METHODS AND APPARATUS FOR IMPROVED SENSOR VIBRATION CANCELLATION

• US 20170108374A1
• Filed: 10/16/2015
• Published: 04/20/2017
• Est. Priority Date: 10/16/2015
• Status: Active Grant

• Current Assignee: Raytheon BBN Technlogies Corp. (Rtx Corporation)
• Original Assignee: Raytheon BBN Technlogies Corp. (Rtx Corporation)
• Inventors: Coleman, Ronald Bruce, Mullen, Richard James, Mazurek, Jeffrey
• Granted Patent: US 10,921,180 B2
• Time in Patent Office: Days
• CPC Class Codes: G01J 1/0295 Constructional arrangements for removing other types of optical noise or for performing calibration
• CPC Class Codes: G01J 1/42 using electric radiation detectors optical or mechanical part G01J1/04; by comparison with a reference light or electric value G01J1/10
• CPC Class Codes: G01S 5/16 using electromagnetic waves other than radio waves

Abstract

Infrared sensing systems having improved vibration cancelation, and methods of achieving improved vibration cancelation. In one example, an infrared sensing system includes an infrared sensor configured to produce a sensor output signal representative of a response of the infrared sensor to infrared excitation and vibration excitation, an accelerometer configured to provide an acceleration signal responsive to the vibration excitation, and a controller, including an adaptive digital filter, coupled to the infrared sensor and to the accelerometer, and configured to receive the acceleration signal and to adjust coefficients of the adaptive digital filter so as to minimize coherence between a residual signal and the acceleration signal, the residual signal being a difference between the sensor output signal and a filter output signal from the adaptive digital filter.

Claims

1. An infrared (IR) sensing system comprising:

an IR sensor configured to produce a sensor output signal representative of a response of the IR sensor to an IR signature of interest and vibration excitation;

a reference sensor configured to provide a reference signal responsive to the vibration excitation; and

a controller, including an adaptive digital filter, coupled to the IR sensor and to the reference sensor, and configured to receive the reference signal and to adjust coefficients of the adaptive digital filter so as to minimize coherence between a residual signal and the reference signal, the residual signal being a difference between the sensor output signal and a filter output signal from the adaptive digital filter.

2. The IR sensing system of claim 1 wherein the reference sensor is an accelerometer and the reference signal is an acceleration signal.

3. The IR sensing system of claim 2 wherein the IR sensor and the accelerometer are disposed proximate one another on a movable platform.

4. The IR sensing system of claim 3 wherein the accelerometer is coupled to a housing of the IR sensor.

5. The IR sensing system of claim 2 wherein the controller is configured to implement a least-mean-square algorithm to minimize a portion of the sensor output signal that is correlated with the acceleration signal, thereby minimizing the coherence.

6. The IR sensing system of claim 5 wherein the controller is further configured to receive the residual signal.

7. The IR sensing system of claim 1 wherein the controller is configured to receive the residual signal and to implement a least-mean-square algorithm to minimize a portion of the sensor output signal that is correlated with the reference signal, thereby minimizing the coherence.

8. An infrared (IR) sensing system comprising:

an IR sensor configured to produce a sensor output signal representative of a response of the IR sensor to an IR event and vibration excitation;

at least one accelerometer configured to provide an acceleration signal responsive to the vibration excitation; and

a controller, including an adaptive digital filter, coupled to the IR sensor and to the at least one accelerometer, and configured to receive the acceleration signal and to adjust coefficients of the adaptive digital filter so as to minimize coherence between a residual signal and the acceleration signal, the residual signal being a difference between the sensor output signal and a filter output signal from the adaptive digital filter.

9. The IR sensing system of claim 8 wherein the controller is configured to implement a least-mean-square algorithm to minimize a portion of the sensor output signal that is correlated with the acceleration signal, thereby minimizing the coherence.

10. The IR sensing system of claim 8 wherein the controller is further configured to receive the residual signal.

11. The IR sensing system of claim 8 wherein the at least one accelerometer is coupled to a housing of the IR sensor.

12. A method of providing vibration cancelation in an infrared (IR) sensing system, the method comprising:

receiving a sensor output signal from an IR sensor, the sensor output signal being representative of a response of the IR sensor to an IR signature of interest and vibration excitation;

receiving at an input to an adaptive digital filter a reference signal from a reference sensor, the reference signal being responsive to the vibration excitation;

producing a residual signal by taking a difference between the sensor output signal and a filter output signal from the adaptive digital filter; and

adjusting coefficients of the adaptive digital filter so as to minimize coherence between the residual signal and the reference signal.

13. The method of claim 12 wherein the reference sensor is an accelerometer and the reference signal is an acceleration signal.

14. The method of claim 13 wherein adjusting the coefficients includes applying a least-mean-square algorithm to minimize a portion of the sensor output signal that is correlated with the acceleration signal, thereby minimizing the coherence between the residual signal and the acceleration signal.