Method and system for detection of passive intermodulation interference emissions

• US 8,369,812 B2
• Filed: 02/05/2009
• Issued: 02/05/2013
• Est. Priority Date: 03/20/2008
• Status: Active Grant

• Current Assignee: Honeywell International Inc.
• Original Assignee: Honeywell International Inc.
• Inventors: Lehman, Bob
• Primary Examiner(s): Donovan, Lincoln
• Assistant Examiner(s): CHENG, DIANA
• Application Number:
  US12/366,412
• Publication Number:
  US 20090239475A1
• Time in Patent Office: 1,461 Days
• Field of Search: 455230-295
• US Class Current: 455/295
• CPC Class Codes: H04B 1/109 by improving strong signal performance of the receiver when strong unwanted signals are present at the receiver input
• CPC Class Codes: H04B 17/345 Interference values signal-to-interference ratio [SIR] or carrier-to-interference ratio [CIR] H04B17/336

Abstract

A method and system for detecting intermodulation emissions, such as passive intermodulation emissions, is provided. The method comprises retrieving signal quality measurement (SQM) data, and determining whether there is an intermodulation hit in the SQM data. If there is no intermodulation hit, the SQM data is stored in a first data set; if there is an intermodulation hit, the SQM data is stored in a second data set. The method then determines whether there are one or more faults in the first data set. If there are, a confirmation count for an intermodulation failure is cleared, and the method starts again. If there are not one or more faults in the first data set, a determination is made whether there are one or more faults in the second data set. If not, the confirmation count is cleared, and the method starts again. An intermodulation failure can be confirmed if there are one or more faults in the second data set.

Claims

1. A method for detecting intermodulation emissions, the method comprising:

(a) retrieving signal quality measurement (SQM) data generated by a receiver without any test signal transmissions;

(b) determining whether there is an intermodulation hit in associated with the SQM data, the intermodulation hit defined as a condition that exists when one or more potential intermodulation product frequency or frequencies from a current set of normal operation transmit frequencies coincide with one or more monitored normal operation receive frequency or frequencies;

(i) storing the SQM data in a first data set if there is no intermodulation hit; and

(ii) storing the SQM data in a second data set if there is an intermodulation hit;

(c) determining whether there are one or more faults in the first data set;

(i) clearing a confirmation count for an intermodulation failure if there are one or more faults in the first data set; and

(ii) returning to step (a) to restart the method;

(d) determining whether there are one or more faults in the second data set if there are not one or more faults in the first data set; and

(i) clearing the confirmation count if there are not one or more faults in the second data set; and

(ii) returning to step (a) to restart the method.

2. The method of claim 1, further comprising confirming an intermodulation failure if there are one or more faults in the second data set.

3. The method of claim 2, wherein confirming the intermodulation failure further comprises:

determining whether the confirmation count for the intermodulation failure is equal to a maximum selectable amount;

if the confirmation count is not equal to the maximum selectable amount;

incrementing the confirmation count to a next value; and

returning to step (a) to restart the method;

if the confirmation count is equal to the maximum selectable amount, determining whether a failure flag for the intermodulation failure is set;

if the failure flag is set, returning to step (a) to restart the method;

or

if the failure flag is not set;

setting the failure flag;

reporting the intermodulation failure; and

returning to step (a) to restart the method.

4. The method of claim 3, further comprising:

clearing the first data set, the second data set, the failure flag, and the confirmation count prior to restarting a timer.

5. A computer program product, comprising:

a computer-readable medium having program instructions stored thereon for a method for detecting intermodulation emissions according to claim 1.

6. A computer program product, comprising:

a computer-readable medium having program instructions stored thereon for a method of detecting passive intermodulation emissions, the method comprising;

(a) retrieving signal quality measurement (SQM) data generated by a receiver without any test signal transmissions;

(b) determining whether there is a passive intermodulation hit associated with the SQM data, the passive intermodulation hit defined as a condition that exists when one or more potential intermodulation product frequency or frequencies from a current set of normal operation transmit frequencies coincide with one or more monitored normal operation receive frequency or frequencies;

(i) storing the SQM data in a first data set if there is no passive intermodulation hit; and

(ii) storing the SQM data in a second data set if there is a passive intermodulation hit;

(c) returning to step (a), if a timer has not expired, to restart the method;

(d) determining whether there are one or more faults in the first data set if the timer has expired;

(i) clearing a confirmation count for a passive intermodulation failure if there are one or more faults in the first data set; and

(ii) returning to step (a) to restart the method;

(e) determining whether there are one or more faults in the second data set if there are not one or more faults in the first data set; and

(i) clearing the confirmation count if there are not one or more faults in the second data set; and

(ii) returning to step (a) to restart the method;

(f) confirming a passive intermodulation failure if there are one or more faults in the second data set.

7. The computer program product of claim 6, wherein confirming the passive intermodulation failure further comprises:

determining whether a confirmation count for the passive intermodulation failure is equal to a selectable threshold value;

if the confirmation count is not equal to the selectable threshold value;

incrementing the confirmation count to a next value; and

returning to step (a) to restart the method;

if the confirmation count is equal to the selectable threshold value, determining whether a failure flag for the passive intermodulation failure is set;

if the failure flag is set, returning to step (a) to restart the method;

or

if the failure flag is not set;

setting the failure flag;

reporting the passive intermodulation failure; and

returning to step (a) to restart the method.

8. The computer program product of claim 7, further comprising:

clearing the first data set, the second data set, the timer, the failure flag, and the confirmation count prior to restarting the timer.

9. The computer program product of claim 6, wherein the program instructions stored on the computer-readable medium are implemented as part of an avionics protocol module.

10. The computer program product of claim 6, wherein the program instructions stored on the computer-readable medium are implemented as part of a satellite navigation protocol module.

11. A system for detecting passive intermodulation emissions, the system comprising:

at least one data receiver that outputs signal quality measurement (SQM) data without any test signal transmissions;

at least one data storage device that saves the SQM data from the data receiver;

at least one data processor operatively coupled to the data storage device; and

a program module having instructions executable by the processor to;

(a) retrieve the SQM data from the storage device;

(b) determine whether there is a passive intermodulation hit associated with the SQM data, the passive intermodulation hit defined as a condition that exists when one or more potential intermodulation product frequency or frequencies from a current set of normal operation transmit frequencies coincide with one or more monitored normal operation receive frequency or frequencies;

(i) store the SQM data in a first data set if there is no passive intermodulation hit; and

(ii) store the SQM data in a second data set if there is a passive intermodulation hit;

(c) determine whether there are one or more faults in the first data set;

(i) clear a confirmation count for a passive intermodulation failure if there are one or more faults in the first data set; and

(ii) repeat instructions (a) to (c);

(d) determine whether there are one or more faults in the second data set if there are not one or more faults in the first data set;

(i) clear the confirmation count if there are not one or more faults in the second data set; and

(ii) repeat instructions (a) to (d);

(e) confirm a passive intermodulation failure if there are one or more faults in the second data set.

12. The system of claim 11, further comprising one or more antennas, wherein at least one antenna is in signal communication with the data receiver.

13. The system of claim 12, further comprising at least one multi-channel transmitter, wherein at least one antenna is in signal communication with the multi-channel transmitter.

14. The system of claim 13, further comprising a transmit/receive coupler when the same antenna is in signal communication with the data receiver and the multi-channel transmitter, the coupler configured to provide signal communication between the antenna and the transmitter or the receiver.

15. The system of claim 14, wherein the transmit/receive coupler comprises a diplexer or a circulator, the coupler configured to couple, combine, or split transmit and receive communication signals to and from the antenna.

16. The system of claim 11, wherein the SQM data is sent to the first data set or the second data set from the data receiver via a virtual switch controlled by the processor.

17. The system of claim 11, wherein the instructions to confirm the passive intermodulation failure further comprises instructions to:

determine whether the confirmation count for the passive intermodulation failure is equal to a maximum selectable amount;

if the confirmation count is not equal to the selectable threshold value;

increment the confirmation count to a next value; and

repeat the instructions starting at step (a);

or

if the confirmation count is equal to the selectable threshold value, determine whether a failure flag for the passive intermodulation failure is set;

if the failure flag is set, repeat the instructions starting at step (a);

or

if the failure flag is not set;

set the failure flag;

report the passive intermodulation failure; and

repeat the instructions starting at step (a).

18. The system of claim 17, wherein the program module comprises further instructions to:

clear the first data set, the second data set, the failure flag, and the confirmation count prior to restarting a timer.

19. The system of claim 11, wherein the program module is implemented as part of an avionics protocol module on an aircraft.

20. The system of claim 11, wherein the program module is implemented as part of a satellite navigation protocol module on a satellite.