceding claim, wherein the transmitted radar signals each have a horizontal beam width of 70 to 90 degrees.

11. The object detection system of any preceding claim, wherein the transmitted radar signals each comprise radio signals having a frequency that is between about 10 GHz and about 100 GHz

12. The object detection system of any preceding claim, wherein the transmitted radar signals each comprise radio signals having a frequency that is between about 24 GHz and about 24.25 GHz.

13. The object detection system of any preceding claim, configured to detect objects having a radar cross section of more than about -40 dBm2.

14. The object detection system of any preceding claim, wherein the receiver(s) and transmitter at each node are housed in a unit and mounted on, at, or adjacent to a perimeter fence, such that the node extends above the perimeter fence.

15. The object detection system of any preceding claim, wherein the nodes are spaced

15 to 60m apart.

16. The object detection system of any preceding claim, wherein the nodes are spaced

20 to 30m apart.

17. A method for detecting moving objects comprising:

providing a plurality of nodes, each node having a transmitter transmitting a radar signal as a beam, and one or more receivers to sense a reflected radar signal, the transmitters being arranged such that the radar beam of one transmitter at least partly overlaps with the radar beam from the transmitter at an adjacent one of the nodes;

receiving and digitising signals from the radar receivers;

processing the digitised signals to detect characteristics of any Doppler effects created by the movement of an object through one or more of the radar beams; comparing the detected Doppler characteristics with Doppler signatures associated with known objects to classify the object; and

triggering an alert upon the classification of the object.

18. The method of claim 17, wherein the transmitters each transmit continuous wave radar signals.

19. The method of claim 17 or 18, wherein the transmitters each transmit constant- frequency radar signals, and wherein the signals of any two overlapping beams have different frequencies.

20. The method of any one of claims 17 to 19, wherein one or more of the nodes

comprises two receivers in a monopulse configuration, and the step of processing the signal comprises extracting bearing information.

21. The method of any one of claims 17 to 20, wherein data from each receiver is oversampled.

22. The method of any one of claims 17 to 21 , wherein the step of processing the signal comprises applying short-time fast Fourier transforms.

23. The method of any one of claims 17 to 23, wherein the step of processing the signal comprises creating Doppler spectrograms, and the spectrograms are compared to Doppler spectrograms associated with known objects.

24. The method of any one of claims 17 to 23, wherein the step of processing the signal comprises applying peak and/or track detection.

25. The method of any one of claims 17 to 24, wherein the processor is a central processor and further comprising the step of sampling, filtering, and digitising the signal from each receiver at a respective node processor, and transmitting the digitised signals to the local processor.

26. The method of any one of claims 17 to 25, wherein the transmitted radar signals each have a horizontal beam width of 70 to 90 degrees.

27. The method of any one of claims 17 to 26, wherein the transmitted radar signals each have a frequency that is between about 24 GHz and about 24.25 GHz.

28. The method of any one of claims 17 to 27, configured to detect objects having a radar cross section of more than about -40 dBm2.

29. The method of any one of claims 17 to 28, further comprising comparing the

detected Doppler characteristics with known Doppler signatures associated with known objects not of interest, and in the case that the characteristics do not correlate to one such known object, triggering the alert.

30. The method of any one of claims 17 to 29, further comprising comparing the detected Doppler characteristics with known Doppler signatures associated with known objects of interest; and, in the case that the characteristics correlate to one such known object, triggering the alert.

31. The method of any one of claims 17 to 30, comprising training the processor to recognise known objects using machine learning.