Radar system and method

• US 10,585,171 B2
• Filed: 06/20/2016
• Issued: 03/10/2020
• Est. Priority Date: 05/29/2007
• Status: Active Grant

• Current Assignee: Thales SA
• Original Assignee: Aveillant Limited (Thales SA)
• Inventors: Oswald, Gordon Kenneth Andrew, Webster, Craig Duncan, Smithson, Allan Geoffrey
• Primary Examiner(s): Windrich, Marcus E
• Application Number:
  US15/187,731
• Publication Number:
  US 20170082732A1
• Time in Patent Office: 1,359 Days
• CPC Class Codes: G01S 13/42 Simultaneous measurement of distance and other co-ordinates indirect measurement G01S13/46
• CPC Class Codes: G01S 13/87 Combinations of radar systems, e.g. primary radar and secondary radar
• CPC Class Codes: G01S 13/951 ground based
• CPC Class Codes: G01S 2013/0263 Passive array antenna
• CPC Class Codes: G01S 7/414 Discriminating targets with respect to background clutter
• CPC Class Codes: Y02A 90/10 Information and communication technologies [ICT] supporting adaptation to climate change, e.g. for weather forecasting or climate simulation
• CPC Class Codes: Y02B 10/30 Wind power

Abstract

A radar system for discriminating between sources of radar interference and targets of interest. The system includes a transmitter for transmitting radar signals into a region, a receiver for receiving return signals of the radar signals returned from within the region, and a processor for processing the return signals to discriminate between return signals returned from a first object and return signals returned from a second object where the return signals from the second object comprise both zero and non-zero Doppler components and interfere with the return signals from the first object. The radar system is operable for discriminating between the return signals when the return signals are received at a distance from the second object which is less than a proximity limit based on the geometry of the object.

Claims

1. A radar system for discriminating between sources of radar interference and targets of interest, the system comprising:

a static transmitter configured to transmit radar signals persistently into a volume of space without movement of a region of illumination by electronic or mechanical scanning;

a multi-beam receiver configured to receive return signals of said radar signals returned from within said volume of space; and

a processor configured to process the return signals to discriminate between return signals returned from a first object and return signals returned from a second object based on respective data representing an evolution of the spectral spread of said Doppler components for each object over time, wherein said return signals from said objects comprise Doppler components exhibiting a spectral spread of Doppler components;

wherein the processor is configured to maintain historical persistently-acquired data from the whole of said volume of space, including persistently-acquired phase and

persistently-acquired amplitude data associated with said return signals over time, and to process the return signals to discriminate between return signals returned from a first object and return signals returned from a second object based on said stored historical, persistently-acquired phase and amplitude data; and

wherein the processor is further configured to determine conformity of an evolution of the spectral spread of said Doppler components with a model derived from the historical data in terms of historic signal characteristics stored by the processor.

2. A radar system as provided in claim 1, wherein at least one of said first and second objects comprises an unmanned aircraft and wherein the processor is configured to discriminate between said unmanned aircraft and the other of said first and second objects based on said discrimination.

3. A radar system as provided in claim 2, wherein the processor is configured to discriminate between said unmanned aircraft even when said unmanned aircraft exhibits a radar cross-section that is an order of magnitude smaller compared to a radar cross-section of the other of said first and second objects.

4. A radar system as provided in claim 2, wherein the processor is configured to discriminate between said unmanned aircraft and a conventional aircraft.

5. A radar system as provided in claim 2, wherein the processor is configured to discriminate between said unmanned aircraft and said other of said first and second objects in conjunction with a primary air surveillance radar whereby to enhance air surveillance capabilities.

6. A radar system as provided in claim 1, wherein the processor is configured to measure a respective time, range, range rate and angular position for each object based on said return signals and associated Doppler characteristics.

7. A radar system as claimed in claim 1, wherein said processor is configured to determine conformity of an evolution of phase and/or amplitude data associated with the Doppler components with a model based on phase and/or amplitude histories over time;

and to discriminate between and/or to classify objects or tracks of objects based on said conformity.

8. A radar system as claimed in claim 7, wherein said processor is configured to determine conformity of at least one of range, range rate and angular position measurements with a model based on a prior evolution of at least one of range, range rate and angular position with time;

and to discriminate between and/or to classify objects or tracks of objects based on said conformity.

9. A radar system as claimed in claim 1, wherein said processor is configured to classify said objects based on said stored historical data.

10. A radar system as claimed in claim 1, wherein said processor is configured to identify at least one track of at least one of said first and second objects over time based on said stored historical data and to discriminate between return signals returned from the first object and return signals returned from the second object based on maid at least one track so identified.

11. A radar system as claimed in claim 1, wherein said processor is configured to process said return signals at a resolution, of at least 100 Doppler bins to be sufficient, when at least one of said first object and said second object comprises a rotating element, to characterize the manner in which the spectral spread of Doppler components exhibited by return signals from said rotating element changes progressively, and cyclically, within each period of rotation thereby discriminating between said first and second objects.

12. A method, performed in a radar system, of discriminating between sources of radar interference and targets of interest, the method comprising:

persistently transmitting radar signals into a volume of space without movement of a region of illumination by electronic or mechanical scanning;

receiving return signals of said radar signals returned from within said volume of space; and

processing the return signals to discriminate between return signals returned from a first object and return signals returned from a second object based on respective data representing an evolution of the spectral spread of said Doppler components for each object over time, wherein said return signals from said objects comprise Doppler components exhibiting a spectral spread of Doppler components;

wherein processing comprises maintaining persistently-acquired historical data from the whole of said volume of space, including persistent phase and amplitude data associated with said return signals over time, and processing the return signals to discriminate between return signals returned from a first object and return signals returned from a second object based on said stored, historical, persistently-acquired phase and amplitude data, and wherein said processing further comprises determining a conformity of an evolution of the spectral spread of said Doppler components with a model derived from the historical data in terms of historic signal characterisitics stored by the processor.