Method and system for detecting radar signals

• US 20060258296A1
• Filed: 12/23/2005
• Published: 11/16/2006
• Est. Priority Date: 05/12/2005
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Steer, David, Smith, Adrian
• Granted Patent: US 8,179,825 B2
• Time in Patent Office: Days
• US Class Current: 455/67.130
• CPC Class Codes: G01S 7/021 Auxiliary means for detecting or identifying radar signals or the like, e.g. radar jamming signals
• CPC Class Codes: H04K 2203/36 including means for exchanging jamming data between transmitter and receiver, e.g. in forward or backward direction
• CPC Class Codes: H04K 3/224 with countermeasures at transmission and/or reception of the jammed signal, e.g. stopping operation of transmitter or receiver, nulling or enhancing transmitted power in direction of or at frequency of jammer
• CPC Class Codes: H04K 3/226 Selection of non-jammed channel for communication spectrum sharing arrangements H04W16/14; selection of wireless resources by user or terminal H04W72/02
• CPC Class Codes: H04K 3/822 by detecting the presence of a surveillance, interception or detection
• CPC Class Codes: H04W 16/14 Spectrum sharing arrangements between different networks

Abstract

A method and system for detecting RADAR signals in a radio communications system is provided. A detection system includes a pulse examination. Based on the result from the examination/analysis, a RADAR pulse is detected. The examination/analysis may include a correlator for correlating received pulses with themselves or samples previously obtained.

Claims

1. A system for detecting a RADAR signal in a communications network which utilizes signals different from the RADAR signal, comprising:

a receiver for receiving a first pulse;

a correlator for correlating the first pulse with a second pulse; and

a detector for detecting, based on the correlation measurement, whether the first pulse is a RADAR pulse.

2. A system according to claim 1, wherein the second pulse is the first pulse, and the correlator includes a self-correlator for correlating the first pulse with itself to obtain self-correlation.

3. A system according to claim 2, wherein the self-correlator correlates the samples of the first pulse with themselves at one or more non-zero time offsets.

4. A system according to claim 3, wherein the self-correlator is capable of calculating the average of the self-correlation, the normalization of the self-correlation, or a combination thereof, and

the detector comparing the self-correlation, the average of the self-correlation or the normalization of the self-correlation with a threshold.

5. A system according to claim 1, further comprising:

a memory system having one or more memories for storing previously received pulses, externally obtained pre-defined pulses or a combination thereof.

6. A system according to claim 5, wherein the correlator is provided for correlating the first pulse with the previously received pulses, the externally obtained pre-defined pulses or a combination thereof to obtain correlation.

7. A system according to claim 5, further comprising:

a circuit for examining one or more characteristics of the first pulse,

wherein the detector detects the RADAR pulse based on the output from the correlator, or the output from the correlator and the one or more characteristics.

8. A system according to claim 7, wherein the correlator includes at least one of:

a first correlator for correlating the first pulse with itself to obtain self-correlation, and

a second correlator for correlating the first pulse with the previously received pulses, the externally obtained pre-defined pulses or a combination thereof to obtain correlation.

9. A system according to claim 8, wherein the first correlator, the second correlator or a combination thereof is enabled based on the examination result.

10. A system according to claim 8, wherein the circuit includes:

a measurement module for measuring the one or more characteristics of the first pulse, and/or

a header detector for detecting a header or a standardized signature signal that identifies the format of a communications transmission.

11. A system according to claim 7, wherein the circuit includes:

a circuit for implementing pattern matching to the first pulse.

12. A system according to claim 11, further comprising:

a memory system having a memory for storing information for the pattern matching.

13. A system according to claim 1, further comprising:

a memory circuit for logging a newly received RADAR pulse for later use in searching for periodicities corresponding to a RADAR signal.

14. A system according to claim 5, wherein the memory system includes:

a selector for selectively storing the externally obtained pre-defined pulse or the previously received pulse into the memories.

15. A system according to claim 5, wherein the memory system includes:

an encryption module for encrypting the externally obtained pulse sequences and/or the received pulse before storing, and a decryption module for decrypting data stored in the memory for the correlation.

16. A system according to claim 5, wherein the one or more memories include:

a first section and a second section, where the externally obtained pre-defined pulse is directly stored in the first section, and the previously received pulse is stored in the second section after the encryption.

17. A system according to claim 5, wherein the memory system uses a key selector for randomly selecting one or more keys from the pulse received at the receiver.

18. A system according to claim 17, wherein the memory system includes a key storage for storing-the key.

19. A system according to claim 7, wherein the detector coordinates the actions of the correlator, the circuit and the memory system.

20. A system according to claim 5, wherein the correlator includes a self-correlator for correlating the first pulse with itself to obtain self-correlation, and the first pulse with a low self-correlation is stored in the memory.

21. A system according to claim 1, wherein a plurality of communications nodes forms the communications network, each having a transceiver for the communication of signals among the communications nodes, and at least one of the communications nodes having the correlator, the detector or a combination thereof.

22. A system according to claim 21, wherein the system further comprises:

a processor for determining an action of the communications node in response to the detection of the RADAR pulse.

23. A system according to claim 22, wherein the detection of the RADAR pulse is exchanged between the communications nodes for channel sharing.

24. A method of detecting a RADAR signal in a communications network which utilizes signals different from the RADAR signal, comprising the steps of:

receiving a first pulse;

correlating the first pulse with a second pulse; and

detecting, based on the correlation measurement, whether the first pulse is a RADAR pulse.

25. A method according to claim 24, further comprising the step of:

examining one or more characteristics of the first pulse,

the correlation step being implemented based on the examination result.

26. A method according to claim 24, further comprising the step of:

logging a newly received pulse for later use in searching for periodicities corresponding to a RADAR signal.

27. A method according to claim 25, wherein the second pulse is the first pulse, and the correlation step includes the step of:

self-correlating the first signal with itself.

28. A method according to claim 25, wherein the second pulse is associated with previously received pulses, externally obtained pre-defined pulses or a combination thereof, and the correlation step includes the step of:

correlating the first pulse with the previously received pulses or the pre-defined RADAR pulses in a memory.

29. A method according to claim 27, wherein the self-correlation step is implemented based on the examination result.

30. A method according to claim 28, wherein the correlation step is implemented based on the examination result.

31. A method according to claim 24, wherein the correlation step includes the steps of:

self-correlating the first signal with itself; and

correlating the first pulse with previously received pulses or pre-defined RADAR pulses stored in a memory.

32. A method according to claim 31, further comprising the step of:

storing the first pulse in the memory if the first pulse has a low self-correlation.

33. A method according to claim 31, wherein the detecting step detects the RADAR pulse based on at least one of the results of the self-correlation step and the correlation step.

34. A method according to claim 24, wherein a plurality of communications nodes forms the commutations network, and further comprising the step of:

at a communications node, initiating a new action of the commutations node in response to the detection of the RADAR pulse.

35. A method according to claim 24, wherein a plurality of communications nodes forms the commutations network, and further comprising the step of:

among the commutations nodes, exchanging the correlation result, the detection result, or a combination thereof.